Glossary — Part 3

2/20/25 AIM

portion of the flight to which the crossing altitude restriction applies, and the pilot is expected to comply with

the crossing altitude as a provision of the clearance. Any other clearance in which pilot execution is optional will

so state “AT PILOT’S DISCRETION.”

EXAMPLE−

1. “United Four Seventeen, descend and maintain six thousand.”

NOTE−

1. The pilot is expected to commence descent upon receipt of the clearance and to descend at the suggested rates until

reaching the assigned altitude of 6,000 feet.

EXAMPLE−

2. “United Four Seventeen, descend at pilot’ s discretion, maintain six thousand.”

NOTE−

2. The pilot is authorized to conduct descent within the context of the term at pilot’ s discretion as described above.

EXAMPLE−

3. “United Four Seventeen, cross Lakeview V −O−R at or above Flight Level two zero zero, descend and maintain

six thousand.”

NOTE−

3. The pilot is authorized to conduct descent at pilot’ s discretion until reaching Lakeview VOR and must comply with the

clearance provision to cross the Lakeview VOR at or above FL 200. After passing Lakeview VOR, the pilot is expected to

descend at the suggested rates until reaching the assigned altitude of 6,000 feet.

EXAMPLE−

4. “United Four Seventeen, cross Lakeview V−O−R at six thousand, maintain six thousand.”

NOTE−

4. The pilot is authorized to conduct descent at pilot’ s discretion, however, must comply with the clearance provision to cross

the Lakeview VOR at 6,000 feet.

EXAMPLE−

5. “United Four Seventeen, descend now to Flight Level two seven zero, cross Lakeview V −O−R at or below one zero

thousand, descend and maintain six thousand.”

NOTE−

5. The pilot is expected to promptly execute and complete descent to FL 270 upon receipt of the clearance. After reaching

FL 270 the pilot is authorized to descend “at pilot’ s discretion” until reaching Lakeview VOR. The pilot must comply with

the clearance provision to cross Lakeview VOR at or below 10,000 feet. After Lakeview VOR the pilot is expected to descend

at the suggested rates until reaching 6,000 feet.

EXAMPLE−

6. “United Three Ten, descend now and maintain Flight Level two four zero, pilot’ s discretion after reaching Flight Level

two eight zero.”

NOTE−

6. The pilot is expected to commence descent upon receipt of the clearance and to descend at the suggested rates until

reaching FL 280. At that point, the pilot is authorized to continue descent to FL 240 within the context of the term “at pilot’ s

discretion” as described above.

f. In case emergency authority is used to deviate from provisions of an ATC clearance, the pilot−in−command

must notify ATC as soon as possible and obtain an amended clearance. In an emergency situation which does

not result in a deviation from the rules prescribed in 14 CFR part 91 but which requires ATC to give priority to

an aircraft, the pilot of such aircraft must, when requested by ATC, make a report within 48 hours of such

emergency situation to the manager of that ATC facility.

g. The guiding principle is that the last ATC clearance has precedence over the previous ATC clearance. When

the route or altitude in a previously issued clearance is amended, the controller will restate applicable altitude

restrictions. If altitude to maintain is changed or restated, whether prior to departure or while airborne, and

previously issued altitude restrictions are omitted, those altitude restrictions are canceled, including departure

procedures and STAR altitude restrictions.

EXAMPLE−

1. A departure flight receives a clearance to destination airport to maintain FL 290. The clearance incorporates a DP which

ATC Clearances and Aircraft Separation 4−4−7

AIM 2/20/25

has certain altitude crossing restrictions. Shortly after takeoff, the flight receives a new clearance changing the maintaining

FL from 290 to 250. If the altitude restrictions are still applicable, the controller restates them.

2. A departing aircraft is cleared to cross Fluky Intersection at or above 3,000 feet, Gordonville VOR at or above 12,000

feet, maintain FL 200. Shortly after departure, the altitude to be maintained is changed to FL 240. If the altitude restrictions

are still applicable, the controller issues an amended clearance as follows: “cross Fluky Intersection at or above three

thousand, cross Gordonville V−O−R at or above one two thousand, maintain Flight Level two four zero.”

3. An arriving aircraft is cleared to the destination airport via V45 Delta VOR direct; the aircraft is cleared to cross Delta

VOR at 10,000 feet, and then to maintain 6,000 feet. Prior to Delta VOR, the controller issues an amended clearance as

follows: “turn right heading one eight zero for vector to runway three six I−L−S approach, maintain six thousand.”

NOTE−

Because the altitude restriction “cross Delta V−O−R at 10,000 feet” was omitted from the amended clearance, it is no longer

in effect.

h. Pilots of turbojet aircraft equipped with afterburner engines should advise ATC prior to takeoff if they

intend to use afterburning during their climb to the en route altitude. Often, the controller may be able to plan

traffic to accommodate a high performance climb and allow the aircraft to climb to the planned altitude without

restriction.

i. If an “expedite” climb or descent clearance is issued by ATC, and the altitude to maintain is subsequently

changed or restated without an expedite instruction, the expedite instruction is canceled. Expedite climb/descent

normally indicates to the pilot that the approximate best rate of climb/descent should be used without requiring

an exceptional change in aircraft handling characteristics. Normally controllers will inform pilots of the reason

for an instruction to expedite.

4−4−11. IFR Separation Standards

a. ATC effects separation of aircraft vertically by assigning different altitudes; longitudinally by providing

an interval expressed in time or distance between aircraft on the same, converging, or crossing courses, and

laterally by assigning different flight paths.

b. Separation will be provided between all aircraft operating on IFR flight plans except during that part of the

flight (outside Class B airspace or a TRSA) being conducted on a VFR−on−top/VFR conditions clearance. Under

these conditions, ATC may issue traffic advisories, but it is the sole responsibility of the pilot to be vigilant so

as to see and avoid other aircraft.

c. When radar is employed in the separation of aircraft at the same altitude, a minimum of 3 miles separation

is provided between aircraft operating within 40 miles of the radar antenna site, and 5 miles between aircraft

operating beyond 40 miles from the antenna site. These minima may be increased or decreased in certain specific

situations.

NOTE−

Certain separation standards may be increased in the terminal environment due to radar outages or other technical reasons.

4−4−12. Speed Adjustments

a. ATC will issue speed adjustments to pilots of radar controlled aircraft to achieve or maintain appropriate

spacing. If necessary, A TC will assign a speed when approving deviations or radar vectoring off procedures that

include published speed restrictions or a chart note used to transition from Mach to IAS. If no speed is assigned,

speed becomes pilot’s discretion. However, when the aircraft reaches the end of the STAR, the last published

speed on the STAR must be maintained until ATC deletes it, assigns a new speed, issues a vector, assigns a direct

route, or issues an approach clearance.

NOTE−

A chart note identifying a speed to maintain after transitioning from Mach to IAS may be published in lieu of or in addition

to other published speed restrictions on a STAR.

REFERENCE−

AIM, Para 5−4−1, Standard Terminal Arrival (STAR) Procedures

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2/20/25 AIM

b. ATC will express all speed adjustments in terms of knots based on indicated airspeed (IAS) in 5 or 10 knot

increments except that at or above FL 240 speeds may be expressed in terms of Mach numbers in

0.01 increments. The use of Mach numbers is restricted to aircraft with Mach meters.

c. Pilots complying with speed adjustments (published or assigned) are expected to maintain a speed within

plus or minus 10 knots or 0.02 Mach number of the specified speed.

d. When ATC assigns speed adjustments, it will be in accordance with the following recommended

minimums:

1. To aircraft operating between FL 280 and 10,000 feet, a speed not less than 250 knots or the equivalent

Mach number.

NOTE−

1. On a standard day the Mach numbers equivalent to 250 knots CAS (subject to minor variations) are:

FL 240−0.6

FL 250−0.61

FL 260−0.62

FL 270−0.64

FL 280−0.65

FL 290−0.66.

2. When an operational advantage will be realized, speeds lower than the recommended minima may be applied.

2. To arriving turbojet aircraft operating below 10,000 feet:

(a) A speed not less than 210 knots, except;

(b) Within 20 flying miles of the airport of intended landing, a speed not less than 170 knots.

3. To arriving reciprocating engine or turboprop aircraft within 20 flying miles of the runway threshold of

the airport of intended landing, a speed not less than 150 knots.

4. To departing aircraft:

(a) Turbojet aircraft, a speed not less than 230 knots.

(b) Reciprocating engine aircraft, a speed not less than 150 knots.

e. When A TC combines a speed adjustment with a descent clearance, the sequence of delivery, with the word

“then” between, indicates the expected order of execution.

EXAMPLE−

1. Descend and maintain (altitude); then, reduce speed to (speed).

2. Reduce speed to (speed); then, descend and maintain (altitude).

NOTE−

The maximum speeds below 10,000 feet as established in 14 CFR section 91.117 still apply. If there is any doubt concerning

the manner in which such a clearance is to be executed, request clarification from ATC.

f. If ATC determines (before an approach clearance is issued) that it is no longer necessary to apply speed

adjustment procedures, they will:

1. Advise the pilot to “resume normal speed.” Normal speed is used to terminate ATC assigned speed

adjustments on segments where no published speed restrictions apply. It does not cancel published restrictions

on upcoming procedures. This does not relieve the pilot of those speed restrictions which are applicable to

14 CFR section 91.117.

EXAMPLE−

(An aircraft is flying a SID with no published speed restrictions. ATC issues a speed adjustment and instructs the aircraft

where the adjustment ends): “Maintain two two zero knots until BALTR then resume normal speed.”

NOTE−

The ATC assigned speed assignment of two two zero knots would apply until BALTR. The aircraft would then resume a

normal operating speed while remaining in compliance with 14 CFR section 91.117.

ATC Clearances and Aircraft Separation 4−4−9

AIM 2/20/25

2. Instruct pilots to “comply with speed restrictions” when the aircraft is joining or resuming a charted

procedure or route with published speed restrictions.

EXAMPLE−

(ATC vectors an aircraft off of a SID to rejoin the procedure at a subsequent waypoint. When instructing the aircraft to resume

the procedure, ATC also wants the aircraft to comply with the published procedure speed restrictions): “Resume the SALTY

ONE departure. Comply with speed restrictions.”

CAUTION−

The phraseology “Descend via/Climb via SID” requires compliance with all altitude and/or speed restrictions depicted on

the procedure.

3. Instruct the pilot to “resume published speed.” Resume published speed is issued to terminate a speed

adjustment where speed restrictions are published on a charted procedure.

NOTE−

When instructed to “comply with speed restrictions” or to “resume published speed,” ATC anticipates pilots will begin

adjusting speed the minimum distance necessary prior to a published speed restriction so as to cross the waypoint/fix at the

published speed. Once at the published speed, ATC expects pilots will maintain the published speed until additional

adjustment is required to comply with further published or ATC assigned speed restrictions or as required to ensure

compliance with 14 CFR section 91.117.

EXAMPLE−

(An aircraft is flying a SID/STAR with published speed restrictions. ATC issues a speed adjustment and instructs the aircraft

where the adjustment ends): “Maintain two two zero knots until BALTR then resume published speed.”

NOTE−

The ATC assigned speed assignment of two two zero knots would apply until BALTR. The aircraft would then comply with

the published speed restrictions.

4. Advise the pilot to “delete speed restrictions” when either ATC assigned or published speed restrictions

on a charted procedure are no longer required.

EXAMPLE−

(An aircraft is flying a SID with published speed restrictions designed to prevent aircraft overtake on departure. ATC

determines there is no conflicting traffic and deletes the speed restriction): “Delete speed restrictions.”

NOTE−

When deleting published restrictions, ATC must ensure obstacle clearance until aircraft are established on a route where

no published restrictions apply. This does not relieve the pilot of those speed restrictions which are applicable to 14 CFR

section 91.117.

5. Instruct the pilot to “climb via” or “descend via.” A climb via or descend via clearance cancels any

previously issued speed restrictions and, once established on the depicted departure or arrival, to climb or

descend, and to meet all published or assigned altitude and/or speed restrictions.

EXAMPLE−

1. (An aircraft is flying a SID with published speed restrictions. ATC has issued a speed restriction of 250 knots for spacing.

ATC determines that spacing between aircraft is adequate and desires the aircraft to comply with published restrictions):

“United 436, Climb via SID.”

2. (An aircraft is established on a STAR. ATC must slow an aircraft for the purposes of spacing and assigns it a speed of

280 knots. When spacing is adequate, ATC deletes the speed restriction and desires that the aircraft comply with all published

restrictions on the STAR): “Gulfstream two three papa echo, descend via the TYLER One arrival.”

NOTE−

1. In example 1, when ATC issues a “Climb via SID” clearance, it deletes any previously issued speed and/or altitude

restrictions. The pilot should then vertically navigate to comply with all speed and/or altitude restrictions published on the

SID.

2. In example 2, when ATC issues a “Descend via <STAR name> arrival,” ATC has canceled any previously issued speed

and/or altitude restrictions. The pilot should vertically navigate to comply with all speed and/or altitude restrictions

published on the STAR.

4−4−10 ATC Clearances and Aircraft Separation

2/20/25 AIM

CAUTION−

When descending on a STAR, pilots should not speed up excessively beyond the previously issued speed. Otherwise, adequate

spacing between aircraft descending on the STAR that was established by ATC with the previous restriction may be lost.

g. Approach clearances supersede any prior speed adjustment assignments, and pilots are expected to make

their own speed adjustments as necessary to complete the approach. However, under certain circumstances, it

may be necessary for ATC to issue further speed adjustments after approach clearance is issued to maintain

separation between successive arrivals. Under such circumstances, previously issued speed adjustments will be

restated if that speed is to be maintained or additional speed adjustments are requested. Speed adjustments should

not be assigned inside the final approach fix on final or a point 5 miles from the runway, whichever is closer to

the runway.

h. The pilots retain the prerogative of rejecting the application of speed adjustment by ATC if the minimum

safe airspeed for any particular operation is greater than the speed adjustment.

NOTE−

In such cases, pilots are expected to advise ATC of the speed that will be used.

i. Pilots are reminded that they are responsible for rejecting the application of speed adjustment by ATC if,

in their opinion, it will cause them to exceed the maximum indicated airspeed prescribed by 14 CFR

section 91.117(a), (c) and (d). IN SUCH CASES, THE PILOT IS EXPECTED TO SO INFORM ATC. Pilots

operating at or above 10,000 feet MSL who are issued speed adjustments which exceed 250 knots IAS and are

subsequently cleared below 10,000 feet MSL are expected to comply with 14 CFR section 91.117(a).

j. Speed restrictions of 250 knots do not apply to U.S. registered aircraft operating beyond 12 nautical miles

from the coastline within the U.S. Flight Information Region, in Class E airspace below 10,000 feet MSL.

However, in airspace underlying a Class B airspace area designated for an airport, or in a VFR corridor designated

through such as a Class B airspace area, pilots are expected to comply with the 200 knot speed limit specified

in 14 CFR section 91.117(c).

k. For operations in a Class C and Class D surface area, ATC is authorized to request or approve a speed

greater than the maximum indicated airspeeds prescribed for operation within that airspace (14 CFR section

91.117(b)).

NOTE−

Pilots are expected to comply with the maximum speed of 200 knots when operating beneath Class B airspace or in a Class

B VFR corridor (14 CFR section 91.117(c) and (d)).

l. When in communications with the ARTCC or approach control facility, pilots should, as a good operating

practice, state any ATC assigned speed restriction on initial radio contact associated with an ATC

communications frequency change.

4−4−13. Runway Separation

Tower controllers establish the sequence of arriving and departing aircraft by requiring them to adjust flight or

ground operation as necessary to achieve proper spacing. They may “HOLD” an aircraft short of the runway to

achieve spacing between it and an arriving aircraft; the controller may instruct a pilot to “EXTEND

DOWNWIND” in order to establish spacing from an arriving or departing aircraft. At times a clearance may

include the word “IMMEDIATE.” For example: “CLEARED FOR IMMEDIATE TAKEOFF.” In such cases

“IMMEDIATE” is used for purposes of air traffic separation. It is up to the pilot to refuse the clearance if, in

the pilot’s opinion, compliance would adversely affect the operation.

REFERENCE−

AIM, Para 4−3−15, Gate Holding due to Departure Delays.

4−4−14. Visual Separation

a. Visual separation is a means employed by ATC to separate aircraft in terminal areas and en route airspace

in the NAS. There are two methods employed to effect this separation:

ATC Clearances and Aircraft Separation 4−4−11

AIM 2/20/25

1. The tower controller sees the aircraft involved and issues instructions, as necessary, to ensure that the

aircraft avoid each other.

2. A pilot sees the other aircraft involved and upon instructions from the controller provides separation by

maneuvering the aircraft to avoid it. When pilots accept responsibility to maintain visual separation, they must

maintain constant visual surveillance and not pass the other aircraft until it is no longer a factor.

NOTE−

Traffic is no longer a factor when during approach phase the other aircraft is in the landing phase of flight or executes a

missed approach; and during departure or en route, when the other aircraft turns away or is on a diverging course.

b. A pilot’s acceptance of instructions to follow another aircraft or provide visual separation from it is an

acknowledgment that the pilot will maneuver the aircraft as necessary to avoid the other aircraft or to maintain

in−trail separation. In operations conducted behind heavy aircraft, or a small aircraft behind a B757 or other large

aircraft, it is also an acknowledgment that the pilot accepts the responsibility for wake turbulence separation.

Visual separation is prohibited behind super aircraft.

NOTE−

When a pilot has been told to follow another aircraft or to provide visual separation from it, the pilot should promptly notify

the controller if visual contact with the other aircraft is lost or cannot be maintained or if the pilot cannot accept the

responsibility for the separation for any reason.

c. Scanning the sky for other aircraft is a key factor in collision avoidance. Pilots and copilots (or the right

seat passenger) should continuously scan to cover all areas of the sky visible from the cockpit. Pilots must

develop an effective scanning technique which maximizes one’s visual capabilities. Spotting a potential collision

threat increases directly as more time is spent looking outside the aircraft. One must use timesharing techniques

to effectively scan the surrounding airspace while monitoring instruments as well.

d. Since the eye can focus only on a narrow viewing area, effective scanning is accomplished with a series

of short, regularly spaced eye movements that bring successive areas of the sky into the central visual field. Each

movement should not exceed ten degrees, and each area should be observed for at least one second to enable

collision detection. Although many pilots seem to prefer the method of horizontal back −and−forth scanning

every pilot should develop a scanning pattern that is not only comfortable but assures optimum effectiveness.

Pilots should remember, however, that they have a regulatory responsibility (14 CFR section 91.113(a)) to see

and avoid other aircraft when weather conditions permit.

4−4−15. Use of Visual Clearing Procedures and Scanning Techniques

a. Before T akeoff. Prior to taxiing onto a runway or landing area in preparation for takeoff, pilots should scan

the approach areas for possible landing traffic and execute the appropriate clearing maneuvers to provide them

a clear view of the approach areas.

b. Climbs and Descents. During climbs and descents in flight conditions which permit visual detection of

other traffic, pilots should execute gentle banks, left and right at a frequency which permits continuous visual

scanning of the airspace about them.

c. Straight and Level. Sustained periods of straight and level flight in conditions which permit visual

detection of other traffic should be broken at intervals with appropriate clearing procedures to provide effective

visual scanning.

d. Traffic Pattern. Entries into traffic patterns while descending create specific collision hazards and should

be avoided.

e. Traffic at VOR Sites. All operators should emphasize the need for sustained vigilance in the vicinity of

VORs and airway intersections due to the convergence of traffic.

f. Training Operations. Operators of pilot training programs are urged to adopt the following practices:

1. Pilots undergoing flight instruction at all levels should be requested to verbalize clearing procedures (call

out “clear” left, right, above, or below) to instill and sustain the habit of vigilance during maneuvering.

4−4−12 ATC Clearances and Aircraft Separation

2/20/25 AIM

2. High−wing airplane. Momentarily raise the wing in the direction of the intended turn and look.

3. Low−wing airplane. Momentarily lower the wing in the direction of the intended turn and look.

4. Appropriate clearing procedures should precede the execution of all turns including chandelles, lazy

eights, stalls, slow flight, climbs, straight and level, spins, and other combination maneuvers.

g. Scanning Techniques for Traffic Avoidance.

1. Pilots must be aware of the limitations inherent in the visual scanning process. These limitations may

include:

(a) Reduced scan frequency due to concentration on flight instruments or tablets and distraction with

passengers.

(b) Blind spots related to high−wing and low−wing aircraft in addition to windshield posts and sun visors.

(c) Prevailing weather conditions including reduced visibility and the position of the sun.

(d) The attitude of the aircraft will create additional blind spots.

(e) The physical limitations of the human eye, including the time required to (re)focus on near and far

objects, from the instruments to the horizon for example; empty field myopia, narrow field of vision and

atmospheric lighting all affect our ability to detect another aircraft.

2. Best practices to see and avoid:

(a) ADS−B In is an effective system to help pilots see and avoid other aircraft. If your aircraft is equipped

with ADS−B In, it is important to understand its features and how to use it properly. Many units provide visual

and/or audio alerts to supplement the system’s traffic display. Pilots should incorporate the traffic display in their

normal traffic scan to provide awareness of nearby aircraft. Prior to entering or crossing any runway, ADS−B

In can provide advance indication of arriving aircraft and aircraft in the traffic pattern. Systems that incorporate

a traffic−alerting feature can help minimize the pilot’s inclination to fixate on the display. Refer to 4−5−7e,

ADS−B Limitations.

(b) Understand the limitations of ADS−B In. In certain airspace, not all aircraft will be equipped with

ADS−B Out or transponders and will not be visible on your ADS−B In display.

(c) Limit the amount of time that you focus on flight instruments or tablets.

(d) Develop a strategic approach to scanning for traffic. Scan the entire sky and try not to focus straight

ahead.

4−4−16. Traffic Alert and Collision Avoidance System (TCAS I & II)

a. TCAS I provides proximity warning only, to assist the pilot in the visual acquisition of intruder aircraft.

No recommended avoidance maneuvers are provided nor authorized as a direct result of a TCAS I warning. It

is intended for use by smaller commuter aircraft holding 10 to 30 passenger seats, and general aviation aircraft.

b. TCAS II provides traffic advisories (TA) and resolution advisories (RA). Resolution advisories provide

recommended maneuvers in a vertical direction (climb or descend only) to avoid conflicting traffic. Transport

category aircraft, and larger commuter and business aircraft holding 31 passenger seats or more, are required to

be TCAS II equipped.

1. When a TA occurs, attempt to establish visual contact with the traffic but do not deviate from an assigned

clearance based only on TA information.

2. When an RA occurs, pilots should respond immediately to the RA displays and maneuver as indicated

unless doing so would jeopardize the safe operation of the flight, or the flight crew can ensure separation with

the help of definitive visual acquisition of the aircraft causing the RA.

3. Each pilot who deviates from an A TC clearance in response to an RA must notify ATC of that deviation

as soon as practicable, and notify ATC when clear of conflict and returning to their previously assigned clearance.

ATC Clearances and Aircraft Separation 4−4−13

AIM 2/20/25

c. Deviations from rules, policies, or clearances should be kept to the minimum necessary to satisfy an RA.

Most RA maneuvering requires minimum excursion from assigned altitude.

d. The serving IFR air traffic facility is not responsible to provide approved standard IFR separation to an IFR

aircraft, from other aircraft, terrain, or obstructions after an RA maneuver until one of the following conditions

exists:

1. The aircraft has returned to its assigned altitude and course.

2. Alternate ATC instructions have been issued.

3. A crew member informs ATC that the TCAS maneuver has been completed.

NOTE−

TCAS does not alter or diminish the pilot’ s basic authority and responsibility to ensure safe flight. Since TCAS does not

respond to aircraft which are not transponder equipped or aircraft with a transponder failure, TCAS alone does not ensure

safe separation in every case. At this time, no air traffic service nor handling is predicated on the availability of TCAS

equipment in the aircraft.

4−4−17. Traffic Information Service (TIS)

a. TIS provides proximity warning only, to assist the pilot in the visual acquisition of intruder aircraft. No

recommended avoidance maneuvers are provided nor authorized as a direct result of a TIS intruder display or

TIS alert. It is intended for use by aircraft in which TCAS is not required.

b. TIS does not alter or diminish the pilot’s basic authority and responsibility to ensure safe flight. Since TIS

does not respond to aircraft which are not transponder equipped, aircraft with a transponder failure, or aircraft

out of radar coverage, TIS alone does not ensure safe separation in every case.

c. At this time, no air traffic service nor handling is predicated on the availability of TIS equipment in the

aircraft.

d. Presently, no air traffic services or handling is predicated on the availability of an ADS−B cockpit display.

A “traffic−in−sight” reply to ATC must be based on seeing an aircraft out−the−window, NOT on the cockpit

display.

4−4−14 ATC Clearances and Aircraft Separation

2/20/25 AIM

Section 5. Surveillance Systems

4−5−1. Radar

a. Capabilities

1. Radar is a method whereby radio waves are transmitted into the air and are then received when they have

been reflected by an object in the path of the beam. Range is determined by measuring the time it takes (at the

speed of light) for the radio wave to go out to the object and then return to the receiving antenna. The direction

of a detected object from a radar site is determined by the position of the rotating antenna when the reflected

portion of the radio wave is received.

2. More reliable maintenance and improved equipment have reduced radar system failures to a negligible

factor. Most facilities actually have some components duplicated, one operating and another which immediately

takes over when a malfunction occurs to the primary component.

b. Limitations

1. It is very important for the aviation community to recognize the fact that there are limitations to radar

service and that ATC controllers may not always be able to issue traffic advisories concerning aircraft which are

not under ATC control and cannot be seen on radar. (See FIG 4−5−1.)

FIG 4−5−1

Limitations to Radar Service

Precipitation Attenuation

AREA BLACKED OUT

BY ATTENUATION

NOT OBSERVED

OBSERVED

ECHO

The nearby target absorbs and scatters so much of the out-going and returning

energy that the radar does not detect the distant target.

(a) The characteristics of radio waves are such that they normally travel in a continuous straight line

unless they are:

(1) “Bent” by abnormal atmospheric phenomena such as temperature inversions;

(2) Reflected or attenuated by dense objects such as heavy clouds, precipitation, ground obstacles,

mountains, etc.; or

(3) Screened by high terrain features.

(b) The bending of radar pulses, often called anomalous propagation or ducting, may cause many

extraneous blips to appear on the radar operator’s display if the beam has been bent toward the ground or may

decrease the detection range if the wave is bent upward. It is difficult to solve the effects of anomalous

propagation, but using beacon radar and electronically eliminating stationary and slow moving targets by a

method called moving target indicator (MTI) usually negate the problem.

Surveillance Systems 4−5−1

AIM 2/20/25

(c) Radar energy that strikes dense objects will be reflected and displayed on the operator’s scope thereby

blocking out aircraft at the same range and greatly weakening or completely eliminating the display of targets

at a greater range. Again, radar beacon and MTI are very effectively used to combat ground clutter and weather

phenomena, and a method of circularly polarizing the radar beam will eliminate some weather returns. A

negative characteristic of MTI is that an aircraft flying a speed that coincides with the canceling signal of the MTI

(tangential or “blind” speed) may not be displayed to the radar controller.

(d) Relatively low altitude aircraft will not be seen if they are screened by mountains or are below the

radar beam due to earth curvature. The historical solution to screening has been the installation of strategically

placed multiple radars, which has been done in some areas, but ADS−B now provides ATC surveillance in some

areas with challenging terrain where multiple radar installations would be impractical.

(e) There are several other factors which affect radar control. The amount of reflective surface of an

aircraft will determine the size of the radar return. Therefore, a small light airplane or a sleek jet fighter will be

more difficult to see on primary radar than a large commercial jet or military bomber. Here again, the use of

transponder or ADS−B equipment is invaluable. In addition, all FAA ATC facilities display automatically

reported altitude information to the controller from appropriately equipped aircraft.

(f) At some locations within the ATC en route environment, secondary−radar−only (no primary radar)

gap filler radar systems are used to give lower altitude radar coverage between two larger radar systems, each

of which provides both primary and secondary radar coverage. ADS−B serves this same role, supplementing both

primary and secondary radar. In those geographical areas served by secondary radar only or ADS−B, aircraft

without either transponders or ADS −B equipment cannot be provided with radar service. Additionally,

transponder or ADS−B equipped aircraft cannot be provided with radar advisories concerning primary targets

and ATC radar−derived weather.

REFERENCE−

Pilot/Controller Glossary Term− Radar.

(g) With regard to air traffic radar reception, wind turbines generally do not affect the quality of air traffic

surveillance radar returns for transponder and ADS−B Out equipped aircraft. Air traffic interference issues apply

to the search radar and Non−Transponder/Non−ADS−B Out equipped aircraft.

NOTE−

Generally, one or two wind turbines don’t present a significant radar reception loss. A rule of thumb is three (3) or more

turbines constitute a wind turbine farm and thus negatively affect the search radar product.

(1) Detection loss in the area of a wind turbine farm is substantial. In extreme circumstances, this can

extend for more than 1.0 nautical mile (NM) horizontally around the nearest turbine and at all altitudes above

the wind turbine farm. (See FIG 4−5−2.)

FIG 4−5−2

Wind Turbine Farm Area of Potential Interference

4−5−2 Surveillance Systems

2/20/25 AIM

NOTE−

All aircraft should comply with 14 CFR §91.119(c) “…aircraft may not be operated closer than 500 feet to any person,

vessel, vehicle, or structure.”

(2) To avoid interference Non−Transponder/Non−ADS−B Out equipped aircraft should avoid flight

within 1.0 NM horizontally, at all altitudes, from the wind turbine farms.

(3) Because detection loss near and above wind turbine farms for search−only targets causes dropped

tracks, erroneous tracks, and can result in loss of separation, it is imperative that Non−Transponder/Non−ADS−B

Out equipped aircraft operate at the proper VFR altitudes per hemispheric rule and utilize see −and−avoid

techniques.

(4) Pilots should be aware that air traffic controllers cannot provide separation from

Non−Transponder/Non−ADS−B Out equipped aircraft in the vicinity of wind turbine farms. See−and−avoid is

the pilot’s responsibility, as these non−equipped aircraft may not appear on radar and will not appear on the

Traffic Information Services−Broadcast (TIS−B).

(h) The controller’s ability to advise a pilot flying on instruments or in visual conditions of the aircraft’s

proximity to another aircraft will be limited if the unknown aircraft is not observed on radar, if no flight plan

information is available, or if the volume of traffic and workload prevent issuing traffic information. The

controller’s first priority is given to establishing vertical, lateral, or longitudinal separation between aircraft

flying IFR under the control of ATC.

c. FAA radar units operate continuously at the locations shown in the Chart Supplement, and their services

are available to all pilots, both civil and military. Contact the associated FAA control tower or ARTCC on any

frequency guarded for initial instructions, or in an emergency, any FAA facility for information on the nearest

radar service.

4−5−2. Air Traffic Control Radar Beacon System (ATCRBS)

a. The A TCRBS, sometimes referred to as secondary surveillance radar, consists of three main components:

1. Interrogator. Primary radar relies on a signal being transmitted from the radar antenna site and for this

signal to be reflected or “bounced back” from an object (such as an aircraft). This reflected signal is then

displayed as a “target” on the controller’s radarscope. In the ATCRBS, the Interrogator, a ground based radar

beacon transmitter−receiver, scans in synchronism with the primary radar and transmits discrete radio signals

which repetitiously request all transponders, on the mode being used, to reply. The replies received are then

mixed with the primary returns and both are displayed on the same radarscope.

2. Transponder. This airborne radar beacon transmitter−receiver automatically receives the signals from

the interrogator and selectively replies with a specific pulse group (code) only to those interrogations being

received on the mode to which it is set. These replies are independent of, and much stronger than a primary radar

return.

3. Radarscope. The radarscope used by the controller displays returns from both the primary radar system

and the ATCRBS. These returns, called targets, are what the controller refers to in the control and separation of

traffic.

b. The job of identifying and maintaining identification of primary radar targets is a long and tedious task for

the controller. Some of the advantages of ATCRBS over primary radar are:

1. Reinforcement of radar targets.

2. Rapid target identification.

3. Unique display of selected codes.

c. A part of the ATCRBS ground equipment is the decoder. This equipment enables a controller to assign

discrete transponder codes to each aircraft under his/her control. Normally only one code will be assigned for

Surveillance Systems 4−5−3

AIM 2/20/253/15/077110.65R CHG 2AIM 8/7/25

the entire flight. Assignments are made by the ARTCC computer on the basis of the National Beacon Code

Allocation Plan. The equipment is also designed to receive Mode C altitude information from the aircraft.

d. It should be emphasized that aircraft transponders greatly improve the effectiveness of radar systems.

REFERENCE−

AIM, Para 4−1−20, Transponder and ADS−B Out Operation.

4−5−3. Surveillance Radar

a. Surveillance radars are divided into two general categories: Airport Surveillance Radar (ASR) and Air

Route Surveillance Radar (ARSR).

1. ASR is designed to provide relatively short−range coverage in the general vicinity of an airport and to

serve as an expeditious means of handling terminal area traffic through observation of precise aircraft locations

on a radarscope. The ASR can also be used as an instrument approach aid.

2. ARSR is a long−range radar system designed primarily to provide a display of aircraft locations over

large areas.

b. Surveillance radars scan through 360 degrees of azimuth and present target information on a radar display

located in a tower or center. This information is used independently or in conjunction with other navigational

aids in the control of air traffic.

4−5−4. Precision Approach Radar (PAR)

a. PAR is designed for use as a landing aid rather than an aid for sequencing and spacing aircraft. PAR

equipment may be used as a primary landing aid (See Chapter 5, Air Traffic Procedures, for additional

information), or it may be used to monitor other types of approaches. It is designed to display range, azimuth,

and elevation information.

b. Two antennas are used in the PAR array, one scanning a vertical plane, and the other scanning horizontally.

Since the range is limited to 10 miles, azimuth to 20 degrees, and elevation to 7 degrees, only the final approach

area is covered. Each scope is divided into two parts. The upper half presents altitude and distance information,

and the lower half presents azimuth and distance.

4−5−5. Airport Surface Detection Equipment (ASDE−X)/Airport Surface Surveillance

Capability (ASSC)

a. ASDE−X/ASSC is a multi−sensor surface surveillance system the FAA has acquired for airports in the

United States. This system provides high resolution, short −range, clutter free surveillance information about

aircraft and vehicles, both moving and fixed, located on or near the surface of the airport’s runways and taxiways

under all weather and visibility conditions. The system consists of:

1. A Primary Radar System. ASDE−X/ASSC system coverage includes the airport surface and the

airspace up to 200 feet above the surface. Typically located on the control tower or other strategic location on

the airport, the Primary Radar antenna is able to detect and display aircraft that are not equipped with or have

malfunctioning transponders or ADS−B.

2. Interfaces. ASDE−X/ASSC contains an automation interface for flight identification via all automation

platforms and interfaces with the terminal radar for position information.

3. Automation. A Multi−sensor Data Processor (MSDP) combines all sensor reports into a single target

which is displayed to the air traffic controller.

4. Air Traffic Control Tower Display. A high resolution, color monitor in the control tower cab provides

controllers with a seamless picture of airport operations on the airport surface.

b. The combination of data collected from the multiple sensors ensures that the most accurate information

about aircraft location is received in the tower, thereby increasing surface safety and efficiency.

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2/20/25 AIM

c. The following facilities are operational with ASDE−X:

TBL 4−5−1

BWI Baltimore Washington International

BOS Boston Logan International

BDL Bradley International

MDW Chicago Midway

ORD Chicago O’Hare International

CLT Charlotte Douglas International

DFW Dallas/Fort Worth International

DEN Denver International

DTW Detroit Metro Wayne County

FLL Fort Lauderdale/Hollywood Intl

MKE General Mitchell International

IAH George Bush International

ATL Hartsfield−Jackson Atlanta Intl

HNL Honolulu International

JFK John F. Kennedy International

SNA John Wayne−Orange County

LGA LaGuardia

STL Lambert St. Louis International

LAS Las Vegas Harry Reid International

LAX Los Angeles International

SDF Louisville International

MEM Memphis International

MIA Miami International

MSP Minneapolis St. Paul International

EWR Newark International

MCO Orlando International

PHL Philadelphia International

PHX Phoenix Sky Harbor International

DCA Ronald Reagan Washington National

SAN San Diego International

SLC Salt Lake City International

SEA Seattle−Tacoma International

PVD Theodore Francis Green State

IAD Washington Dulles International

HOU William P. Hobby International

d. The following facilities have been projected to receive ASSC:

TBL 4−5−2

SFO San Francisco International

CLE Cleveland−Hopkins International

MCI Kansas City International

CVG Cincinnati/Northern Kentucky Intl

PDX Portland International

MSY Louis Armstrong New Orleans Intl

PIT Pittsburgh International

ANC Ted Stevens Anchorage International

ADW Joint Base Andrews AFB

4−5−6. Traffic Information Service (TIS)

a. Introduction. The Traffic Information Service (TIS) provides information to the cockpit via data link, that

is similar to VFR radar traffic advisories normally received over voice radio. Among the first FAA−provided data

services, TIS is intended to improve the safety and efficiency of “see and avoid” flight through an automatic

display that informs the pilot of nearby traffic and potential conflict situations. This traffic display is intended

to assist the pilot in visual acquisition of these aircraft. TIS employs an enhanced capability of the terminal Mode

S radar system, which contains the surveillance data, as well as the data link required to “uplink” this information

to suitably−equipped aircraft (known as a TIS “client”). TIS provides estimated position, altitude, altitude trend,

and ground track information for up to 8 intruder aircraft within 7 NM horizontally, +3,500 and −3,000 feet

Surveillance Systems 4−5−5

AIM 2/20/25

vertically of the client aircraft (see FIG 4−5−3, TIS Proximity Coverage V olume). The range of a target reported

at a distance greater than 7 NM only indicates that this target will be a threat within 34 seconds and does not

display a precise distance. TIS will alert the pilot to aircraft (under surveillance of the Mode S radar) that are

estimated to be within 34 seconds of potential collision, regardless of distance or altitude. TIS surveillance data

is derived from the same radar used by ATC; this data is uplinked to the client aircraft on each radar scan

(nominally every 5 seconds).

b. Requirements.

1. In order to use TIS, the client and any intruder aircraft must be equipped with the appropriate cockpit

equipment and fly within the radar coverage of a Mode S radar capable of providing TIS. Typically, this will be

within 55 NM of the sites depicted in FIG 4−5−4, Terminal Mode S Radar Sites. ATC communication is not a

requirement to receive TIS, although it may be required by the particular airspace or flight operations in which

TIS is being used.

FIG 4−5−3

TIS Proximity Coverage Volume

4−5−6 Surveillance Systems

2/20/25 AIM

FIG 4−5−4

Terminal Mode S Radar Sites

Surveillance Systems 4−5−7

AIM 2/20/25

FIG 4−5−5

Traffic Information Service (TIS)

Avionics Block Diagram

4−5−8 Surveillance Systems

2/20/25 AIM

2. The cockpit equipment functionality required by a TIS client aircraft to receive the service consists of

the following (refer to FIG 4−5−5):

(a) Mode S data link transponder with altitude encoder.

(b) Data link applications processor with TIS software installed.

(c) Control−display unit.

(d) Optional equipment includes a digital heading source to correct display errors caused by “crab angle”

and turning maneuvers.

NOTE−

Some of the above functions will likely be combined into single pieces of avionics, such as (a) and (b).

3. To be visible to the TIS client, the intruder aircraft must, at a minimum, have an operating transponder

(Mode A, C or S). All altitude information provided by TIS from intruder aircraft is derived from Mode C reports,

if appropriately equipped.

4. TIS will initially be provided by the terminal Mode S systems that are paired with ASR−9 digital primary

radars. These systems are in locations with the greatest traffic densities, thus will provide the greatest initial

benefit. The remaining terminal Mode S sensors, which are paired with ASR−7 or ASR−8 analog primary radars,

will provide TIS pending modification or relocation of these sites. See FIG 4−5−4, Terminal Mode S Radar Sites,

for site locations. There is no mechanism in place, such as NOTAMs, to provide status update on individual radar

sites since TIS is a nonessential, supplemental information service.

The FAA also operates en route Mode S radars (not illustrated) that rotate once every 12 seconds. These sites

will require additional development of TIS before any possible implementation. There are no plans to implement

TIS in the en route Mode S radars at the present time.

c. Capabilities.

1. TIS provides ground−based surveillance information over the Mode S data link to properly equipped

client aircraft to aid in visual acquisition of proximate air traffic. The actual avionics capability of each

installation will vary and the supplemental handbook material must be consulted prior to using TIS. A maximum

of eight (8) intruder aircraft may be displayed; if more than eight aircraft match intruder parameters, the eight

“most significant” intruders are uplinked. These “most significant” intruders are usually the ones in closest

proximity and/or the greatest threat to the TIS client.

2. TIS, through the Mode S ground sensor, provides the following data on each intruder aircraft:

(a) Relative bearing information in 6−degree increments.

(b) Relative range information in 1/8 NM to 1 NM increments (depending on range).

(c) Relative altitude in 100 −foot increments (within 1,000 feet) or 500− foot increments (from

1,000−3,500 feet) if the intruder aircraft has operating altitude reporting capability.

(d) Estimated intruder ground track in 45−degree increments.

(e) Altitude trend data (level within 500 fpm or climbing/descending >500 fpm) if the intruder aircraft

has operating altitude reporting capability.

(f) Intruder priority as either an “traffic advisory” or “proximate” intruder.

3. When flying from surveillance coverage of one Mode S sensor to another, the transfer of TIS is an

automatic function of the avionics system and requires no action from the pilot.

4. There are a variety of status messages that are provided by either the airborne system or ground

equipment to alert the pilot of high priority intruders and data link system status. These messages include the

following:

(a) Alert. Identifies a potential collision hazard within 34 seconds. This alert may be visual and/or

audible, such as a flashing display symbol or a headset tone. A target is a threat if the time to the closest approach

Surveillance Systems 4−5−9

AIM 2/20/25

in vertical and horizontal coordinates is less than 30 seconds and the closest approach is expected to be within

500 feet vertically and 0.5 nautical miles laterally.

(b) TIS Traffic. TIS traffic data is displayed.

(c) Coasting. The TIS display is more than 6 seconds old. This indicates a missing uplink from the

ground system. When the TIS display information is more than 12 seconds old, the “No Traffic” status will be

indicated.

(d) No Traffic. No intruders meet proximate or alert criteria. This condition may exist when the TIS

system is fully functional or may indicate “coasting” between 12 and 59 seconds old (see (c) above).

(e) TIS Unavailable. The pilot has requested TIS, but no ground system is available. This condition will

also be displayed when TIS uplinks are missing for 60 seconds or more.

(f) TIS Disabled. The pilot has not requested TIS or has disconnected from TIS.

(g) Good−bye. The client aircraft has flown outside of TIS coverage.

NOTE−

Depending on the avionics manufacturer implementation, it is possible that some of these messages will not be directly

available to the pilot.

5. Depending on avionics system design, TIS may be presented to the pilot in a variety of different displays,

including text and/or graphics. V oice annunciation may also be used, either alone or in combination with a visual

display. FIG 4−5−5, Traffic Information Service (TIS), Avionics Block Diagram, shows an example of a TIS

display using symbology similar to the Traffic Alert and Collision Avoidance System (TCAS) installed on most

passenger air carrier/commuter aircraft in the U.S. The small symbol in the center represents the client aircraft

and the display is oriented “track up,” with the 12 o’clock position at the top. The range rings indicate 2 and 5 NM.

Each intruder is depicted by a symbol positioned at the approximate relative bearing and range from the client

aircraft. The circular symbol near the center indicates an “alert” intruder and the diamond symbols indicate

“proximate” intruders.

6. The inset in the lower right corner of FIG 4− 5−5, Traffic Information Service (TIS), Avionics Block

Diagram, shows a possible TIS data block display. The following information is contained in this data block:

(a) The intruder, located approximately four o’clock, three miles, is a “proximate” aircraft and currently

not a collision threat to the client aircraft. This is indicated by the diamond symbol used in this example.

(b) The intruder ground track diverges to the right of the client aircraft, indicated by the small arrow.

(c) The intruder altitude is 700 feet less than or below the client aircraft, indicated by the “−07” located

under the symbol.

(d) The intruder is descending >500 fpm, indicated by the downward arrow next to the “−07” relative

altitude information. The absence of this arrow when an altitude tag is present indicates level flight or a

climb/descent rate less than 500 fpm.

NOTE−

If the intruder did not have an operating altitude encoder (Mode C), the altitude and altitude trend “tags” would have been

omitted.

d. Limitations.

1. TIS is NOT intended to be used as a collision avoidance system and does not relieve the pilot’s

responsibility to “see and avoid” other aircraft (see paragraph 5−5−8, See and Avoid). TIS must not be used for

avoidance maneuvers during IMC or other times when there is no visual contact with the intruder aircraft. TIS

is intended only to assist in visual acquisition of other aircraft in VMC. Avoidance maneuvers are neither

provided nor authorized as a direct result of a TIS intruder display or TIS alert.

2. While TIS is a useful aid to visual traffic avoidance, it has some system limitations that must be fully

understood to ensure proper use. Many of these limitations are inherent in secondary radar surveillance. In other

4−5−10 Surveillance Systems

2/20/25 AIM

words, the information provided by TIS will be no better than that provided to ATC. Other limitations and

anomalies are associated with the TIS predictive algorithm.

(a) Intruder Display Limitations. TIS will only display aircraft with operating transponders installed.

TIS relies on surveillance of the Mode S radar, which is a “secondary surveillance” radar similar to the ATCRBS

described in paragraph 4−5−2.

(b) TIS Client Altitude Reporting Requirement. Altitude reporting is required by the TIS client

aircraft in order to receive TIS. If the altitude encoder is inoperative or disabled, TIS will be unavailable, as TIS

requests will not be honored by the ground system. As such, TIS requires altitude reporting to determine the

Proximity Coverage V olume as indicated in FIG 4−5−3. TIS users must be alert to altitude encoder malfunctions,

as TIS has no mechanism to determine if client altitude reporting is correct. A failure of this nature will cause

erroneous and possibly unpredictable TIS operation. If this malfunction is suspected, confirmation of altitude

reporting with ATC is suggested.

(c) Intruder Altitude Reporting. Intruders without altitude reporting capability will be displayed

without the accompanying altitude tag. Additionally, nonaltitude reporting intruders are assumed to be at the

same altitude as the TIS client for alert computations. This helps to ensure that the pilot will be alerted to all traffic

under radar coverage, but the actual altitude difference may be substantial. Therefore, visual acquisition may be

difficult in this instance.

(d) Coverage Limitations. Since TIS is provided by ground−based, secondary surveillance radar, it is

subject to all limitations of that radar. If an aircraft is not detected by the radar, it cannot be displayed on TIS.

Examples of these limitations are as follows:

(1) TIS will typically be provided within 55 NM of the radars depicted in FIG 4−5−4, Terminal Mode

S Radar Sites. This maximum range can vary by radar site and is always subject to “line of sight” limitations;

the radar and data link signals will be blocked by obstructions, terrain, and curvature of the earth.

(2) TIS will be unavailable at low altitudes in many areas of the country, particularly in mountainous

regions. Also, when flying near the “floor” of radar coverage in a particular area, intruders below the client

aircraft may not be detected by TIS.

(3) TIS will be temporarily disrupted when flying directly over the radar site providing coverage if no

adjacent site assumes the service. A ground−based radar, similar to a VOR or NDB, has a zenith cone, sometimes

referred to as the cone of confusion or cone of silence. This is the area of ambiguity directly above the station

where bearing information is unreliable. The zenith cone setting for TIS is 34 degrees: Any aircraft above that

angle with respect to the radar horizon will lose TIS coverage from that radar until it is below this 34 degree angle.

The aircraft may not actually lose service in areas of multiple radar coverage since an adjacent radar will provide

TIS. If no other TIS−capable radar is available, the “Good−bye” message will be received and TIS terminated

until coverage is resumed.

(e) Intermittent Operations. TIS operation may be intermittent during turns or other maneuvering,

particularly if the transponder system does not include antenna diversity (antenna mounted on the top and bottom

of the aircraft). As in (d) above, TIS is dependent on two −way, “line of sight” communications between the

aircraft and the Mode S radar. Whenever the structure of the client aircraft comes between the transponder

antenna (usually located on the underside of the aircraft) and the ground−based radar antenna, the signal may

be temporarily interrupted.

(f) TIS Predictive Algorithm. TIS information is collected one radar scan prior to the scan during

which the uplink occurs. Therefore, the surveillance information is approximately 5 seconds old. In order to

present the intruders in a “real time” position, TIS uses a “predictive algorithm” in its tracking software. This

algorithm uses track history data to extrapolate intruders to their expected positions consistent with the time of

display in the cockpit. Occasionally, aircraft maneuvering will cause this algorithm to induce errors in the TIS

display. These errors primarily affect relative bearing information; intruder distance and altitude will remain

relatively accurate and may be used to assist in “see and avoid.” Some of the more common examples of these

errors are as follows:

Surveillance Systems 4−5−11

AIM 2/20/25

(1) When client or intruder aircraft maneuver excessively or abruptly, the tracking algorithm will

report incorrect horizontal position until the maneuvering aircraft stabilizes.

(2) When a rapidly closing intruder is on a course that crosses the client at a shallow angle (either

overtaking or head on) and either aircraft abruptly changes course within ¼ NM, TIS will display the intruder

on the opposite side of the client than it actually is.

These are relatively rare occurrences and will be corrected in a few radar scans once the course has stabilized.

(g) Heading/Course Reference. Not all TIS aircraft installations will have onboard heading reference

information. In these installations, aircraft course reference to the TIS display is provided by the Mode S radar.

The radar only determines ground track information and has no indication of the client aircraft heading. In these

installations, all intruder bearing information is referenced to ground track and does not account for wind

correction. Additionally, since ground −based radar will require several scans to determine aircraft course

following a course change, a lag in TIS display orientation (intruder aircraft bearing) will occur. As in (f) above,

intruder distance and altitude are still usable.

(h) Closely−Spaced Intruder Errors. When operating more than 30 NM from the Mode S sensor, TIS

forces any intruder within 3/8 NM of the TIS client to appear at the same horizontal position as the client aircraft.

Without this feature, TIS could display intruders in a manner confusing to the pilot in critical situations (for

example, a closely−spaced intruder that is actually to the right of the client may appear on the TIS display to the

left). At longer distances from the radar, TIS cannot accurately determine relative bearing/distance information

on intruder aircraft that are in close proximity to the client.

Because TIS uses a ground−based, rotating radar for surveillance information, the accuracy of TIS data is

dependent on the distance from the sensor (radar) providing the service. This is much the same phenomenon as

experienced with ground−based navigational aids, such as a VOR. As distance from the radar increases, the

accuracy of surveillance decreases. Since TIS does not inform the pilot of distance from the Mode S radar, the

pilot must assume that any intruder appearing at the same position as the client aircraft may actually be up to 3/8

NM away in any direction. Consistent with the operation of TIS, an alert on the display (regardless of distance

from the radar) should stimulate an outside visual scan, intruder acquisition, and traffic avoidance based on

outside reference.

e. Reports of TIS Malfunctions.

1. Users of TIS can render valuable assistance in the early correction of malfunctions by reporting their

observations of undesirable performance. Reporters should identify the time of observation, location, type and

identity of aircraft, and describe the condition observed; the type of transponder processor, and software in use

can also be useful information. Since TIS performance is monitored by maintenance personnel rather than ATC,

it is suggested that malfunctions be reported by radio or telephone to the nearest Flight Service Station (FSS)

facility.

NOTE−

TIS operates at only those terminal Mode S radar sites depicted in FIG 4−5−4. Though similar in some ways, TIS is not

related to TIS−B (Traffic Information Service−Broadcast).

4−5−7. Automatic Dependent Surveillance −Broadcast (ADS−B) Services

a. Introduction.

1. Automatic Dependent Surveillance −Broadcast (ADS −B) is a surveillance technology deployed

throughout the NAS (see FIG 4− 5−6). The ADS−B system is composed of aircraft avionics and a ground

infrastructure. Onboard avionics determine the position of the aircraft by using the GNSS and transmit its

position along with additional information about the aircraft to ground stations for use by ATC and other ADS−B

services. This information is transmitted at a rate of approximately once per second. (See FIG 4−5−7 and

FIG 4−5−8.)

2. In the United States, ADS−B equipped aircraft exchange information on one of two frequencies: 978 or

1090 MHz. The 1090 MHz frequency is also associated with Mode A, C, and S transponder operations. 1090

4−5−12 Surveillance Systems

2/20/25 AIM

MHz transponders with integrated ADS−B functionality extend the transponder message sets with additional

ADS−B information. This additional information is known as an “extended squitter” message and is referred to

as 1090ES. ADS−B equipment operating on 978 MHz is known as the Universal Access Transceiver (UAT).

3. ADS−B avionics can have the ability to both transmit and receive information. The transmission of

ADS−B information from an aircraft is known as ADS−B Out. The receipt of ADS−B information by an aircraft

is known as ADS−B In. All aircraft operating within the airspace defined in 14 CFR § 91.225 are required to

transmit the information defined in § 91.227 using ADS−B Out avionics.

4. In general, operators flying at 18,000 feet and above (Class A airspace) are required to have 1090ES

equipment. Those that do not fly above 18,000 may use either UAT or 1090ES equipment. (Refer to 14 CFR §§

91.225 and 91.227.) While the regulations do not require it, operators equipped with ADS −B In will realize

additional benefits from ADS− B broadcast services: Traffic Information Service – Broadcast (TIS −B)

(paragraph 4−5−8) and Flight Information Service − Broadcast (FIS−B) (paragraph 4−5−9).

FIG 4−5−6

ADS−B, TIS−B, and FIS−B:

Broadcast Services Architecture

b. ADS−B Certification and Performance Requirements.

ADS−B equipment may be certified as a surveillance source for air traffic separation services using ADS−B Out.

ADS−B equipment may also be certified for use with ADS −B In advisory services that enable appropriately

equipped aircraft to display traffic and flight information. Refer to the aircraft’s flight manual supplement or Pilot

Operating Handbook for the capabilities of a specific aircraft installation.

c. ADS−B Capabilities and Procedures.

1. ADS−B enables improved surveillance services, both air−to−air and air−to−ground, especially in areas

where radar is ineffective due to terrain or where it is impractical or cost prohibitive. Initial NAS applications

Surveillance Systems 4−5−13

AIM 2/20/25

of air−to−air ADS−B are for “advisory” use only, enhancing a pilot’s visual acquisition of other nearby equipped

aircraft either when airborne or on the airport surface. Additionally, ADS−B will enable ATC and fleet operators

to monitor aircraft throughout the available ground station coverage area.

FIG 4−5−7

En Route − ADS−B/ADS−R/TIS−B/FIS−B Service Ceilings/Floors

FIG 4−5−8

Terminal − ADS−B/ADS−R/TIS−B/FIS−B Service Ceilings/Floors

2. One of the data elements transmitted by ADS−B is the aircraft’s Flight Identification (FLT ID). The FLT

ID is comprised of a maximum of seven alphanumeric characters and must correspond to the aircraft

identification filed in the flight plan. For airline and commuter aircraft, the FLT ID is usually the company name

and flight number (for example, AAL3432), and is typically entered into the avionics by the flight crew during

preflight. For general aviation (GA), if aircraft avionics allow dynamic modification of the FLT ID, the pilot can

4−5−14 Surveillance Systems

2/20/25 AIM

enter it prior to flight. However, some ADS−B avionics require the FLT ID to be set to the aircraft registration

number (for example, N1234Q) by the installer and cannot be changed by the pilot from the cockpit. In both

cases, the FLT ID must correspond to the aircraft identification filed in its flight plan.

ATC automation systems use the transmitted ADS−B FLT ID to uniquely identify each aircraft within a given

airspace, and to correlate it to its filed flight plan for the purpose of providing surveillance and separation

services. If the FLT ID and the filed aircraft identification are not identical, a Call Sign Mis−Match (CSMM) is

generated and ATC automation systems may not associate the aircraft with its filed flight plan. In this case, air

traffic services may be delayed or unavailable until the CSMM is corrected. Consequently, it is imperative that

flight crews and GA pilots ensure the FLT ID entry correctly matches the aircraft identification filed in their flight

plan.

3. Each ADS−B aircraft is assigned a unique ICAO address (also known as a 24 −bit address) that is

broadcast by the ADS−B transmitter. This ICAO address is programmed at installation. Should multiple aircraft

broadcast the same ICAO address while transiting the same ADS−B Only Service V olume, the ADS−B network

may be unable to track the targets correctly. If radar reinforcement is available, tracking will continue. If radar

is unavailable, the controller may lose target tracking entirely on one or both targets. Consequently, it is

imperative that the ICAO address entry is correct.

4. Aircraft that are equipped with ADS−B avionics on the UAT datalink have a feature that allows them to

broadcast an anonymous 24−bit ICAO address. In this mode, the UAT system creates a randomized address that

does not match the actual ICAO address assigned to the aircraft. The UAT anonymous 24−bit address feature

may only be used when the operator has not filed an IFR flight plan and is not requesting ATC services. In the

anonymity mode, the aircraft’s beacon code must be set to 1200 and, depending on the manufacturer’s

implementation, the aircraft FLT ID might not be transmitted. Pilots should be aware that while in UAT

anonymity mode, they will not be eligible to receive ATC separation and flight following services, and may not

benefit from enhanced ADS−B search and rescue capabilities.

5. ADS−B systems integrated with the transponder will automatically set the applicable emergency status

when 7500, 7600, or 7700 are entered into the transponder. ADS−B systems not integrated with the transponder,

or systems with optional emergency codes, will require that the appropriate emergency code is entered through

a pilot interface. ADS−B is intended for inflight and airport surface use. Unless otherwise directed by ATC,

transponder/ADS−B systems should be turned “on” and remain “on” whenever operating in the air or on the

airport surface movement area.

d. ATC Surveillance Services using ADS−B − Procedures and Recommended Phraseology

Radar procedures, with the exceptions found in this paragraph, are identical to those procedures prescribed for

radar in AIM Chapter 4 and Chapter 5.

1. Preflight:

If A TC services are anticipated when either a VFR or IFR flight plan is filed, the aircraft identification (as entered

in the flight plan) must be entered as the FLT ID in the ADS−B avionics.

2. Inflight:

When requesting surveillance services while airborne, pilots must disable the anonymous feature, if so equipped,

prior to contacting ATC. Pilots must also ensure that their transmitted ADS −B FLT ID matches the aircraft

identification as entered in their flight plan.

3. Aircraft with an Inoperative/Malfunctioning ADS−B Transmitter:

(a) ATC will inform the flight crew when the aircraft’s ADS−B transmitter appears to be inoperative or

malfunctioning:

PHRASEOLOGY−

YOUR ADS−B TRANSMITTER APPEARS TO BE INOPERATIVE/MALFUNCTIONING. STOP ADS−B TRANSMISSIONS.

(b) ATC will inform the flight crew if it becomes necessary to turn off the aircraft’s ADS−B transmitter.

Surveillance Systems 4−5−15

AIM 2/20/25

PHRASEOLOGY−

STOP ADS−B TRANSMISSIONS.

(c) Other malfunctions and considerations:

Loss of automatic altitude reporting capabilities (encoder failure) will result in loss of ATC altitude advisory

services.

4. Procedures for Accommodation of Non−ADS−B Equipped Aircraft:

(a) Pilots of aircraft not equipped with ADS−B may only operate outside airspace designated as ADS−B

airspace in 14 CFR §91.225. Pilots of unequipped aircraft wishing to fly any portion of a flight in ADS −B

airspace may seek a deviation from the regulation to conduct operations without the required equipment.

Direction for obtaining this deviation are available in Advisory Circular 90−114.

(b) While air traffic controllers can identify which aircraft are ADS−B equipped and which are not, there

is no indication if a non −equipped pilot has obtained a preflight authorization to enter ADS −B airspace.

Situations may occur when the pilot of a non−equipped aircraft, without an authorization to operate in ADS−B

airspace receives an ATC−initiated in−flight clearance to fly a heading, route, or altitude that would penetrate

ADS−B airspace. Such clearances may be for traffic, weather, or simply to shorten the aircraft’s route of flight.

When this occurs, the pilot should acknowledge and execute the clearance, but must advise the controller that

they are not ADS−B equipped and have not received prior authorization to operate in ADS −B airspace. The

controller, at their discretion, will either acknowledge and proceed with the new clearance, or modify the

clearance to avoid ADS−B airspace. In either case, the FAA will normally not take enforcement action for

non−equipage in these circumstances.

NOTE−

Pilots operating without ADS−B equipment must not request route or altitude changes that will result in an incursion into

ADS−B airspace except for safety of flight; for example, weather avoidance. Unequipped aircraft that have not received a

pre−flight deviation authorization will only be considered in compliance with regulation if the amendment to flight is

initiated by ATC.

EXAMPLE−

1. ATC: “November Two Three Quebec, turn fifteen degrees left, proceed direct Bradford when able, rest of route

unchanged.”

Aircraft: “November Two Three Quebec, turning fifteen degrees left, direct Bradford when able, rest of route unchanged.

Be advised, we are negative ADS−B equipment and have not received authorization to operate in ADS−B airspace.”

ATC: “November Two Three Quebec, roger”

or

“November Two Three Quebec, roger , turn twenty degrees right, rejoin Victor Ten, rest of route unchanged.”

2. ATC: “November Four Alpha Tango, climb and maintain one zero thousand for traffic.”

Aircraft: “November Four Alpha Tango, leaving eight thousand for one zero thousand. Be advised, we are negative ADS−B

equipment and have not received authorization to operate in ADS−B airspace.”

ATC: “November Four Alpha Tango, roger”

or

“November Four Alpha Tango, roger , cancel climb clearance, maintain eight thousand.”

REFERENCE−

Federal Register Notice, Volume 84, Number 62, dated April 1, 2019.

e. ADS−B Limitations.

The ADS−B cockpit display of traffic is NOT intended to be used as a collision avoidance system and does not

relieve the pilot’s responsibility to “see and avoid” other aircraft. (See paragraph 5−5−8, See and Avoid). ADS−B

must not be used for avoidance maneuvers during IMC or other times when there is no visual contact with the

intruder aircraft. ADS−B is intended only to assist in visual acquisition of other aircraft. No avoidance maneuvers

are provided or authorized, as a direct result of an ADS−B target being displayed in the cockpit.

f. Reports of ADS−B Malfunctions.

4−5−16 Surveillance Systems

2/20/25 AIM

Users of ADS−B can provide valuable assistance in the correction of malfunctions by reporting instances of

undesirable system performance. Since ADS−B performance is monitored by maintenance personnel rather than

ATC, report malfunctions to the nearest Flight Service Station (FSS) facility by radio or telephone, or by sending

an email to the ADS−B help desk at [email protected]. Reports should include:

1. Condition observed;

2. Date and time of observation;

3. Altitude and location of observation;

4. Type and call sign of the aircraft; and

5. Type and software version of avionics system.

4−5−8. Traffic Information Service − Broadcast (TIS−B)

a. Introduction

TIS−B is the broadcast of ATC derived traffic information to ADS−B equipped (1090ES or UA T) aircraft from

ground radio stations. The source of this traffic information is derived from ground−based air traffic surveillance

sensors. TIS−B service will be available throughout the NAS where there are both adequate surveillance

coverage from ground sensors and adequate broadcast coverage from ADS−B ground radio stations. The quality

level of traffic information provided by TIS −B is dependent upon the number and type of ground sensors

available as TIS−B sources and the timeliness of the reported data. (See FIG 4−5−7 and FIG 4−5−8.)

b. TIS−B Requirements.

In order to receive TIS−B service, the following conditions must exist:

1. Aircraft must be equipped with an ADS−B transmitter/receiver or transceiver, and a cockpit display of

traffic information (CDTI).

2. Aircraft must fly within the coverage volume of a compatible ground radio station that is configured for

TIS−B uplinks. (Not all ground radio stations provide TIS−B due to a lack of radar coverage or because a radar

feed is not available).

3. Aircraft must be within the coverage of and detected by at least one ATC radar serving the ground radio

station in use.

c. TIS−B Capabilities.

1. TIS−B is intended to provide ADS−B equipped aircraft with a more complete traffic picture in situations

where not all nearby aircraft are equipped with ADS −B Out. This advisory−only application is intended to

enhance a pilot’s visual acquisition of other traffic.

2. Only transponder−equipped targets (i.e., Mode A/C or Mode S transponders) are transmitted through the

ATC ground system architecture. Current radar siting may result in limited radar surveillance coverage at lower

altitudes near some airports, with subsequently limited TIS −B service volume coverage. If there is no radar

coverage in a given area, then there will be no TIS−B coverage in that area.

d. TIS−B Limitations.

1. TIS−B is NOT intended to be used as a collision avoidance system and does not relieve the pilot’s

responsibility to “see and avoid” other aircraft, in accordance with 14CFR §91.113b. TIS−B must not be used

for avoidance maneuvers during times when there is no visual contact with the intruder aircraft. TIS −B is

intended only to assist in the visual acquisition of other aircraft.

NOTE−

No aircraft avoidance maneuvers are authorized as a direct result of a TIS−B target being displayed in the cockpit.

2. While TIS−B is a useful aid to visual traffic avoidance, its inherent system limitations must be understood

to ensure proper use.

Surveillance Systems 4−5−17

AIM 2/20/253/15/077110.65R CHG 2AIM 8/7/25

(a) A pilot may receive an intermittent TIS−B target of themselves, typically when maneuvering (e.g.,

climbing turns) due to the radar not tracking the aircraft as quickly as ADS−B.

(b) The ADS−B−to−radar association process within the ground system may at times have difficulty

correlating an ADS−B report with corresponding radar returns from the same aircraft. When this happens the

pilot may see duplicate traffic symbols (i.e., “TIS−B shadows”) on the cockpit display.

(c) Updates of TIS−B traffic reports will occur less often than ADS−B traffic updates. TIS−B position

updates will occur approximately once every 3−13 seconds depending on the type of radar system in use within

the coverage area. In comparison, the update rate for ADS−B is nominally once per second.

(d) The TIS−B system only uplinks data pertaining to transponder−equipped aircraft. Aircraft without

a transponder will not be displayed as TIS−B traffic.

(e) There is no indication provided when any aircraft is operating inside or outside the TIS −B service

volume, therefore it is difficult to know if one is receiving uplinked TIS−B traffic information.

3. Pilots and operators are reminded that the airborne equipment that displays TIS −B targets is for pilot

situational awareness only and is not approved as a collision avoidance tool. Unless there is an imminent

emergency requiring immediate action, any deviation from an air traffic control clearance in response to

perceived converging traffic appearing on a TIS−B display must be approved by the controlling ATC facility

before commencing the maneuver, except as permitted under certain conditions in 14CFR §91.123.

Uncoordinated deviations may place an aircraft in close proximity to other aircraft under ATC control not seen

on the airborne equipment and may result in a pilot deviation or other incident.

e. Reports of TIS−B Malfunctions.

Users of TIS−B can provide valuable assistance in the correction of malfunctions by reporting instances of

undesirable system performance. Since TIS−B performance is monitored by maintenance personnel rather than

ATC, report malfunctions to the nearest Flight Service Station (FSS) facility by radio or telephone, or by sending

an email to the ADS−B help desk at [email protected]. Reports should include:

1. Condition observed;

2. Date and time of observation;

3. Altitude and location of observation;

4. Type and call sign of the aircraft; and

5. Type and software version of avionics system.

4−5−9. Flight Information Service − Broadcast (FIS−B)

a. Introduction.

FIS−B is a ground broadcast service provided through the ADS−B Services network over the 978 MHz UAT data

link. The FAA FIS−B system provides pilots and flight crews of properly equipped aircraft with a cockpit display

of certain aviation weather and aeronautical information. FIS−B reception is line−of−sight within the service

volume of the ground infrastructure. (See FIG 4−5−7 and FIG 4−5−8.)

b. Weather Products.

FIS-B does not replace a preflight weather briefing from a source listed in paragraph 7 −1−2, FAA Weather

Services, or inflight updates from an FSS or A TC. FIS-B information may be used by the pilot for the safe conduct

of flight and aircraft movement; however, the information should not be the only source of weather or

aeronautical information. A pilot should be particularly alert and understand the limitations and quality assurance

issues associated with individual products. This includes graphical representation of next generation weather

radar (NEXRAD) imagery and Notices to Airmen (NOTAMs)/temporary flight restrictions (TFRs).

REFERENCE−

AIM, Para 7−1−9, Flight Information Services (FIS).

Advisory Circular (AC) 00−63, Use of Cockpit Displays of Digital Weather and Aeronautical Information.

4−5−18 Surveillance Systems

2/20/25 AIM

c. Reports of FIS−B Malfunctions.

Users of FIS−B can provide valuable assistance in the correction of malfunctions by reporting instances of

undesirable system performance. Since FIS−B performance is monitored by maintenance personnel rather than

ATC, report malfunctions to the nearest Flight Service Station (FSS) facility by radio or telephone, or by sending

an email to the ADS−B help desk at [email protected]. Reports should include:

1. Condition observed;

2. Date and time of observation;

3. Altitude and location of observation;

4. Type and call sign of the aircraft; and

5. Type and software version of avionics system.

Surveillance Systems 4−5−19

AIM 2/20/25

TBL 4−5−3

FIS−B Over UAT Product Update and Transmission Intervals

Product Update Interval1 Transmission

Interval (95%)2

Basic

Product

AIRMET As Available 5 minutes Yes

AWW/WW As Available, then at 15 minute

intervals for 1 hour 5 minutes No

Ceiling As Available 10 minutes No

Convective SIGMET As Available, then at 15 minute

intervals for 1 hour 5 minutes Yes

D−A TIS As Available 1 minute No

Echo Top 5 minutes 5 minutes No

METAR/SPECI 1 minute (where available), As

Available otherwise 5 minutes Yes

MRMS NEXRAD (CONUS) 2 minutes 15 minutes Yes

MRMS NEXRAD (Regional) 2 minutes 2.5 minutes Yes

NOTAMs−D/FDC As Available 10 minutes Yes

NOTAMs−TFR As Available 10 minutes Yes

PIREP As Available 10 minutes Yes

SIGMET As Available, then at 15 minute

intervals for 1 hour 5 minutes Yes

SUA Status As Available 10 minutes Yes

TAF/AMEND 6 Hours (±15 minutes) 10 minutes Yes

Temperature Aloft 12 Hours (±15 minutes) 10 minutes Yes

TWIP As Available 1 minute No

Winds aloft 12 Hours (±15 minutes) 10 minutes Yes

Lightning strikes 3 5 minutes 5 minutes Yes

Turbulence 3 1 minute 15 minutes Yes

Icing, Forecast Potential (FIP) 3 60 minutes 15 minutes Yes

Cloud tops 3 30 minutes 15 minutes Yes

1 Minute AWOS 3 1 minute 10 minutes No

Graphical−AIRMET 3 As Available 5 minutes Yes

Center Weather Advisory (CWA) 3 As Available 10 minutes Yes

Temporary Restricted Areas (TRA) As Available 10 minutes Yes

Temporary Military Operations Areas

(TMOA) As Available 10 minutes Yes

1 The Update Interval is the rate at which the product data is available from the source.

2 The Transmission Interval is the amount of time within which a new or updated product transmission must be completed

(95%) and the rate or repetition interval at which the product is rebroadcast (95%).

3 The transmission and update intervals for the expanded set of basic meteorological products may be adjusted based on FAA

and vendor agreement on the final product formats and performance requirements.

4−5−20 Surveillance Systems

2/20/25 AIM

NOTE−

1. Details concerning the content, format, and symbols of the various data link products provided should be obtained from

the specific avionics manufacturer.

2. NOTAM−D and NOTAM−FDC products broadcast via FIS−B are limited to those issued or effective within the past 30

days.

4−5−10. Automatic Dependent Surveillance −Rebroadcast (ADS−R)

a. Introduction.

ADS−R is a datalink translation function of the ADS−B ground system required to accommodate the two separate

operating frequencies (978 MHz and 1090 ES). The ADS−B system receives the ADS−B messages transmitted

on one frequency and ADS−R translates and reformats the information for rebroadcast and use on the other

frequency. This allows ADS−B In equipped aircraft to see nearby ADS−B Out traffic regardless of the operating

link of the other aircraft. Aircraft operating on the same ADS−B frequency exchange information directly and

do not require the ADS−R translation function. (See FIG 4−5−7 and FIG 4−5−8.)

b. Reports of ADS−R Malfunctions.

Users of ADS–R can provide valuable assistance in the correction of malfunctions by reporting instances of

undesirable system performance. Since ADS–R performance is monitored by maintenance personnel rather than

ATC, report malfunctions to the nearest Flight Service Station (FSS) facility by radio or telephone, or by sending

an email to the ADS−B help desk at [email protected]. Reports should include:

1. Condition observed;

2. Date and time of observation;

3. Altitude and location of observation;

4. Type and call sign of the aircraft and;

5. Type and software version of avionics system.

Surveillance Systems 4−5−21

AIM2/20/258/7/25 AIM

Section 6. Operational Policy/Procedures for Reduced

Vertical Separation Minimum (RVSM) in the Domestic

U.S., Alaska, Offshore Airspace and the San Juan FIR

4−6−1. Applicability and RVSM Mandate (Date/Time and Area)

a. Applicability. The policies, guidance and direction in this section apply to RVSM operations in the

airspace over the lower 48 states, Alaska, Atlantic and Gulf of America High Offshore Airspace and airspace

in the San Juan FIR where VHF or UHF voice direct controller −pilot communication (DCPC) is normally

available. Policies, guidance and direction for RVSM operations in oceanic airspace where VHF or UHF voice

DCPC is not available and the airspace of other countries can be found in the Aeronautical Information

Publication (AIP), Part II− En Route, ENR 1. General Rules and Procedures, and ENR 7.Oceanic Operations.

b. Requirement. The FAA implemented RVSM be tween flight level (FL) 290 −410 (inclusive) in the

following airspace: the airspace of the lower 48 states of the United States, Alaska, Atlantic and Gulf of America

High Offshore Airspace and the San Juan FIR. RVSM has been implemented worldwide and may be applied in

all ICAO Flight Information Regions (FIR).

c. RVSM Authorization. In accordance with 14 CFR section 91.180, with only limited exceptions, prior to

operating in RVSM airspace, operators must comply with the standards of part 91, Appendix G, and be authorized

by the Administrator. If either the operator or the operator’s aircraft have not met the applicable RVSM standards,

the aircraft will be referred to as a “non− RVSM” aircraft. Paragraph 4 −6−10 discusses ATC policies for

accommodation of non−RVSM aircraft flown by the Department of Defense, Air Ambulance (MEDEV AC)

operators, foreign State governments and aircraft flown for certification and development. Paragraph 4−6−11,

Non−RVSM Aircraft Requesting Climb to and Descent from Flight Levels Above RVSM Airspace Without

Intermediate Level Off, contains policies for non −RVSM aircraft climbing and descending through RVSM

airspace to/from flight levels above RVSM airspace.

d. Benefits. RVSM enhances ATC flexibility, mitigates conflict points, enhances sector throughput, reduces

controller workload and enables crossing traffic. Operators gain fuel savings and operating efficiency benefits

by flying at more fuel efficient flight levels and on more user preferred routings.

4−6−2. Flight Level Orientation Scheme

Altitude assignments for direction of flight follow a scheme of odd altitude assignment for magnetic courses

000−179 degrees and even altitudes for magnetic courses 180−359 degrees for flights up to and including FL 410,

as indicated in FIG 4−6−1.

Operational Policy/Procedures for Reduced Vertical Separation Minimum (RVSM) in the 4−6−1

Domestic U.S., Alaska, Offshore Airspace and the San Juan FIR

AIM 2/20/25

FIG 4−6−1

Flight Level Orientation Scheme

NOTE−

Odd Flight Levels: Magnetic Course 000−179 Degrees Even Flight Levels: Magnetic Course 180−359 Degrees.

4−6−3. Aircraft and Operator Approval Policy/Procedures, RVSM Monitoring and Databases

for Aircraft and Operator Approval

a. RVSM Authority . 14 CFR section 91.180 applies to RVSM operations within the U.S. 14 CFR

section 91.706 applies to RVSM operations outside the U.S. Both sections require that the operator be authorized

prior to operating in RVSM airspace. For Domestic RVSM operations, an operator may choose to operate under

the provisions of part 91, Appendix G, section 9; or if intending to operate outside U.S. airspace, hold a specific

approval (OpSpec/MSpec/LOA) under the provisions of section 3 of part 91, Appendix G.

b. Sources of Information. Advisory Circular (AC) 91−85, Authorization of Aircraft and Operators for

Flight in Reduced Vertical Separation Minimum (RVSM) Airspace, and the FAA RVSM website.

c. TCAS Equipage. TCAS equipage requirements are contained in 14 CFR sections 121.356, 125.224,

129.18 and 135.189. part 91, Appendix G, does not contain TCAS equipage requirements specific to RVSM,

however, Appendix G does require that aircraft equipped with TCAS II and flown in RVSM airspace be modified

to incorporate TCAS II Version 7.0 or a later version.

d. Aircraft Monitoring. Operators are required to participate in the RVSM altitude−keeping performance

monitoring program that is appropriate for the type of operation being conducted. The monitoring programs

are described in AC 91−85. Monitoring is a quality control program that enables the FAA and other civil aviation

authorities to assess the in−service altitude−keeping performance of aircraft and operators.

e. Purpose of RVSM Approvals Databases. All RVSM designated airspace is monitored airspace. A TC

does not use RVSM approvals databases to determine whether or not a clearance can be issued into RVSM

airspace. RVSM program managers do regularly review the operators and aircraft that operate in RVSM

airspace to identify and investigate those aircraft and operators flying in RVSM airspace, but not listed on the

RVSM approvals databases.

f. Registration of U.S. Operators. When U.S. operators and aircraft are granted specific RVSM authority,

the Separation Standards Group at the FAA Technical Center obtains PTRS operator and aircraft information

to update the FAA maintained U.S. Operator/Aircraft RVSM Approvals database. Basic database operator and

aircraft information can be viewed on the RVSM Documentation web page in the “RVSM Approvals” section.

4−6−2 Operational Policy/Procedures for Reduced Vertical Separation Minimum (RVSM) in the

Domestic U.S., Alaska, Offshore Airspace and the San Juan FIR

2/20/25 AIM

4−6−4. Flight Planning into RVSM Airspace

a. Operators that do not file the correct aircraft equipment suffix on the FAA or ICAO Flight Plan may be

denied clearance into RVSM airspace. Policies for the FAA Flight Plan are detailed in subparagraph c below.

Policies for the ICAO Flight Plan are detailed in subparagraph d.

b. The operator will annotate the equipment block of the FAA or ICAO Flight Plan with an aircraft equipment

suffix indicating RVSM capability only after determining that both the operator is authorized and its aircraft are

RVSM−compliant.

1. An operator may operate in RVSM airspace under the provisions of part 91, Appendix G, section 9,

without specific authorization and should file “/w” in accordance with paragraph d.

2. An operator must get an OpSpec/MSpec/LOA when intending to operate RVSM outside U.S. airspace.

Once issued, that operator can file “/w” in accordance with paragraph d.

3. An operator should not file “/w” when intending to operate in RVSM airspace outside of the U.S., if they

do not hold a valid OpSpec/MSpec/LOA.

c. General Policies for FAA Flight Plan Equipment Suffix. Appendix 4, TBL 4−2, allows operators to indicate

that the aircraft has both RVSM and Advanced Area Navigation (RNA V) capabilities or has only RVSM

capability.

1. The operator will annotate the equipment block of the FAA Flight Plan with the appropriate aircraft

equipment suffix from Appendix 4, TBL 4−2 and/or TBL 4−3.

2. Operators can only file one equipment suffix in block 3 of the FAA Flight Plan. Only this equipment

suffix is displayed directly to the controller.

3. Aircraft with RNA V Capability. For flight in RVSM airspace, aircraft with RNA V capability, but not

Advanced RNA V capability, will file “/W”. Filing “/W” will not preclude such aircraft from filing and flying

direct routes in en route airspace.

d. Policy for ICAO Flight Plan Equipment Suffixes.

1. Operators/aircraft that are RVSM−compliant and that file ICAO flight plans will file “/W” in block 10

(Equipment) to indicate RVSM authorization and will also file the appropriate ICAO Flight Plan suffixes to

indicate navigation and communication capabilities.

2. Operators/aircraft that file ICAO flight plans that include flight in Domestic U.S. RVSM airspace must

file “/W” in block 10 to indicate RVSM authorization.

e. Importance of Flight Plan Equipment Suffixes. Military users, and civilians who file stereo route flight

plans, must file the appropriate equipment suffix in the equipment block of the FAA Form 7233−1, Flight Plan,

or DD Form 175, Military Flight Plan, or FAA Form 7233−4, International Flight Plan, or DD Form 1801, DoD

International Flight Plan. All other users must file the appropriate equipment suffix in the equipment block of

FAA Form 7233−4, International Flight Plan. The equipment suffix informs ATC:

1. Whether or not the operator and aircraft are authorized to fly in RVSM airspace.

2. The navigation and/or transponder capability of the aircraft (e.g., advanced RNA V , transponder with

Mode C).

f. Significant ATC uses of the flight plan equipment suffix information are:

1. To issue or deny clearance into RVSM airspace.

2. To apply a 2,000 foot vertical separation minimum in RVSM airspace to aircraft that are not authorized

for RVSM, but are in one of the limited categories that the FAA has agreed to accommodate. (See paragraphs

4−6−10, Procedures for Accommodation of Non−RVSM Aircraft, and 4−6−11, Non−RVSM Aircraft Requesting

Climb to and Descent from Flight Levels Above RVSM Airspace Without Intermediate Level Off, for policy

on limited operation of unapproved aircraft in RVSM airspace).

Operational Policy/Procedures for Reduced Vertical Separation Minimum (RVSM) in the 4−6−3

Domestic U.S., Alaska, Offshore Airspace and the San Juan FIR

AIM 2/20/25

3. To determine if the aircraft has “Advanced RNA V” capabilities and can be cleared to fly procedures for

which that capability is required.

g. Improperly changing an aircraft equipment suffix and/or adding “NON-RVSM” in the NOTES or

REMARKS section (Field 18) while not removing the “W” from Field 10, will not provide air traffic control with

the proper visual indicator necessary to detect Non-RVSM aircraft. To ensure information processes correctly

for Non-RVSM aircraft, the “W” in Field 10 must be removed. Entry of information in the NOTES or

REMARKS section (Field 18) will not affect the determination of RVSM capability and must not be used to

indicate a flight is Non-RVSM.

4−6−5. Pilot RVSM Operating Practices and Procedures

a. RVSM Mandate. If either the operator is not authorized for RVSM operations or the aircraft is not

RVSM−compliant, the pilot will neither request nor a ccept a clearance into RVSM airspace unless:

1. The flight is conducted by a non−RVSM DoD, MEDEV AC, certification/development or foreign State

(government) aircraft in accordance with paragraph 4−6−10, Procedures for Accommodation of Non−RVSM

Aircraft.

2. The pilot intends to climb to or descend from FL 430 or above in accordance with paragraph 4−6−11,

Non−RVSM Aircraft Requesting Climb to and Descent from Flight Levels Above RVSM Airspace Without

Intermediate Level Off.

3. An emergency situation exists.

b. Basic RVSM Operating Practices and Procedures. AC 91−85 contains pilot practices and procedures

for RVSM. Operators must incorporate applicable practices and procedures, as supplemented by the applicable

paragraphs of this section, into operator training or pilot knowledge programs and operator documents

containing RVSM operational policies.

c. AC 91−85 contains practices and procedures for flight planning, preflight procedures at the aircraft,

procedures prior to RVSM airspace entry, inflight (en route) procedures, contingency procedures and post flight.

d. The following paragraphs either clarify or supplement AC 91−85 practices and procedures.

4−6−6. Guidance on Severe Turbulence and Mountain Wave Activity (MWA)

a. Introduction/Explanation

1. The information and practices in this paragraph are provided to emphasize to pilots and controllers the

importance of taking appropriate action in RVSM airspace when aircraft experience severe turbulence and/or

MWA that is of sufficient magnitude to significantly affect altitude−keeping.

2. Severe Turbulence. Severe turbulence causes large, abrupt changes in altitude and/or attitude usually

accompanied by large variations in indicated airspeed. Aircraft may be momentarily out of control. Encounters

with severe turbulence must be remedied immediately in any phase of flight. Severe turbulence may be

associated with MWA.

3. Mountain Wave Activity (MWA)

(a) Significant MWA occurs both below and above the floor of RVSM airspace, FL 290. MWA often

occurs in western states in the vicinity of mountain ranges. It may occur when strong winds blow perpendicular

to mountain ranges resulting in up and down or wave motions in the atmosphere. Wave action can produce

altitude excursions and airspeed fluctuations accompanied by only light turbulence. With sufficient amplitude,

however, wave action can induce altitude and airspeed fluctuations accompanied by severe turbulence. MWA

is difficult to forecast and can be highly localized and short lived.

(b) Wave activity is not necessarily limited to the vicinity of mountain ranges. Pilots experiencing wave

activity anywhere that significantly affects altitude−keeping can follow the guidance provided below.

4−6−4 Operational Policy/Procedures for Reduced Vertical Separation Minimum (RVSM) in the

Domestic U.S., Alaska, Offshore Airspace and the San Juan FIR

2/20/25 AIM

(c) Inflight MWA Indicators (Including Turbulence). Indicators that the aircraft is being subjected to

MWA are:

(1) Altitude excursions and/or airspeed fluctuations with or without associated turbulence.

(2) Pitch and trim changes required to maintain altitude with accompanying airspeed fluctuations.

(3) Light to severe turbulence depending on the magnitude of the MWA.

4. Priority for Controller Application of Merging Target Procedures

(a) Explanation of Merging Target Procedures. As described in subparagraph c3 below, A TC will use

“merging target procedures” to mitigate the effects of both severe turbulence and MWA. The procedures in

subparagraph c3 have been adapted from existing procedures published in FAA Order JO 7110.65, Air Traffic

Control, paragraph 5−1−4, Merging Target Procedures. Paragraph 5−1−4 calls for en route controllers to advise

pilots of potential traffic that they perceive may fly directly above or below his/her aircraft at minimum vertical

separation. In response, pilots are given the option of requesting a radar vector to ensure their radar target will

not merge or overlap with the traffic’s radar target.

(b) The provision of “merging target procedures” to mitigate the effects of severe turbulence and/or

MWA is not optional for the controller, but rather is a priority responsibility. Pilot requests for vectors for traffic

avoidance when encountering MWA or pilot reports of “Unable RVSM due turbulence or MWA” are considered

first priority aircraft separation and sequencing responsibilities. (FAA Order JO 7110.65, paragraph 2−1−2, Duty

Priority, states that the controller’s first priority is to separate aircraft and issue safety alerts).

(c) Explanation of the term “traffic permitting.” The contingency actions for MWA and severe

turbulence detailed in paragraph 4−6−9, Contingency Actions: Weather Encounters and Aircraft System Failures

that Occur After Entry into RVSM Airspace, state that the controller will “vector aircraft to avoid merging targets

with traffic at adjacent flight levels, traffic permitting.” The term “traffic permitting” is not intended to imply

that merging target procedures are not a priority duty. The term is intended to recognize that, as stated in FAA

Order JO 7110.65, paragraph 2−1−2, Duty Priority, there are circumstances when the controller is required to

perform more than one action and must “exercise their best judgment based on the facts and circumstances known

to them” to prioritize their actions. Further direction given is: “That action which is most critical from a safety

standpoint is performed first.”

5. TCAS Sensitivity. For both MWA and severe turbulence encounters in RVSM airspace, an additional

concern is the sensitivity of collision avoidance systems when one or both aircraft operating in close proximity

receive TCAS advisories in response to disruptions in altitude hold capability.

b. Pre−flight tools. Sources of observed and forecast information that can help the pilot ascertain the

possibility of MW A or severe turbulence are: Forecast Winds and Temperatures Aloft (FD), Area Forecast (FA),

Graphical Turbulence Guidance (GTG), SIGMETs and PIREPs.

c. Pilot Actions When Encountering Weather (e.g., Severe Turbulence or MWA)

1. Weather Encounters Inducing Altitude Deviations of Approximately 200 feet. When the pilot

experiences weather induced altitude deviations of approximately 200 feet, the pilot will contact ATC and state

“Unable RVSM Due (state reason)” (e.g., turbulence, mountain wave). See contingency actions in paragraph

4−6−9.

2. Severe Turbulence (including that associated with MWA). When pilots encounter severe turbulence,

they should contact ATC and report the situation. Until the pilot reports clear of severe turbulence, the controller

will apply merging target vectors to one or both passing aircraft to prevent their targets from merging:

EXAMPLE−

“Yankee 123, FL 310, unable RVSM due severe turbulence.”

“Yankee 123, fly heading 290; traffic twelve o’clock, 10 miles, opposite direction; eastbound MD−80 at FL 320” (or the

controller may issue a vector to the MD−80 traffic to avoid Yankee 123).

Operational Policy/Procedures for Reduced Vertical Separation Minimum (RVSM) in the 4−6−5

Domestic U.S., Alaska, Offshore Airspace and the San Juan FIR

AIM 2/20/25

3. MWA. When pilots encounter MWA, they should contact ATC and report the magnitude and location

of the wave activity. When a controller makes a merging targets traffic call, the pilot may request a vector to avoid

flying directly over or under the traffic. In situations where the pilot is experiencing altitude deviations of 200

feet or greater, the pilot will request a vector to avoid traffic. Until the pilot reports clear of MWA, the controller

will apply merging target vectors to one or both passing aircraft to prevent their targets from merging:

EXAMPLE−

“Yankee 123, FL 310, unable RVSM due mountain wave.”

“Yankee 123, fly heading 290; traffic twelve o’clock, 10 miles, opposite direction; eastbound MD−80 at FL 320” (or the

controller may issue a vector to the MD−80 traffic to avoid Yankee 123).

4. FL Change or Re−route. To leave airspace where MWA or severe turbulence is being encountered, the

pilot may request a FL change and/or re−route, if necessary.

4−6−7. Guidance on Wake Turbulence

a. Pilots should be aware of the potential for wake turbulence encounters in RVSM airspace. Experience

gained since 1997 has shown that such encounters in RVSM airspace are generally moderate or less in magnitude.

b. Prior to DRVSM implementation, the FAA established provisions for pilots to report wake turbulence

events in RVSM airspace using the NASA Aviation Safety Reporting System (ASRS). A “Safety Reporting”

section established on the FAA RVSM Documentation web page provides contacts, forms, and reporting

procedures.

c. To date, wake turbulence has not been reported as a significant factor in DRVSM operations. European

authorities also found that reports of wake turbulence encounters did not increase significantly after RVSM

implementation (eight versus seven reports in a ten−month period). In addition, they found that reported wake

turbulence was generally similar to moderate clear air turbulence.

d. Pilot Action to Mitigate Wake Turbulence Encounters

1. Pilots should be alert for wake turbulence when operating:

(a) In the vicinity of aircraft climbing or descending through their altitude.

(b) Approximately 10−30 miles after passing 1,000 feet below opposite−direction traffic.

(c) Approximately 10−30 miles behind and 1,000 feet below same−direction traffic.

2. Pilots encountering or anticipating wake turbulence in DRVSM airspace have the option of requesting

a vector, FL change, or if capable, a lateral offset.

NOTE−

1. Offsets of approximately a wing span upwind generally can move the aircraft out of the immediate vicinity of another

aircraft’ s wake vortex.

2. In domestic U.S. airspace, pilots must request clearance to fly a lateral offset. Strategic lateral offsets flown in oceanic

airspace do not apply.

4−6−8. Pilot/Controller Phraseology

TBL 4−6−1 shows standard phraseology that pilots and controllers will use to communicate in DRVSM

operations.

4−6−6 Operational Policy/Procedures for Reduced Vertical Separation Minimum (RVSM) in the

Domestic U.S., Alaska, Offshore Airspace and the San Juan FIR

2/20/25 AIM

TBL 4−6−1

Pilot/Controller Phraseology

Message Phraseology

For a controller to ascertain the RVSM approval status of

an aircraft:

(call sign) confirm RVSM approved

Pilot indication that flight is RVSM approved Affirm RVSM

Pilot report of lack of RVSM approval (non−RVSM status).

Pilot will report non−RVSM status, as follows:

a. On the initial call on any frequency in the RVSM

airspace and . . ..

b. In all requests for flight level changes pertaining to

flight levels within the RVSM airspace and . . ..

c. In all read backs to flight level clearances pertaining

to flight levels within the RVSM airspace and . . ..

d. In read back of flight level clearances involving

climb and descent through RVSM airspace

(FL 290 − 410).

Negative RVSM, (supplementary information,

e.g., “Certification flight”).

Pilot report of one of the following after entry into RVSM

airspace: all primary altimeters, automatic altitude control

systems or altitude alerters have failed.

(See paragraph 4−6−9, Contingency Actions: Weather

Encounters and Aircraft System Failures that Occur After

Entry into RVSM Airspace.)

NOTE−

This phrase is to be used to convey both the initial indication of

RVSM aircraft system failure and on initial contact on all

frequencies in RVSM airspace until the problem ceases to exist

or the aircraft has exited RVSM airspace.

Unable RVSM Due Equipment

ATC denial of clearance into RVSM airspace Unable issue clearance into RVSM airspace, maintain FL

*Pilot reporting inability to maintain cleared flight level

due to weather encounter.

(See paragraph 4−6−9, Contingency Actions: Weather

Encounters and Aircraft System Failures that Occur After

Entry into RVSM Airspace.).

*Unable RVSM due (state reason) (e.g., turbulence,

mountain wave)

ATC requesting pilot to confirm that an aircraft has

regained RVSM−approved status or a pilot is ready to

resume RVSM

Confirm able to resume RVSM

Pilot ready to resume RVSM after aircraft system or

weather contingency

Ready to resume RVSM

4−6−9. Contingency Actions: Weather Encounters and Aircraft System Failures that Occur

After Entry into RVSM Airspace

TBL 4−6−2 provides pilot guidance on actions to take under certain conditions of aircraft system failure that

occur after entry into RVSM airspace and weather encounters. It also describes the expected ATC controller

actions in these situations. It is recognized that the pilot and controller will use judgment to determine the action

most appropriate to any given situation.

Operational Policy/Procedures for Reduced Vertical Separation Minimum (RVSM) in the 4−6−7

Domestic U.S., Alaska, Offshore Airspace and the San Juan FIR

AIM 2/20/25

TBL 4−6−2

Contingency Actions: Weather Encounters and Aircraft System Failures that Occur After Entry into RVSM

Airspace

Initial Pilot Actions in Contingency Situations

Initial pilot actions when unable to maintain flight level (FL) or unsure of aircraft altitude−keeping

capability:

Notify ATC and request assistance as detailed below.

Maintain cleared flight level, to the extent possible, while evaluating the situation.

Watch for conflicting traffic both visually and by reference to TCAS, if equipped.

Alert nearby aircraft by illuminating exterior lights (commensurate with aircraft limitations).

Severe Turbulence and/or Mountain Wave Activity (MWA) Induced

Altitude Deviations of Approximately 200 feet

Pilot will: Controller will:

When experiencing severe turbulence and/or Vector aircraft to avoid merging target with

MW A induced altitude deviations of traffic at adjacent flight levels, traffic permitting

approximately 200 feet or greater, pilot will

contact ATC and state “Unable RVSM Due (state Advise pilot of conflicting traffic

reason)” (e.g., turbulence, mountain wave)

Issue FL change or re−route, traffic permitting

If not issued by the controller, request vector

clear of traffic at adjacent FLs Issue PIREP to other aircraft

If desired, request FL change or re−route

Report location and magnitude of turbulence or

MW A to ATC

See paragraph 4−6−6, Guidance on Severe Paragraph 4−6−6 explains “traffic permitting.”

Turbulence and Mountain Wave Activity (MWA) for

detailed guidance.

Mountain Wave Activity (MWA) Encounters − General

Pilot actions:

Contact ATC and report experiencing MWA

If so desired, pilot may request a FL change or

re−route

Report location and magnitude of MWA to ATC

See paragraph 4−6−6 for guidance on MWA.

Controller actions:

Advise pilot of conflicting traffic at adjacent FL

If pilot requests, vector aircraft to avoid merging

target with traffic at adjacent RVSM flight levels,

traffic permitting

Issue FL change or re−route, traffic permitting

Issue PIREP to other aircraft

Paragraph 4−6−6 explains “traffic permitting.”

NOTE−

MWA encounters do not necessarily result in altitude deviations on the order of 200 feet. The guidance below is

intended to address less significant MWA encounters.

Operational Policy/Procedures for Reduced Vertical Separation Minimum (RVSM) in the

Domestic U.S., Alaska, Offshore Airspace and the San Juan FIR

4−6−8

2/20/25 AIM

Wake Turbulence Encounters

Pilot should:

Contact ATC and request vector, FL change or,

if capable, a lateral offset

See paragraph 4−6−7, Guidance on Wake

Turbulence.

Controller should:

Issue vector, FL change or lateral offset

clearance, traffic permitting

Paragraph 4−6−6 explains “traffic permitting.”

“Unable RVSM Due Equipment”

Failure of Automatic Altitude Control System, Altitude Alerter or All Primary Altimeters

Pilot will:

Contact ATC and state “Unable RVSM Due

Equipment”

Request clearance out of RVSM airspace unless

operational situation dictates otherwise

Controller will:

Provide 2,000 feet vertical separation or

appropriate horizontal separation

Clear aircraft out of RVSM airspace unless

operational situation dictates otherwise

One Primary Altimeter Remains Operational

Pilot will:

Cross check stand−by altimeter

Notify ATC of operation with single primary

altimeter

If unable to confirm primary altimeter accuracy,

follow actions for failure of all primary altimeters

Controller will:

Acknowledge operation with single primary

altimeter

Transponder Failure

Pilot will:

Contact ATC and request authority to continue

to operate at cleared flight level

Comply with revised ATC clearance, if issued

NOTE−

14 CFR section 91.215 (ATC transponder and altitude

reporting equipment and use) regulates operation with the

transponder inoperative.

Controller will:

Consider request to continue to operate at

cleared flight level

Issue revised clearance, if necessary

4−6−10. Procedures for Accommodation of Non −RVSM Aircraft

a. General Policies for Accommodation of Non−RVSM Aircraft

1. The RVSM mandate calls for only RVSM authorized aircraft/operators to fly in designated RVSM

airspace with limited exceptions. The policies detailed below are intended exclusively for use by aircraft that the

FAA has agreed to accommodate. They are not intended to provide other operators a means to circumvent the

normal RVSM approval process.

2. If the operator is not authorized or the aircraft is not RVSM−compliant, the aircraft will be referred to

as a “non−RVSM” aircraft. 14 CFR section 91.180 and part 91, Appendix G, enable the FAA to authorize a

deviation to operate a non−RVSM aircraft in RVSM airspace.

Operational Policy/Procedures for Reduced Vertical Separation Minimum (RVSM) in the 4−6−9

Domestic U.S., Alaska, Offshore Airspace and the San Juan FIR

AIM 2/20/25

3. Non−RVSM aircraft flights will be handled on a workload permitting basis. The vertical separation

standard applied between aircraft not approved for RVSM and all other aircraft must be 2,000 feet.

4. Required Pilot Calls. The pilot of non−RVSM aircraft will inform the controller of the lack of RVSM

approval in accordance with the direction provided in paragraph 4−6−8, Pilot/Controller Phraseology.

b. Categories of Non−RVSM Aircraft that may be Accommodated

Subject to FAA approval and clearance, the following categories of non−RVSM aircraft may operate in domestic

U.S. RVSM airspace provided they have an operational transponder.

1. Department of Defense (DoD) aircraft.

2. Flights conducted for aircraft certification and development purposes.

3. Active air ambulance flights utilizing a “MEDEV AC” call sign.

4. Aircraft climbing/descending through RVSM flight levels (without intermediate level off) to/from FLs

above RVSM airspace (Policies for these flights are detailed in paragraph 4−6−11, Non−RVSM Aircraft

Requesting Climb to and Descent from Flight Levels Above RVSM Airspace Without Intermediate Level Off.

5. Foreign State (government) aircraft.

c. Methods for operators of non−RVSM aircraft to request access to RVSM Airspace. Operators may:

1. LOA/MOU. Enter into a Letter of Agreement (LOA)/Memorandum of Understanding (MOU) with the

RVSM facility (the Air Traffic facility that provides air traffic services in RVSM airspace). Operators must

comply with LOA/MOU.

2. File−and−Fly. File a flight plan to notify the FAA of their intention to request access to RVSM airspace.

NOTE−

Priority for access to RVSM airspace will be afforded to RVSM compliant aircraft, then File−and−Fly flights.

4−6−11. Non−RVSM Aircraft Requesting Climb to and Descent from Flight Levels Above

RVSM Airspace Without Intermediate Level Off

a. File−and−Fly. Operators of Non−RVSM aircraft climbing to and descending from RVSM flight levels

should just file a flight plan.

b. Non−RVSM aircraft climbing to and descending from flight levels above RVSM airspace will be handled

on a workload permitting basis. The vertical separation standard applied in RVSM airspace between non−RVSM

aircraft and all other aircraft must be 2,000 feet.

c. Non−RVSM aircraft climbing to/descending from RVSM airspace can only be considered for

accommodation provided:

1. Aircraft is capable of a continuous climb/descent and does not need to level off at an intermediate altitude

for any operational considerations and

2. Aircraft is capable of climb/descent at the normal rate for the aircraft.

d. Required Pilot Calls. The pilot of non−RVSM aircraft will inform the controller of the lack of RVSM

approval in accordance with the direction provided in paragraph 4−6−8, Pilot/Controller Phraseology.

4−6−10 Operational Policy/Procedures for Reduced Vertical Separation Minimum (RVSM) in the

Domestic U.S., Alaska, Offshore Airspace and the San Juan FIR

AIM2/20/258/7/25 AIM1/22/26 AIM

Section 7. Operational Policy/Procedures for the Gulf of

America 50 NM Lateral Separation Initiative

4−7−1. Introduction and General Policies

a. Air traffic control (ATC) may apply 50 nautical mile (NM) lateral separation (i.e., lateral spacing) between

airplanes authorized for Required Navigation Performance (RNP) 10 or RNP 4 operating in the Gulf of America.

50 NM lateral separation may be applied in the following airspace:

1. Houston Oceanic Control Area (CTA)/Flight Information Region (FIR).

2. Gulf of America portion of the Miami Oceanic CTA/FIR.

3. Monterrey CTA.

4. Merida High CTA within the Mexico CTA/FIR.

b. Within the Gulf of America airspace described above, pairs of airplanes whose flight plans indicate

approval for PBN and either RNP 10 or RNP 4 may be spaced by A TC at lateral intervals of 50 NM. ATC will

space any airplane without RNP 10 or RNP 4 capability such that at least 90 NM lateral separation is maintained

with other airplanes in the Miami Oceanic CTA/FIR, and at least 100 NM separation is maintained in the

Houston, Monterrey, and Merida CTA/FIRs.

c. The reduced lateral separation allows more airplanes to fly on optimum routes/altitudes over the Gulf of

America.

d. 50 NM lateral separation is not applied on routes defined by ground navigation aids or on Gulf RNA V

Routes Q100, Q102, or Q105.

e. Useful information for flight planning and operations over the Gulf of America, under this 50 NM lateral

separation policy, as well as information on how to obtain RNP 10 or RNP 4 authorization, can be found in the

West Atlantic, Gulf of America, and Caribbean Resource Guide for U.S. Operators located at:

https://www.faa.gov/headquartersoffices/avs/wat−gulf−and−caribbean−resource−guide.

4−7−2. Accommodating Non−RNP 10 Aircraft

a. Operators not authorized for RNP 10 or RNP 4 may still file for any route and altitude within the Gulf of

America CTAs. However, clearance on the operator’s preferred route and/or altitude will be provided as traffic

allows for 90 or 100 NM lateral separation between the non −RNP 10 aircraft and any others. Priority will be

given to RNP 10 or RNP 4 aircraft.

b. Operators of aircraft not authorized RNP 10 or RNP 4 must include the annotation “RMK/NONRNP10”

in Item 18 of their ATC flight plan.

c. Pilots of non−RNP 10 aircraft are to remind ATC of their RNP status; i.e., report “negative RNP 10” upon

initial contact with ATC in each Gulf CTA/FIR.

d. Operators will likely benefit from the effort they invest to obtain RNP 10 or RNP 4 authorization, provided

they are flying aircraft equipped to meet RNP 10 or RNP 4 standards.

4−7−3. Obtaining RNP 10 or RNP 4 Operational Authorization

a. For U.S. operators, AC 90−105, Approval Guidance for RNP Operations and Barometric Vertical

Navigation in the U.S. National Airspace System and in Oceanic and Remote Continental Airspace, provides

the aircraft and operator qualification criteria for RNP 10 or RNP 4 authorizations. FAA personnel at flight

standards district offices (FSDO) and certificate management offices (CMO) will use the guidance contained

Operational Policy/Procedures for the Gulf of America 50 NM Lateral Separation Initiative 4−7−1

AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26

in AC 90−105 to evaluate an operator’s application for RNP 10 or RNP 4 authorization. Authorization to conduct

RNP operations in oceanic airspace is provided to all U.S. operator s through issuance of Operations

Specification (OpSpec), Management Specification (MSpec), or Letter of Authorization (LOA) B036, as

applicable to the nature of the operation; for example, part 121, part 91, etc. Operators may wish to review FAA

Order 8900.1, Flight Standards Information Management System, volume 3, chapter 18, section 4, to understand

the specific criteria for issuing OpSpec, MSpec, and/or LOA B036.

b. The operator’s RNP 10 or RNP 4 authorization should include any equipment requirements and RNP 10

time limits (if operating solely inertial−based navigation systems), which must be observed when conducting

RNP operations. RNP 4 requires tighter navigation and track maintenance accuracy than RNP 10.

4−7−4. Authority for Operations with a Single Long −Range Navigation System

Operators may be authorized to take advantage of 50 NM lateral separation in the Gulf of America CTAs when

equipped with only a single long−range navigation system. RNP 10 with a single long−range navigation system

is authorized via OpSpec, MSpec, or LOA B036, Table 2. Operators should contact their FSDO or CMO to

obtain information on the specific requirements for obtaining B036. V olume 3, chapter 18, section 4 of FAA

Order 8900.1 provides the qualification criteria to be used by FAA aviation safety inspectors in issuing B036.

4−7−5. Flight Plan Requirements

a. In order for an operator with RNP 10 or RNP 4 authorization to obtain 50 NM lateral separation in the Gulf

of America CTAs/FIRs, and therefore obtain preferred routing available to RNP authorized aircraft, the

international flight plan form (FAA 7233−4) must be annotated as follows:

1. Item 10a (Equipment) must include the letter “R.”

2. Item 18 must include either “PBN/A1” for RNP 10 authorization or “PBN/L1” for RNP 4 authorization.

b. Indication of RNP 4 authorization implies the aircraft and pilots are also authorized RNP 10.

c. Chapter 5, Section 1, of this manual includes information on all flight plan codes. RNP 10 has the same

meaning and application as RNA V 10. They share the same code.

4−7−6. Contingency Procedures

Pilots operating under reduced lateral separation must be particularly familiar with, and prepared to rapidly

implement, the standard contingency procedures specifically written for operations when outside ATC

surveillance and direct VHF communications (for example, the oceanic environment). Specific procedures have

been developed for weather deviations. Operators should ensure all flight crews operating in this type of

environment have been provided the standard contingency procedures in a readily accessible format. The margin

for error when operating at reduced separation mandates correct and expeditious application of the standard

contingency procedures. These internationally accepted procedures are published in ICAO Document 4444,

chapter 15. The procedures are also reprinted in the U.S. Aeronautical Information Publication (AIP), En Route

(ENR) Section 7.3, Special Procedures for In−flight Contingencies in Oceanic Airspace; and AC 91−70.

4−7−2 Operational Policy/Procedures for the Gulf of America 50 NM Lateral Separation Initiative

AIM2/20/251/22/26 AIM

Chapter 5. Air Traffic Procedures

Section 1. Preflight

5−1−1. Preflight Preparation

a. Prior to every flight, pilots should gather all information vital to the nature of the flight, assess whether the

flight would be safe, and then file a flight plan. Pilots can receive a regulatory compliant briefing without

contacting Flight Service. Pilots are encouraged to use automated resources and review Advisory Circular AC

91−92, Pilot’s Guide to a Preflight Briefing, for more information. Pilots who prefer to contact Flight Service

are encouraged to conduct a self−brief prior to calling. Conducting a self−brief before contacting Flight Service

provides familiarity of meteorological and aeronautical conditions applicable to the route of flight and promotes

a better understanding of weather information. Pilots may access Flight Service through www.1800wxbrief.com

or by calling 1− 800−WX−BRIEF (1 −800−992−7433) in the CONUS, Hawaii, and U.S. territories; or

1–833–AK–BRIEF (1−833−252−7433) in Alaska. Flight planning applications are also available for conducting

a self−briefing and filing flight plans.

NOTE−

Alaska only: Pilots filing flight plans via “fast file” who desire to have their briefing recorded, should include a statement

at the end of the recording as to the source of their weather briefing.

b. The information required by the FAA to process flight plans is obtained from FAA Form 7233 −4,

International Flight Plan. Only DoD users, and civilians who file stereo route flight plans, may use FAA Form

7233−1, Flight Plan.

NOTE−

FAA and DoD Flight Plan Forms are equivalent. Where the F AA specifies Form 7233−1, Flight Plan and F AA Form 7233−4,

International Flight Plan, the DoD may substitute their Form DD 175, Military Flight Plan and Form DD −1801, DoD

International Flight Plan as necessary. NAS automation systems process and convert data in the same manner, although for

computer acceptance, input fields may be adjusted to follow F AA format.

c. FSSs are required to advise of pertinent NOTAMs if a standard briefing is requested, but if they are

overlooked, do not hesitate to remind the specialist that you have not received NOTAM information.

Additionally, FSS briefers do not provide FDC NOTAM information for special instrument approach procedures

unless specifically asked. Pilots authorized by the FAA to use special instrument approach procedures must

specifically request FDC NOTAM information for thes e procedures. Pilots who receive the information

electronically will receive NOTAMs for special IAPs automatically.

NOTE−

Domestic Notices and International Notices are not provided during a briefing unless specifically requested by the pilot since

the FSS specialist has no way of knowing whether the pilot has already checked the Federal NOTAM System (FNS) NOTAM

Search website external links prior to calling. Airway NOTAMs, procedural NOTAMs, and NOTAMs that are general in

nature and not tied to a specific airport/facility (for example, flight advisories and restrictions, open duration special

security instructions, and special flight rules areas) are briefed solely by pilot request. Remember to ask for these notices

if you have not already reviewed this information, and to request all pertinent NOTAMs specific to your flight.

REFERENCE−

AIM, Para 5−1−3, Notice to Airmen (NOTAM) System.

d. Pilots are urged to use only the latest issue of aeronautical charts in planning and conducting flight

operations. Aeronautical charts are revised and reissued on a regular scheduled basis to ensure that depicted data

are current and reliable. In the conterminous U.S., Sectional Charts are updated every 56 days, IFR En Route

Charts every 56 days, and amendments to civil IFR Approach Charts are accomplished on a 56−day cycle with

a change notice volume issued on the 28−day midcycle. Charts that have been superseded by those of a more

recent date may contain obsolete or incomplete flight information.

Preflight 5−1−1

AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26

REFERENCE−

AIM. Para 5–4–5, Instrument Approach Procedure (IAP) Charts.

AIM, Para 9–1–5, General Description of Each Chart Series.

e. When requesting a preflight briefing, identify yourself as a pilot and provide the following:

1. Type of flight planned; e.g., VFR or IFR.

2. Aircraft’s number or pilot’s name.

3. Aircraft type.

4. Departure Airport.

5. Route of flight.

6. Destination.

7. Flight altitude(s).

8. ETD and ETE.

f. Prior to conducting a briefing, briefers are required to have the background information listed above so that

they may tailor the briefing to the needs of the proposed flight. The objective is to communicate a “picture” of

meteorological and aeronautical information necessary for the conduct of a safe and efficient flight. Briefers use

all available weather and aeronautical information to summarize data applicable to the proposed flight. Pilots

who have briefed themselves before calling Flight Service should advise the briefer what information has been

obtained from other sources.

REFERENCE−

AIM, Para 7−1−5, Preflight Briefings, contains those items of a weather briefing that should be expected or requested.

g. FAA by 14 CFR part 93, Subpart K, has designated High Density Traffic Airports (HDTA) and has

prescribed air traffic rules and requirements for operating aircraft (excluding helicopter operations) to and from

these airports.

REFERENCE−

Chart Supplement, Special Notices Section.

AIM, Para 4−1−21, Airport Reservation Operations and Special Traffic Management Programs.

h. In addition to the filing of a flight plan, if the flight will traverse or land in one or more foreign countries,

it is particularly important that pilots leave a complete itinerary with someone directly concerned and keep that

person advised of the flight’s progress. If serious doubt arises as to the safety of the flight, that person should

first contact the FSS.

REFERENCE−

AIM, Para 5−1−1 1, Flights Outside the U.S. and U.S. Territories.

i. Pilots operating under provisions of 14 CFR part 135 on a domestic flight without having an FAA assigned

3−letter designator, must prefix the normal registration (N) number with the letter “T” on flight plan filing; for

example, TN1234B.

REFERENCE−

AIM, Para 4−2−4, Aircraft Call Signs.

F AA Order JO 7110.65, Para 2−3−5, Aircraft Identity, Subpara a.

F AA Order JO 7110.10, Appendix B, FAA Form 7233−1, Flight Plan

5−1−2. Follow IFR Procedures Even When Operating VFR

a. To maintain IFR proficiency, pilots are urged to practice IFR procedures whenever possible, even when

operating VFR. Some suggested practices include:

1. Obtain a complete preflight briefing and check NOTAMs. Prior to every flight, pilots should gather all

information vital to the nature of the flight. Pilots can receive a regulatory compliant briefing without contacting

Flight Service. Pilots are encouraged to use automated resources and review AC 91 −92, Pilot’s Guide to a

Preflight Briefing, for more information. NOTAMs are available online from the Federal NOTAM System (FNS)

5−1−2 Preflight

AIM2/20/257/9/26 AIM

NOTAM search website (https://notams.aim.faa.gov/notamSearch/), private vendors, or on request from Flight

Service.

2. File a flight plan. This is an excellent low−cost insurance policy. The cost is the time it takes to fill it out.

The insurance includes the knowledge that someone will be looking for you if you become overdue at your

destination. Pilots can file flight plans either by using a website or by calling Flight Service. Flight planning

applications are also available to file, activate, and close VFR flight plans.

3. Use current charts.

4. To enhance situational awareness and minimize distractions during critical phases of flight, pre−load all

intended waypoints into a suitable RNA V system while the aircraft is on the ground.

5. Use the navigation aids . Practice maintaining a good course; keep the course deviation indicator

centered.

6. Maintain a constant altitude that is appropriate for the direction of flight.

7. Estimate en route position times.

8. Make accurate and frequent position reports to the FSSs along your route of flight.

b. Simulated IFR flight is recommended (under the hood); however, pilots are cautioned to review and adhere

to the requirements specified in 14 CFR section 91.109 before and during such flight.

c. When flying VFR at night, in addition to the altitude appropriate for the direction of flight, pilots should

maintain an altitude which is at or above the minimum en route altitude as shown on charts. This is especially

true in mountainous terrain, where there is usually very little ground reference. Do not depend on your eyes alone

to avoid rising unlighted terrain, or even lighted obstructions such as TV towers.

5−1−3. Notice to Airmen (NOTAM) System

a. General. The NOTAM system provides pilots with time critical aeronautical information that is temporary,

or information to be published on aeronautical charts at a later date, or information from another operational

publication. The NOTAM is cancelled when the information in the NOTAM is published on the chart or

when the temporary condition is returned to normal status. NOTAMs may be disseminated up to 7 days before

the start of activity. Pilots can access NOTAM information online via NOTAM Search at :

https://notams.aim.faa.gov/notamSearch/ or from an FSS.

b. Preflight. 14 CFR § 91.103, Preflight Action directs p ilots to become familiar with all available

information concerning a planned flight prior to departure, including NOTAMs. Pilots may change their flight

plan based on available information. Current NOTAM information may affect:

1. Aerodromes.

2. Runways, taxiways, and ramp restrictions.

3. Obstructions.

4. Communications.

5. Airspace.

6. Status of navigational aids or radar service availability.

7. Other information essential to planned en route, terminal, or landing operations.

c. ARTCC NOTAMs. Pilots should also review NOTAMs for the ARTCC area (for example, Washington

Center (ZDC), Cleveland Center (ZOB), etc.) in which the flight will be operating. You can find the 3 letter code

for each ARTCC on the FAA’s NOTAM webpage. These NOTAMs may affect the planned flight. Some of the

operations include Central Altitude Reservation Function (CARF), Special Use Airspace (SUA), Temporary

Preflight 5−1−3

AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26

Flight Restrictions (TFR), Global Positioning System (GPS), Flight Data Center (FDC) changes to routes, wind

turbine, and Unmanned Aircraft System (UAS).

NOTE−

NOTAM information is transmitted using ICAO contractions to reduce transmission time. See TBL 5−1−2 for a listing of the

most commonly used contractions, or go online to the following URL:

https://www.notams.faa.gov/downloads/contractions.pdf. For a complete listing of approved NOTAM Contractions, see

F AA Order JO 7340.2, Contractions.

d. Destination Update. Pilots should also contact ATC or FSS while en route to obtain updated airfield

information for their destination. This is particularly important when flying to the airports without an operating

control tower. Snow removal, fire and rescue activities, construction, and wildlife encroachment, may pose

hazards to pilots. This information may not be available to pilots prior to arrival/departure.

e. NA V AID NOTAMs. Pilots should check NOTAMs to ensure NA V AIDs required for the flight are in

service. A NOTAM is published when a NA VAID is out of service or Unserviceable (U/S). Although a NA VAID

is deemed U/S and planned for removal from service, it may be a long time before that NA V AID is officially

decommissioned and removed from charts. A NOTAM is the primary method of alerting pilots to its

unavailability. Pilots using VFR charts can also review the Aeronautical Information Services’ (AIS) website

concerning Safety Alerts, Charting Notices, and Digital Product Notices at

https://www.faa.gov/air_traffic/flight_info/aeronav/safety_alerts/ for additional chart information.

f. GPS NOTAMs. The FAA issues information on the status of GPS through the NOTAM system. Operators

may find information on GPS satellite outages, GPS testing, and GPS anomalies by specifically searching for

GPS NOTAMS prior to flight.

1. The NOTAM system uses the terms UNRELIABLE (UNREL), MAY NOT BE A V AILABLE (A VBL),

and NOT A V AILABLE (A VBL) when describing the status of GPS. UNREL indicates the expected level of

service of the GPS and/or WAAS may not be available. Pilots must then determine the adequacy of the signal

for desired use. Aircraft should have additional navigation equipment for their intended route.

NOTE−

Unless associated with a known testing NOTAM, pilots should report GPS anomalies, including degraded operation and/or

loss of service, as soon as possible via radio or telephone, and via the GPS Anomaly Reporting Form. (See 1−1−13.)

2. GPS operations may also be NOTAMed for testing. This is indicated in the NOTAM language with the

name of the test in parenthesis. When GPS testing NOTAMS are published and testing is actually occurring, ATC

will advise pilots requesting or cleared for a GPS or RNA V (GPS) approach, that GPS may not be available and

request the pilot’s intentions. TBL 5−1−1 lists an example of a GPS testing NOTAM.

g. NOTAM Classification. NOTAM information is classified as Domestic NOTAMs (NOTAM D), Flight

Data Center (FDC) NOTAMs, International NOTAMs, or Military NOTAMs.

1. NOTAM (D) information is disseminated for all navigational facilities that are part of the National

Airspace System (NAS), all public use aerodromes, seaplane bases, and heliports listed in the Chart Supplement.

NOTAM (D) information includes taxiway closures, personnel and equipment near or crossing runways, and

airport lighting aids that do not affect instrument approach criteria (i.e., VGSI). All NOTAM Ds must have one

of the keywords listed in TBL 5−1−1, as the first part of the text after the location identifier. These keywords

categorize NOTAM Ds by subject, for example, APRON (ramp), RWY (runway), SVC (Services), etc. There

are several types of NOTAM Ds:

(a) Aerodrome activity and conditions, to include field conditions.

(b) Airspace to include CARF, SUA, and general airspace activity like UAS or pyrotechnics.

(c) Visual and radio navigational aids.

(d) Communication and services.

(e) Pointer NOTAMs. NOTAMs issued to point to additional aeronautical information. When pointing

to another NOTAM, the keyword in the pointer NOTAM must match the keyword in the original NOTAM.

5−1−4 Preflight

AIM2/20/257/9/26 AIM

Pointer NOTAMs should be issued for, but are not limited to, TFRs, Airshows, Temporary SUA, major NAS

system interruptions, etc.

2. FDC NOTAMs are issued when it is necessary to disseminate regulatory information. FDC NOTAMs

include:

(a) Amendments to published IAPs and other current aeronautical charts.

(b) Temporary Flight Restrictions (TFR) restrict entrance to a certain airspace at a certain time, however,

some TFRs provide relief if ATC permission is given to enter the area when requested. Online preflight resources

for TFRs provide graphics and plain language interpretations.

(c) High barometric pressure warning.

(d) Laser light activity.

(e) ADS−B, TIS−B, and FIS−B service availability.

(f) Satellite−based systems such as WAAS or GPS.

(g) Special Notices.

3. International NOTAMs are published in ICAO format per Annex 15 and distributed to multiple countries.

(a) International NOTAMs issued by the U.S. NOTAM Office use Series A followed by 4 sequential

numbers, a slant “/” and a 2−digit number representing the year the NOTAM was issued. International NOTAMs

basically duplicate data found in a U.S. Domestic NOTAM.

(b) Not every topic of a U.S. Domestic NOTAM is issued as an International NOTAM by the U.S. The

U.S. International NOTAM will be linked to the appropriate U.S. Domestic NOTAM when possible.

(c) International NOTAMs received by the FAA from other countries are stored in the U.S. NOTAM

System.

(d) The International NOTAM format includes a “Q” Line that can be easily read/parsed by a computer

and allows the NOTAM to be displayed digitally.

(1) Field A: ICAO location identifier or FIR affected by the NOTAM.

(2) Field B: Start of Validity.

(3) Field C: End of Validity (both in [Year][Month][Day][Hour][Minute] format).

(4) Field D: (when present) Schedule.

(5) Field E: Full NOTAM description.

(6) Field F: (when present) Lowest altitude, or “SFC.”

(7) Field G: (when present) Highest altitude, or “UNL.”

(e) For more on International format, please see Annex 15.

4. Military NOTAMs are NOTAMs originated by the U.S. Air Force, Army, Marine, or Navy, and

pertaining to military or joint−use navigational aids/airports that are part of the NAS. Military NOTAMs are

published in the International NOTAM format and should be reviewed by users of a military or joint−use facility.

h. Security NOTAMS:

1. U.S. Domestic Security NOTAMS are FDC NOTAMS that inform pilots of certain U.S. security

activities or requirements, such as Special Security Instructions for aircraft operations to, from, within, or

transitioning U.S. territorial airspace. These NOTAMS are found on the Federal NOTAM System (FNS)

NOTAM Search website under the location designator KZZZ.

2. United States International Flight Prohibitions, Potential Hostile Situations, and Foreign Notices are

issued by the FAA and are found on the Federal NOTAM System (FNS) NOTAM Search website under the

location designator KICZ.

Preflight 5−1−5

AIM 2/20/25

TBL 5−1−1

NOTAM Keywords

Keyword Definition

RWY .......

Example

Runway

!BNA BNA RWY 18/36 CLSD YYMMDDHHMM−YYMMDDHHMM

TWY .......

Example

Taxiway

!BTV BTV TWY C EDGE LGT OBSC YYMMDDHHMM−YYMMDDHHMM

APRON .....

Example

Apron/Ramp

!BNA BNA APRON NORTH APN E 100FT CLSD YYMMDDHHMM−YYMMDDHHMM

AD .........

Example

Aerodrome

!BET BET AD AP ELK NEAR MOVEMENT AREAS YYMMDDHHMM−YYMMDDHHMM

OBST .......

Example

Obstruction

!SJT SJT OBST MOORED BALLOON WI AN AREA DEFINED AS 1NM RADIUS OF SJT 2430FT (510FT

AGL) FLAGGED YYMMDDHHMM−YYMMDDHHMM

NA V ........

Example

Navigation Aids

!SHV SHV NA V ILS RWY 32 110.3 COMMISSIONED YYMMDDHHMM−PERM

COM .......

Example

Communications

!INW INW COM REMOTE COM OUTLET 122.6 U/S YYMMDDHHMM−YYMMDDHHMM EST

(Note* EST will auto cancel)

SVC ........

Example

Services

!ROA ROA SVC TWR COMMISSIONED YYMMDDHHMM−PERM

AIRSPACE ..

Example

Airspace

!MHV MHV AIRSPACE AEROBATIC ACFT WI AN AREA DEFINED AS 4.3NM RADIUS OF MHV

5500FT−10500FT A VOIDANCE ADZ CTC JOSHUA APP DLY YYMMDDHHMM−YYMMDDHHMM

ODP ........

Example

Obstacle Departure Procedure

!FDC 2/9700 DIK ODP DICKINSON − THEODORE ROOSEVELT RGNL, DICKINSON, ND. TAKEOFF

MINIMUMS AND (OBSTACLE) DEPARTURE PROCEDURES AMDT 1... DEPARTURE PROCEDURE:

RWY 25, CLIMB HEADING 250 TO 3500 BEFORE TURNING LEFT. ALL OTHER DATA REMAINS AS

PUBLISHED. THIS IS TAKEOFF MINIMUMS AND (OBSTACLE) DEPARTURE PROCEDURES, AMDT

1A. YYMMDDHHMM−PERM

SID .........

Example

Standard Instrument Departure

!FDC x/xxxx DFW SID DALLAS/FORT WORTH INTL, DALLAS, TX. PODDE THREE DEPARTURE...

CHANGE NOTES TO READ: RWYS 17C/R, 18L/R: DO NOT EXCEED 240KT UNTIL LARRN. RWYS

35L/C, 36L/R: DO NOT EXCEED 240KT UNTIL KMART YYMMDDHHMM−YYMMDDHHMM

STAR .......

Example

Standard Terminal Arrival

!FDC x/xxxx DCA STAR RONALD REAGAN WASHINGTON NATIONAL,WASHINGTON, DC. WZRRD

TWO ARRIV AL... SHAAR TRANSITION: ROUTE FROM DRUZZ INT TO WZRRD INT NOT AUTHO-

RIZED. AFTER DRUZZ INT EXPECT RADAR VECTORS TO AML VORTAC YYMMDDHHMM−YYM-

MDDHHMM

CHART .....

Example

Chart

!FDC 2/9997 DAL IAP DALLAS LOVE FIELD, DALLAS, TX. ILS OR LOC RWY 31R, AMDT 5... CHART

NOTE: SIMULTANEOUS APPROACH AUTHORIZED WITH RWY 31L. MISSED APPROACH: CLIMB

TO 1000 THEN CLIMBING RIGHT TURN TO 5000 ON HEADING 330 AND CVE R−046 TO FINGR INT/

CVE 36.4 DME AND HOLD. CHART LOC RWY 31L. THIS IS ILS OR LOC RWY 31R, AMDT 5A. YYM-

MDDHHMM−PERM

DATA .......

Example

Data

!FDC 2/9700 DIK ODP DICKINSON − THEODORE ROOSEVELT RGNL, DICKINSON, ND. TAKEOFF

MINIMUMS AND (OBSTACLE) DEPARTURE PROCEDURES AMDT 1... DEPARTURE PROCEDURE:

RWY 25, CLIMB HEADING 250 TO 3500 BEFORE TURNING LEFT. ALL OTHER DATA REMAINS AS

PUBLISHED. THIS IS TAKEOFF MINIMUMS AND (OBSTACLE) DEPARTURE PROCEDURES, AMDT

1A. YYMMDDHHMM−PERM

5−1−6 Preflight

2/20/25 AIM

Keyword Definition

IAP .........

Example

Instrument Approach Procedure

!FDC 2/9997 DAL IAP DALLAS LOVE FIELD, DALLAS, TX. ILS OR LOC RWY 31R, AMDT 5... CHART

NOTE: SIMULTANEOUS APPROACH AUTHORIZED WITH RWY 31L. MISSED APPROACH: CLIMB

TO 1000 THEN CLIMBING RIGHT TURN TO 5000 ON HEADING 330 AND CVE R−046 TO FINGR INT/

CVE 36.4 DME AND HOLD. CHART LOC RWY 31L. THIS IS ILS OR LOC RWY 31R, AMDT 5A. YYM-

MDDHHMM−PERM

VFP ........

Example

Visual Flight Procedures

!FDC X/XXXX JFK VFP JOHN F KENNEDY INTL, NEW YORK, NY . PARKWAY VISUAL RWY 13L/R,

ORIG...WEATHER MINIMUMS 3000 FOOT CEILING AND 3 MILES VISIBILITY . YYMMDDHHMM−

YYMMDDHHMM

ROUTE .....

Example

Route

!FDC x/xxxx ZFW ROUTE ZFW ZKC. V140 SAYRE (SYO) VORTAC, OK TO TULSA (TUL) VORTAC,

OK MEA 4300. YYMMDDHHMM−YYMMDDHHMM EST

SPECIAL ...

Example

Special

!FDC x/xxxx JNU SPECIAL JUNEAU INTERNATIONAL, JUNEAU, AK. LDA−2 RWY 8 AMDT 9 PROCE-

DURE TURN NA. YYMMDDHHMM−YYMMDDHHMM

SECURITY ..

Example

Security

!FDC x/xxxx FDC ...SPECIAL NOTICE... THIS IS A RESTATEMENT OF A PREVIOUSLY ISSUED ADVI-

SORY NOTICE. IN THE INTEREST OF NATIONAL SECURITY AND TO THE EXTENT PRACTICABLE,

PILOTS ARE STRONGLY ADVISED TO A VOID THE AIRSPACE ABOVE, OR IN PROXIMITY TO SUCH

SITES AS POWER PLANTS (NUCLEAR, HYDRO−ELECTRIC, OR COAL), DAMS, REFINERIES, IN-

DUSTRIAL COMPLEXES, MILITARY FACILITIES AND OTHER SIMILAR FACILITIES. PILOTS

SHOULD NOT CIRCLE AS TO LOITER IN THE VICINITY OVER THESE TYPES OF FACILITIES.

GPS Global Positioning System Testing

TESTING !GPS 01/028 ZAB NA V GPS (YPG_AZ GPS 21−06)(INCLUDING WAAS, GBAS, AND ADS−B) MAYNOT

Example BE A VBL WI A276NM RADIUS CENTERED AT 332347N1142221W

(BLH108023) FL400−UNL,

232NM RADIUS AT FL250,

164NM RADIUS AT 100000FT

160NM RADIUS AT 4000FT AGL

126NM RADIUS AT 50FT AGL

DLY 1830−2230

2101281830−2101292230

PRN (GPS)

Example

Pseudo−random noise code used to differentiate GPS satellites. This code allows any receiver to identify exactly

which satellite(s) it is receiving.

!GPS GPS NA V PRN 16 U/S 2109231600−2109242300EST

TBL 5−1−2

Contractions Commonly Found in NOTAMs

A B N .......... Aerodrome Beacon

ACFT ......... Aircraft

A C T .......... Active

A D J .......... Adjacent

A G L .......... Above Ground Level

A L S .......... Approach Light System

A P ........... Airport

A P N .......... Apron

A P P .......... Approach control office or approach

control or approach control service

ARST ......... Arresting (specify (part of) aircraft

arresting equipment)

ASDA ......... Accelerate Stop Distance Available

ASPH ......... Asphalt

AUTH ........ Authorized or authorization

A V B L ......... Available or availability

A VGAS ....... Aviation gasoline

A W O S ........ Automatic Weather Observing System

A Z M .......... Azimuth

B A ........... Braking action

B C N .......... Beacon (aeronautical ground light)

BCST ......... Broadcast

B D R Y ......... Boundary

BLDG ......... Building

B L W .......... Below

B T N .......... Between

C ............. Center (preceded by runway designator

number to identify a parallel runway)

C D ........... Clearance delivery

C I V ........... Civil

C L ........... Centerline

CLSD ......... Close or closed or closing

C O M ......... Communication

CONC ........ Concrete

Preflight 5−1−7

AIM 2/20/25

COND ........ Condition

CONS ......... Continuous

CONST ....... Construction or constructed

CPDLC ........ Controller Pilot Data Link

Communications

C T C .......... Contact

CUST ......... Customs

D A ........... Decision altitude

D E G .......... Degrees

D E P .......... Depart or Departure

D E R .......... Departure end of the runway

D H ........... Decision Height

DIST .......... Distance

D L Y .......... Daily

D P ........... Dew Point Temperature

D P T .......... Depth

DTHR ......... Displaced Runway Threshold

E ............. East or eastern longititude

E B ........... Eastbound

EMERG ....... Emergency

E N E .......... East−northeast

EQPT ......... Equipment

E S E .......... East−southeast

E S T .......... Estimate or estimated or estimation

(message type designator)

E X C .......... Except

F L ............ Flight level

FREQ ......... Frequency

F R I ........... Friday

F S S ........... Flight Service Station

F S T ........... First

F T ............ Feet (dimensional unit)

G ............. Green

G A ........... General aviation

G L D .......... Glider

G N D .......... Ground

G P ........... Glide Path

G R V L ......... Gravel

H E L .......... Helicopter

H G T .......... Height or height above

HLDG ........ Holding

H L P .......... Heliport

H V Y .......... Heavy

I F R ........... Instrument Flight Rules

I L S ........... Instrument Landing System

I M ............ Inner Marker

INOP ......... Inoperative

I N T ........... Intersection

K T ........... Knots

L .............

Left (preceded by runway designator

number to identify a parallel runway)

L A T .......... Latitude

L D A .......... Landing Distance Available

L D G .......... Landing

L E N .......... Length

L G T .......... Light or lighting

LGTD ......... Lighted

L O C .......... Localizer

LONG ........ Longitude

MAINT ....... Maintenance

MBST ......... Microburst

M I L .......... Military

M I N .......... Minutes

M N T .......... Monitor or monitoring or monitored

M O N ......... Monday

M O V ......... Move or moving or movement

N ............. North

N A V A I D ....... Navigational aid

N B ........... Northbound

N D B .......... Nondirectional Radio Beacon

N E ........... Northeast

N E B .......... Northeast bound

N M ........... Nautical Mile/s

N N E .......... North−northeast

N N W ......... North−northwest

N O V .......... November

N W ........... Northwest

N W B ......... Northwest bound

OBSC ......... Obscure or obscured or obscuring

OBST ......... Obstacle

O P N .......... Open or opening or opened

O P S .......... Operations

P A P I .......... Precision Approach Path Indicator

P A R L ......... Parallel

P A X .......... Passenger/s

P C L .......... Pilot Controlled Lighting

P C T .......... Percent

PERM ......... Permanent

P J E ........... Parachute Jumping Activities

P L A .......... Practice Low Approach

P P R .......... Prior Permission Required

P R N .......... Pseudo−random Navigation

P T ............ Procedure Turn

R ............. Red

R ............. Right (preceded by runway designator

number to identify a parallel runway)

R A I ........... Runway Alignment Indicator

R C L .......... Runway Centerline

5−1−8 Preflight

2/20/25 AIM

RCLL ......... Runway Centerline Light

REDL ......... Runway Edge Light

RLLS ......... Runway Lead−in Light System

R M K ......... Remark

R T S .......... Return to Service

R T Z L ......... Runway Touchdown Zone Light(s)

R V R .......... Runway Visual Range

R W Y ......... Runway

R X ........... Receive/Receiver

S ............. South or southern latitude

S A ........... Sand

S A T .......... Saturday

S B ............ Southbound

S E ............ Southeast

S E C .......... Seconds

S F C .......... Surface

S N ........... Snow

S R ............ Sunrise

S S ............ Sunset

S S R .......... Secondary surveillance radar

S S W .......... South−southwest

S T D .......... Standard

S U N .......... Sunday

S W ........... Southwest

S W B .......... Southwest bound

T A R .......... Terminal area surveillance radar

T A X .......... Taxing or taxiing

T D Z .......... Touchdown Zone

TEMPO ....... Temporary or temporarily

T F C .......... Traffic

T H R .......... Threshold

T H U .......... Thursday

TKOF ......... Takeoff

T O D A ......... Take−off Distance Available

T O R A ......... Take−off Run Available

T R G .......... Training

T U E .......... Tuesday

T W R .......... Aerodrome Control Tower

T W Y ......... Taxiway

T X ........... Taxilane

U / S ........... Unserviceable

U A S .......... Unmanned Aircraft System

U N L .......... Unlimited

UNREL ....... Unreliable

V I S ........... Visibility

V O R .......... VHF Omni-Directional Radio Range

V O R T A C ...... VOR and TACAN (collocated)

V O T .......... VOR Test Facility

W ............ West or western longitude

W B ........... Westbound

W D I .......... Wind Direction Indicator

W E D ......... Wednesday

W I ........... Within

W I D .......... Width or wide

W I P .......... Work in progress

W N W ......... West−northwest

W S ........... Wind shear

W S W ......... West−southwest

5−1−4. Operational Information System (OIS)

a. The FAA’s Air Traffic Control System Command Center (ATCSCC) maintains a website with near

real−time National Airspace System (NAS) status information. NAS operators are encouraged to access the

website at http://www.fly.faa.gov prior to filing their flight plan.

b. The website consolidates information from advisories. An advisory is a message that is disseminated

electronically by the ATCSCC that contains information pertinent to the NAS.

1. Advisories are normally issued for the following items:

(a) Ground Stops.

(b) Ground Delay Programs.

(c) Route Information.

(d) Plan of Operations.

(e) Facility Outages and Scheduled Facility Outages.

(f) V olcanic Ash Activity Bulletins.

(g) Special Traffic Management Programs.

2. This list is not all−inclusive. Any time there is information that may be beneficial to a large number of

people, an advisory may be sent. Additionally, there may be times when an advisory is not sent due to workload

or the short length of time of the activity.

Preflight 5−1−9

AIM 2/20/25

3. Route information is available on the website and in specific advisories. Some route information, subject

to the 56−day publishing cycle, is located on the “OIS” under “Products,” Route Management Tool (RMT), and

“What’s New” Playbook. The RMT and Playbook contain routings for use by Air Traffic and NAS operators

when they are coordinated “real−time” and are then published in an ATCSCC advisory.

4. Route advisories are identified by the word “Route” in the header; the associated action is required

(RQD), recommended (RMD), planned (PLN), or for your information (FYI). Operators are expected to file

flight plans consistent with the Route RQD advisories.

5. Electronic System Impact Reports are on the intranet at http://www.atcscc.faa.gov/ois/ under “System

Impact Reports.” This page lists scheduled outages/events/projects that significantly impact the NAS; for

example, runway closures, air shows, and construction projects. Information includes anticipated delays and

traffic management initiatives (TMI) that may be implemented.

5−1−5. Flight Plan − VFR Flights

(See Appendix 4, F AA Form 7233−4 – International Flight Plan)

a. The requirements for the filing and activation of VFR flight plans can vary depending in which airspace

the flight is operating. Pilots are responsible for activating flight plans with a Flight Service Station. Control

tower personnel do not automatically activate VFR flight plans.

1. Within the continental U.S., a VFR flight plan is not normally required.

2. VFR flights (except for DoD and law enforcement flights) into an Air Defense Identification Zone

(ADIZ) are required to file DVFR flight plans.

NOTE−

Detailed ADIZ procedures are found inSection 6, National Security and Interception Procedures, of this chapter. (See 14

CFR part 99).

3. Flights within the Washington, DC Special Flight Rules Area have additional requirements that must be

met. Visit http://www.faasafety.gov for the required Special Awareness Training that must be completed before

flight within this area.

4. VFR flight to an international destination requires a filed and activated flight plan.

NOTE−

ICAO flight plan guidance is published in ICAO Document 4444 P ANS−ATM Appendix 2.

b. It is strongly recommended that a VFR flight plan be filed with a Flight Service Station or equivalent flight

plan filing service. When filing, pilots must use FAA Form 7233−4, International Flight Plan or DD Form 1801.

Only DoD users, and civilians who file stereo route flight plans, may use FAA Form 7233−1, Flight Plan. Pilots

may take advantage of advances in technology by filing their flight plans using any available electronic means.

Activating the flight plan will ensure that you receive VFR Search and Rescue services.

c. When a stopover flight is anticipated, it is recommended that a separate flight plan be filed for each leg of

the flight.

d. Pilots are encouraged to activate their VFR flight plans with Flight Service by the most expeditious means

possible. This may be via radio or other electronic means. VFR flight plan proposals are normally retained for

two hours following the proposed time of departure.

e. Pilots may also activate a VFR flight plan by using an assumed departure time. This assumed departure time

will cause the flight plan to become active at the designated time. This may negate the need for communication

with a flight service station or flight plan filing service upon departure. It is the pilot’s responsibility to revise

his actual departure time, time en route, or ETA with flight service.

NOTE−

Pilots are strongly advised to remain mindful when using an assumed departure time. If not updated, search and rescue

activities will be based on the assumed departure time.

5−1−10 Preflight

2/20/25 AIM

f. U.S. air traffic control towers do not routinely activate VFR flight plans. Foreign pilots especially must be

mindful of the need to communicate directly with a flight service station, or use an assumed departure time

procedure clearly communicated with the flight plan filing service.

g. Although position reports are not required for VFR flight plans, periodic reports to FSSs along the route

are good practice. Such contacts permit significant information to be passed to the transiting aircraft and also

serve to check the progress of the flight should it be necessary for any reason to locate the aircraft.

h. Pilots flying VFR should fly an appropriate cruising altitude for their direction of flight.

i. When filing a VFR Flight plan, indicate the appropriate aircraft equipment capability as prescribed for an

IFR flight plan.

REFERENCE−

AIM, Para 5−1−6, IFR Flights.

j. ATC radar history data can be useful in finding a downed or missing aircraft; therefore, surveillance

equipment should be listed in Item 18. Pilots using commercial GPS tracking services are encouraged to note

the specific service in Item 19 N/ (survival equip remarks) of FAA Form 7233−4 or DD Form 1801.

5−1−6. Flight Plan − IFR Flights

(See Appendix 4, F AA Form 7233−4 – International Flight Plan)

a. General

1. Use of FAA Form 7233−4 or DD Form 1801 is mandatory for:

(a) Assignment of RNA V SIDs and STARs or other PBN routing,

(b) All civilian IFR flights that will depart U.S. domestic airspace, and

(c) Domestic IFR flights except military/DoD and civilians who file stereo route flight plans.

(d) All military/DoD IFR flights that will depart U.S. controlled airspace.

2. Military/DoD flights using FAA Form 7233−1, or DD Form 175, may not be eligible for assignment of

RNA V SIDs or STARs. Military flights desiring assignment of these procedures should file using FAA Form

7233−4 or DD 1801, as described in this section.

3. When filing an IFR flight plan using FAA Form 7233−4 or DD Form 1801, it is recommended that filers

include all operable navigation, communication, and surveillance equipment capabilities by adding appropriate

equipment qualifiers as shown in Appendix 4, FAA Form 7233−4, International Flight Plan.

4. ATC issues clearances based on aircraft capabilities filed in Items 10 and 18 of FAA Form 7233−4 or DD

1801. Operators should file all capabilities for which the aircraft and crew is certified, capable, and authorized.

PBN/capability must be filed in Item 18, Other Information. When filing a capability, A TC expects filers to use

that capability; for example, answer a SATVOICE call from ATC if code M1 or M3 is filed in Item 10a.

5. Prior to departure from within, or prior to entering controlled airspace, a pilot must submit a complete

flight plan and receive an air traffic clearance, if weather conditions are below VFR minimums. IFR flight plans

may be submitted to an FSS or flight plan filing service.

6. Pilots should file IFR flight plans at least 30 minutes prior to estimated time of departure to preclude

possible delay in receiving a departure clearance from ATC.

7. In order to provide FAA traffic management units’ strategic route planning capabilities, nonscheduled

operators conducting IFR operations above FL 230 are requested to voluntarily file IFR flight plans at least 4

hours prior to estimated time of departure (ETD).

8. To minimize your delay in entering Class B, Class C, Class D, and Class E surface areas at destination

when IFR weather conditions exist or are forecast at that airport, an IFR flight plan should be filed before

Preflight 5−1−11

AIM 2/20/25

departure. Otherwise, a 30−minute delay is not unusual in receiving an ATC clearance because of time spent in

processing flight plan data.

9. Traffic saturation frequently prevents control personnel from accepting flight plans by radio. In such

cases, the pilot is advised to contact a flight plan filing service for the purpose of filing the flight plan.

10. When requesting an IFR clearance, it is highly recommended that the departure airport be identified by

stating the city name and state and/or the airport location identifier in order to clarify to ATC the exact location

of the intended airport of departure.

11. Multiple versions of flight plans for the same flight may lead to unsafe conditions and errors within the

air traffic system. Pilots must not file more than one flight plan for the same flight without ensuring that the

previous flight plan has been successfully removed.

12. When a pilot is aware that the possibility for multiple flight plans on the same aircraft may exist,

ensuring receipt of a full route clearance will help mitigate chances of error.

REFERENCE−

AIM, Para 5−1−12, Change in Flight Plan.

AIM, Para 5−1−13, Change in Proposed Departure Time.

b. Airways and Jet Routes Depiction on Flight Plan

1. It is vitally important that the route of flight be accurately and completely described in the flight plan.

To simplify definition of the proposed route, and to facilitate ATC, pilots are requested to file via airways or jet

routes established for use at the altitude or flight level planned.

2. If flight is to be conducted via designated airways or jet routes, describe the route by indicating the type

and number designators of the airway(s) or jet route(s) requested. If more than one airway or jet route is to be

used, clearly indicate points of transition. If the transition is made at an unnamed intersection, show the next

succeeding NA V AID or named intersection on the intended route and the complete route from that point.

Reporting points may be identified by using authorized name/code as depicted on appropriate aeronautical

charts. The following two examples illustrate the need to specify the transition point when two routes share more

than one transition fix.

EXAMPLE−

1. ALB J37 BUMPY J14 BHM Spelled out: from Albany, New York, via Jet Route 37 transitioning to Jet Route 14 at BUMPY

intersection, thence via Jet Route 14 to Birmingham, Alabama.

2. ALB J37 ENO J14 BHM Spelled out: from Albany, New York, via Jet Route 37 transitioning to Jet Route 14 at Smyrna

VORTAC (ENO) thence via Jet Route 14 to Birmingham, Alabama.

3. The route of flight may also be described by naming the reporting points or NA V AIDs over which the

flight will pass, provided the points named are established for use at the altitude or flight level planned.

EXAMPLE−

BWI V44 SWANN V433 DQO Spelled out: from Baltimore−W ashington International, via Victor 44 to Swann intersection,

transitioning to Victor 433 at Swann, thence via Victor 433 to Dupont.

4. When the route of flight is defined by named reporting points, whether alone or in combination with

airways or jet routes, and the navigational aids (VOR, VORTAC, TACAN, NDB) to be used for the flight are

a combination of different types of aids, enough information should be included to clearly indicate the route

requested.

EXAMPLE−

LAX J5 LKV J3 GEG YXC FL 330 J500 VLR J515 YWG Spelled out: from Los Angeles International via Jet Route 5

Lakeview, Jet Route 3 Spokane, direct Cranbrook, British Columbia VOR/DME, Flight Level 330 Jet Route 500 to Langruth,

Manitoba VORTAC, Jet Route 515 to Winnipeg, Manitoba.

5. When filing IFR, it is to the pilot’s advantage to file a preferred route.

REFERENCE−

Preferred IFR Routes are described and tabulated in the Chart Supplement.

5−1−12 Preflight

2/20/25 AIM

Additionally available at U.S.

http://www.fly.faa.gov/Products/Coded_Departure_Routes/NFDC_Preferred_Routes_Database/nfdc_preferred_routes_database.html.

6. ATC may issue a SID or a STAR, as appropriate.

REFERENCE−

AIM, Para 5−2−9, Instrument Departure Procedures (DP) − Obstacle Departure Procedures (ODP) and Standard Instrument Departures (SID), and

Diverse Vector Areas (DVA).

AIM, Para 5−4−1, Standard Terminal Arrival (STAR) Procedures.

NOTE−

Pilots not desiring an RNAV SID or RNAV STAR should enter in Item #18, PBN code: NAV/RNV A0 and/or D0.

c. Direct Flights

1. All or any portions of the route which will not be flown on the radials or courses of established airways

or routes, such as direct route flights, must be defined by indicating the radio fixes over which the flight will pass.

Fixes selected to define the route must be those over which the position of the aircraft can be accurately

determined. Such fixes automatically become compulsory reporting points for the flight, unless advised

otherwise by ATC. Only those navigational aids established for use in a particular structure; i.e., in the low or

high structures, may be used to define the en route phase of a direct flight within that altitude structure.

2. The azimuth feature of VOR aids and the azimuth and distance (DME) features of VORTAC and TACAN

aids are assigned certain frequency protected areas of airspace which are intended for application to established

airway and route use, and to provide guidance for planning flights outside of established airways or routes. These

areas of airspace are expressed in terms of cylindrical service volumes of specified dimensions called “class

limits” or “categories.”

REFERENCE−

AIM, Para 1−1−8, Navigational Aid (NAVAID) Service Volumes.

3. An operational service volume has been established for each class in which adequate signal coverage and

frequency protection can be assured. To facilitate use of VOR, VORTAC, or TACAN aids, consistent with their

operational service volume limits, pilot use of such aids for defining a direct route of flight in controlled airspace

should not exceed the following:

(a) Operations above FL 450 − Use aids not more than 200 NM apart. These aids are depicted on en route

high altitude charts.

(b) Operation off established routes from 18,000 feet MSL to FL 450 − Use aids not more than 260 NM

apart. These aids are depicted on en route high altitude charts.

(c) Operation off established airways below 18,000 feet MSL − Use aids not more than 80 NM apart.

These aids are depicted on en route low altitude charts.

(d) Operation off established airways between 14,500 feet MSL and 17,999 feet MSL in the

conterminous U.S. − (H) facilities not more than 200 NM apart may be used.

4. Increasing use of self −contained airborne navigational systems which do not rely on the

VOR/VORTAC/TACAN system has resulted in pilot requests for direct routes which exceed NA V AID service

volume limits.

5. At times, ATC will initiate a direct route in a surveillance environment which exceeds NA V AID service

volume limits. Pilots must adhere to the altitude specified in the clearance.

6. Appropriate airway or jet route numbers may also be included to describe portions of the route to be

flown.

EXAMPLE−

MDW V262 BDF V10 BRL STJ SLN GCK Spelled out: from Chicago Midway Airport via Victor 262 to Bradford, Victor 10

to Burlington, Iowa, direct St. Joseph, Missouri, direct Salina, Kansas, direct Garden City, Kansas.

NOTE−

When route of flight is described by radio fixes, the pilot will be expected to fly a direct course between the points named.

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AIM 2/20/25

7. Pilots are reminded that they are responsible for adhering to obstruction clearance requirements on those

segments of direct routes that are outside of controlled airspace and A TC surveillance capability. The MEAs and

other altitudes shown on IFR en route charts pertain to those route segments within controlled airspace, and those

altitudes may not meet obstruction clearance criteria when operating off those routes.

NOTE−

Refer to 14 CFR 91.177 for pilot responsibility when flying random point to point routes.

d. Area Navigation (RNA V)/Global Navigation Satellite System (GNSS)

1. When not being radar monitored, GNSS−equipped RNA V aircraft on random RNA V routes must be

cleared via or reported to be established on a point−to−point route.

(a) The points must be published NA V AIDs, waypoints, fixes or airports recallable from the aircraft’s

navigation database. The points must be displayed on controller video maps or depicted on the controller chart

displayed at the control position. When applying non−radar separation the maximum distance between points

must not exceed 500 miles.

(b) ATC will protect 4 miles either side of the route centerline.

(c) Assigned altitudes must be at or above the highest MIA along the projected route segment being

flown, including the protected airspace of that route segment.

2. Pilots of aircraft equipped with approved area navigational equipment may file for RNA V routes

throughout the National Airspace System in accordance with the following procedures:

(a) File airport−to−airport flight plans.

(b) File the appropriate indication of RNA V and/or RNP capability in the flight plan.

(c) Plan the random route portion of the flight plan to begin and end over appropriate arrival and departure

transition fixes or appropriate navigation aids for the altitude stratum within which the flight will be conducted.

The use of normal preferred departure and arrival routes (DP/STAR), where established, is recommended.

(d) File route structure transitions to and from the random route portion of the flight.

(e) Define the random route by waypoints. File route description waypoints by using degree distance

fixes based on navigational aids which are appropriate for the altitude stratum.

(f) File a minimum of one route description waypoint for each ARTCC through whose area the random

route will be flown. These waypoints must be located within 200 NM of the preceding center’s boundary.

(g) File an additional route description waypoint for each turn point in the route.

(h) Plan additional route description waypoints as required to ensure accurate navigation via the filed

route of flight. Navigation is the pilot’s responsibility unless ATC assistance is requested.

(i) Plan the route of flight so as to avoid prohibited and restricted airspace by 3 NM unless permission

has been obtained to operate in that airspace and the appropriate ATC facilities are advised.

NOTE−

To be approved for use in the National Airspace System, RNAV equipment must meet system availability, accuracy, and

airworthiness standards. For additional information and guidance on RNAV equipment requirements see Advisory Circular

(AC) 20−138 Airworthiness Approval of Positioning and Navigation Systems and AC 90−100 U.S. Terminal and En Route

Area Navigation (RNAV) Operations.

3. Pilots of aircraft equipped with latitude/longitude coordinate navigation capability, independent of

VOR/TACAN references, may file for random RNA V using the following procedures:

(a) File airport−to−airport flight plans prior to departure.

(b) File the appropriate RNA V capability certification suffix in the flight plan.

(c) Plan the random route portion of the flight to begin and end over published departure/arrival transition

fixes or appropriate navigation aids for airports without published transition procedures. The use of preferred

departure and arrival routes, such as DP and STAR, where established, is recommended.

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2/20/25 AIM

(d) Plan the route of flight so as to avoid prohibited and restricted airspace by 3 NM unless permission

has been obtained to operate in that airspace and the appropriate ATC facility is advised.

(e) Define the route of flight after the departure fix, including each intermediate fix (turnpoint) and the

arrival fix for the destination airport in terms of latitude/longitude coordinates plotted to the nearest minute or

in terms of Navigation Reference System (NRS) waypoints. For latitude/longitude filing the arrival fix must be

identified by both the latitude/longitude coordinates and a fix identifier.

EXAMPLE−

MIA1 SRQ2 3407/106153 3407/11546 TNP4 LAX5

1 Departure airport.

2 Departure fix.

3 Intermediate fix (turning point).

4 Arrival fix.

5 Destination airport.

or

ORD1 IOW2 KP49G3 KD34U4 KL16O5 OAL6 MOD27 SFO8

1 Departure airport.

2 Transition fix.

3 Minneapolis ARTCC waypoint.

4 Denver ARTCC Waypoint.

5 Los Angeles ARTCC waypoint.

6 Transition fix.

7 Arrival.

8 Destination airport.

(f) Record latitude/longitude coordinates by two or four figures describing latitude in degrees followed

by an N or S, followed by 3 or 5 digits longitude, followed by an E or W. Separate latitude and longitude with

a solidus “/.” Use leading zeros if necessary.

(g) File at FL 390 or above for the random RNA V portion of the flight.

(h) Fly all routes/route segments on Great Circle tracks.

(i) Make any inflight requests for random RNA V clearances or route amendments to an en route ATC

facility.

5−1−7. Flight Plans For Military/DoD Use Only

(See Appendix 4, F AA Form 7233−1, Flight Plan)

Within U.S. controlled airspace, FAA Form 7233−1 or DD Form 175 may be used by DoD aircraft. However,

use of the DD Form 1801 by DoD aircraft is recommended for IFR flights and is mandatory for:

a. Any flight that will depart U.S. controlled airspace.

b. Any flight requesting routing that requires Performance Based Navigation.

c. Any flight requesting services that require filing of capabilities only supported in the international flight

plan.

NOTE−

1. The order of flight plan elements in DD Form 175 is equivalent to that of F AA Form 7233−1.

2. Civilians who file stereo route flight plans, may use F AA Form 7233−1, Flight Plan.

5−1−8. Flight Plan – Defense VFR (DVFR) Flights

VFR flights (except for DoD and law enforcement flights) into an ADIZ are required to file DVFR flight plans

for security purposes. Detailed ADIZ procedures are found in Section 6, National Security and Interception

Procedures, of this chapter.

Preflight 5−1−15

AIM 2/20/25

REFERENCE−

14 CFR part 99, Security Control for Air Traffic.

a. DVFR flight plans must be filed using FAA Form 7233−4 or DD Form 1801.

b. Enter the letter “D” in Item 8, Type of Flight, of FAA Form 7233−4 or DD Form 1801.

c. DVFR flights where pilots decline search and rescue coverage must clearly indicate “NORIV” in Item 18

following the indicator “RMK/.” This flight plan must still be activated in order to properly notify NORAD,

however no flight plan cancellation will be expected.

EXAMPLE−

RMK/NORIV

5−1−9. Single Flights Conducted With Both VFR and IFR Flight Plans

a. Flight plans which combine VFR operation on an active VFR flight plan for one portion of a flight, and

IFR for another portion, sometimes known as a composite flight plan, cannot be accepted or processed by current

en route automation systems.

b. Pilots are free to operate VFR in VFR conditions prior to accepting an IFR clearance from the appropriate

control facility, or may cancel an IFR clearance and proceed VFR as desired. However, if a pilot desires to be

on an active VFR flight plan, with search and rescue provisions, for the portion of flight not conducted under

an IFR clearance, a separate VFR flight plan must be filed, activated, and closed.

c. If a pilot desires to be on an active VFR flight plan prior to or following the IFR portion of the flight, that

flight plan must be filed and processed as a distinct and separate flight plan. The VFR flight plan must be opened

and closed with either a Flight Service Station or other service provider having the capability to open and close

VFR flight plans. Air Traffic Control does not have the ability to determine if an aircraft is operating on an active

VFR flight plan and cannot process the activation or cancellation of a VFR flight plan.

d. Pilots may propose to commence the IFR portion of flight at a defined airborne point. This airborne point,

or fix, is entered as the departure point in Item 13 of FAA Form 7233−4 or DD Form 1801.

e. Pilots may indicate in the IFR flight plan the intention to terminate the IFR portion of flight at any defined

airborne point. The airborne point, or fix, is entered as the destination point in Item 16 of FAA Form 7233−4 or

DD Form 1801.

f. Prior to beginning the IFR portion of flight, a pilot must receive an IFR clearance from the appropriate

control facility.

g. If the pilot does not desire further clearance after reaching the clearance limit, he or she must advise ATC

to cancel the IFR clearance.

5−1−10. IFR Operations to High Altitude Destinations

a. Pilots planning IFR flights to airports located in mountainous terrain are cautioned to consider the necessity

for an alternate airport even when the forecast weather conditions would technically relieve them from the

requirement to file one.

REFERENCE−

14 CFR section 91.167.

AIM, Para 4−1−19, Tower En Route Control (TEC).

b. The FAA has identified three possible situations where the failure to plan for an alternate airport when

flying IFR to such a destination airport could result in a critical situation if the weather is less than forecast and

sufficient fuel is not available to proceed to a suitable airport.

1. An IFR flight to an airport where the Min imum Descent Altitudes (MDAs) or landing visibility

minimums for all instrument approaches are higher than the forecast weather minimums specified in 14 CFR

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section 91.167(b). For example, there are 3 high altitude airports in the U.S. with approved instrument approach

procedures where all of the MDAs are greater than 2,000 feet and/or the landing visibility minimums are greater

than 3 miles (Bishop, California; South Lake Tahoe, California; and Aspen−Pitkin Co./Sardy Field, Colorado).

In the case of these airports, it is possible for a pilot to elect, on the basis of forecasts, not to carry sufficient fuel

to get to an alternate when the ceiling and/or visibility is actually lower than that necessary to complete the

approach.

2. A small number of other airports in mountainous terrain have MDAs which are slightly (100 to 300 feet)

below 2,000 feet AGL. In situations where there is an option as to whether to plan for an alternate, pilots should

bear in mind that just a slight worsening of the weather conditions from those forecast could place the airport

below the published IFR landing minimums.

3. An IFR flight to an airport which requires special equipment; i.e., DME, glide slope, etc., in order to make

the available approaches to the lowest minimums. Pilots should be aware that all other minimums on the

approach charts may require weather conditions better than those specified in 14 CFR section 91.167(b). An

inflight equipment malfunction could result in the inability to comply with the published approach procedures

or, again, in the position of having the airport below the published IFR landing minimums for all remaining

instrument approach alternatives.

5−1−11. Flights Outside U.S. Territorial Airspace

a. When conducting flights, particularly extended flights, outside the U.S. and its territories, full account

should be taken of the amount and quality of air navigation services available in the airspace to be traversed.

Every effort should be made to secure information on the location and range of navigational aids, availability

of communications and meteorological services, the provision of air traffic services, including alerting service,

and the existence of search and rescue services.

b. Pilots should remember that there is a need to continuously guard the VHF emergency frequency 121.5

MHz when on long over-water flights, except when communications on other VHF channels, equipment

limitations, or cockpit duties prevent simultaneous guarding of two channels. Guarding of 121.5 MHz is

particularly critical when operating in proximity to Flight Information Region (FIR) boundaries, for example,

operations on Route R220 between Anchorage and Tokyo, since it serves to facilitate communications with

regard to aircraft which may experience in-flight emergencies, communications, or navigational difficulties.

REFERENCE−

ICAO Annex 10, Vol II, Paras 5.2.2.1.1.1 and 5.2.2.1.1.2.

c. The filing of a flight plan, always good practice, takes on added significance for extended flights outside

U.S. airspace and is, in fact, usually required by the laws of the countries being visited or overflown. It is also

particularly important in the case of such flights that pilots leave a complete itinerary and schedule of the flight

with someone directly concerned and keep that person advised of the flight’s progress. If serious doubt arises

as to the safety of the flight, that person should first contact the appropriate FSS. Round Robin Flight Plans to

Canada and Mexico are not accepted.

d. All pilots should review the foreign airspace an d entry restrictions published in the appropriate

Aeronautical Information Publication (AIP) during the flight planning process. Foreign airspace penetration

without official authorization can involve both danger to the aircraft and the imposition of severe penalties and

inconvenience to both passengers and crew. A flight plan on file with ATC authorities does not necessarily

constitute the prior permission required by certain other authorities. The possibility of fatal consequences cannot

be ignored in some areas of the world.

e. Current NOTAMs for foreign locations must also be reviewed. International Notices regarding specific

countries may be obtained through the Federal NOTAM System (FNS) NOTAM Search External Links or the

Air Traffic Plans and Publications website. For additional flight information at foreign locations, pilots should

also review the FAA’s Prohibitions, Restrictions, and Notices website at

https://www.faa.gov/air_traffic/publications/us_restrictions/.

Preflight 5−1−17

AIM 2/20/25

f. When customs notification to foreign locations is required, it is the responsibility of the pilot to arrange for

customs notification in a timely manner.

g. Aircraft arriving to locations in U.S. territorial airspace must meet the entry requirements as described in

AIM Section 6, National Security and Interception Procedures.

5−1−12. Change in Flight Plan

a. In addition to altitude or flight level, destination and/or route changes, increasing or decreasing the speed

of an aircraft constitutes a change in a flight plan. Therefore, at any time the average true airspeed at cruising

altitude between reporting points varies or is expected to vary from that given in the flight plan by plus or minus

5 percent, or 10 knots, whichever is greater, ATC should be advised.

b. All changes to existing flight plans should be completed more than 46 minutes prior to the proposed

departure time. Changes must be made with the initial flight plan service provider. If the initial flight plan’s

service provider is unavailable, filers may contact an ATC facility or FSS to make the necessary revisions. Any

revision 46 minutes or less from the proposed departure time must be coordinated through an ATC facility or

FSS.

5−1−13. Change in Proposed Departure Time

a. To prevent computer saturation in the en route environment, parameters have been established to delete

proposed departure flight plans which have not been activated. Most centers have this parameter set so as to delete

these flight plans a minimum of 2 hours after the proposed departure time or Expect Departure Clearance Time

(EDCT). To ensure that a flight plan remains active, pilots whose actual departure time will be delayed 2 hours

or more beyond their filed departure time, are requested to notify ATC of their new proposed departure time.

b. Due to traffic saturation, ATC personnel frequently will be unable to accept these revisions via radio. It is

recommended that you forward these revisions to a flight plan service provider or FSS.

5−1−14. Closing VFR/DVFR Flight Plans

A pilot is responsible for ensuring that his/her VFR or DVFR flight plan is canceled. You should close your flight

plan with the nearest FSS, or if one is not available, you may request any ATC facility to relay your cancellation

to the FSS. Control towers do not automatically close VFR or DVFR flight plans since they do not know if a

particular VFR aircraft is on a flight plan. If you fail to report or cancel your flight plan within 1/2 hour after your

ETA, search and rescue procedures are started.

REFERENCE−

14 CFR Section 91.153.

14 CFR Section 91.169.

5−1−15. Canceling IFR Flight Plan

a. 14 CFR sections 91.153 and 91.169 include the statement “When a flight plan has been activated, the

pilot-in-command, upon canceling or completing the flight under the flight plan, must notify an FAA Flight

Service Station or ATC facility.”

b. An IFR flight plan may be canceled at any time the flight is operating in VFR conditions outside Class A

airspace by pilots stating “CANCEL MY IFR FLIGHT PLAN” to the controller or air/ground station with which

they are communicating. Immediately after canceling an IFR flight plan, a pilot should take the necessary action

to change to the appropriate air/ground frequency, VFR radar beacon code and VFR altitude or flight level.

c. ATC separation and information services will be discontinued, including radar services (where applicable).

Consequently, if the canceling flight desires VFR radar advisory service, the pilot must specifically request it.

NOTE−

Pilots must be aware that other procedures may be applicable to a flight that cancels an IFR flight plan within an area where

a special program, such as a designated TRSA, Class C airspace, or Class B airspace, has been established.

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d. If a DVFR flight plan requirement exists, the pilot is responsible for filing this flight plan to replace the

canceled IFR flight plan. If a subsequent IFR operation becomes necessary, a new IFR flight plan must be filed

and an ATC clearance obtained before operating in IFR conditions.

e. If operating on an IFR flight plan to an airport with a functioning control tower, the flight plan is

automatically closed upon landing.

f. If operating on an IFR flight plan to an airport where there is no functioning control tower, the pilot must

initiate cancellation of the IFR flight plan. This can be done after landing if there is a functioning FSS or other

means of direct communications with ATC. In the event there is no FSS and/or air/ground communications with

ATC is not possible below a certain altitude, the pilot should, weather conditions permitting, cancel the IFR flight

plan while still airborne and able to communicate with ATC by radio. This will not only save the time and expense

of canceling the flight plan by telephone but will quickly release the airspace for use by other aircraft.

5−1−16. RNAV and RNP Operations

a. During the pre−flight planning phase the availability of the navigation infrastructure required for the

intended operation, including any non −RNA V contingencies, must be confirmed for the period of intended

operation. Availability of the onboard navigation equipment necessary for the route to be flown must be

confirmed. Pilots are reminded that on composite VFR to IFR flight plan, or on an IFR clearance, while flying

unpublished departures via RNA V into uncontrolled airspace, the PIC is responsible for terrain and obstruction

clearance until reaching the MEA/MIA/MV A/OROCA.

NOTE−

OROCA is a published altitude which provides 1,000 feet of terrain and obstruction clearance in the U.S. (2,000 feet of

clearance in designated mountainous areas). These altitudes are not assessed for NAVAID signal coverage, air traffic

control surveillance, or communications coverage, and are published for general situational awareness, flight planning and

in−flight contingency use.

b. If a pilot determines a specified RNP level cannot be achieved, revise the route or delay the operation until

appropriate RNP level can be ensured.

c. The onboard navigation database must be current and appropriate for the region of intended operation and

must include the navigation aids, waypoints, and coded terminal airspace procedures for the departure, arrival

and alternate airfields.

d. During system initialization, pilots of aircraft equipped with a Flight Management System or other

RNA V−certified system, must confirm that the navigation database is current, and verify that the aircraft position

has been entered correctly. Flight crews should crosscheck the cleared flight plan against charts or other

applicable resources, as well as the navigation system textual display and the aircraft map display. This process

includes confirmation of the waypoints sequence, reasonableness of track angles and distances, any altitude or

speed constraints, and identification of fly−by or fly−over waypoints. A procedure must not be used if validity

of the navigation database is in doubt.

e. Prior to commencing takeoff, the flight crew must verify that the RNA V system is operating correctly and

the correct airport and runway data have been loaded.

f. During the pre−flight planning phase RAIM prediction must be performed if TSO−C129() equipment is

used to solely satisfy the RNA V and RNP requirement. GPS RAIM availability must be confirmed for the

intended route of flight (route and time) using current GPS satellite information. In the event of a predicted,

continuous loss of RAIM of more than five (5) minutes for any part of the intended flight, the flight should be

Preflight 5−1−19

AIM 2/20/25

delayed, canceled, or re−routed where RAIM requirements can be met. Operators may satisfy the predictive

RAIM requirement through any one of the following methods:

1. Operators may monitor the status of each satellite in its plane/slot position, by accounting for the latest

GPS constellation status (for example, NOTAMs or NANUs), and compute RAIM availability using

model−specific RAIM prediction software;

2. Operators may use the Service Availability Prediction Tool (SAPT) on the FAA en route and terminal

RAIM prediction website;

3. Operators may contact a Flight Service Station to obtain non−precision approach RAIM;

4. Operators may use a third party interface, incorporating FAA/VOLPE RAIM prediction data without

altering performance values, to predict RAIM outages for the aircraft’s predicted flight path and times;

5. Operators may use the receiver’s installed RAIM prediction capability (for TSO−C129a/Class A1/B1/C1

equipment) to provide non−precision approach RAIM, accounting for the latest GPS constellation status (for

example, NOTAMs or NANUs). Receiver non−precision approach RAIM should be checked at airports spaced

at intervals not to exceed 60 NM along the RNA V 1 procedure’s flight track. “Terminal” or “Approach” RAIM

must be available at the ETA over each airport checked; or,

6. Operators not using model−specific software or FAA/VOLPE RAIM data will need FAA operational

approval.

NOTE−

If TSO−C145/C146 equipment is used to satisfy the RNAV and RNP requirement, the pilot/operator need not perform the

prediction if WAAS coverage is confirmed to be available along the entire route of flight. Outside the U.S. or in areas where

WAAS coverage is not available, operators using TSO−C145/C146 receivers are required to check GPS RAIM availability.

5−1−17. Cold Temperature Operations

a. Pilots should begin planning for cold temperature operations during the preflight planning phase. Cold

temperatures produce barometric altimetry errors, which affect instrument flight procedures. Currently there are

two temperature limitations that may be published in the notes box of the middle briefing strip on an instrument

approach procedure (IAP). The two published temperature limitations are:

1. A temperature range limitation associated with the use of baro −VNA V that may be published on an

United States PBN IAP titled RNA V (GPS) or RNA V (RNP); and/or

2. A Cold Temperature Airport (CTA) limitation designated by a snowflake ICON and temperature in

Celsius (C) that is published on every IAP for the airfield.

b. Pilots should request the lowest forecast temperature +/− 1 hour for arrival and departure operations. If the

temperature is forecast to be outside of the baro−VNA V or at or below the CTA temperature limitation, consider

the following:

1. When using baro−VNA V with an aircraft that does not have an automated temperature compensating

function, pilots should plan to use the appropriate minima and/or IAP.

(a) The LNA V/VNA V line of minima on an RNA V (GPS) may not be used without an approved

automated temperature compensating function if the temperature is outside of the baro −VNA V temperature

range limitation. The LNA V minima may be used.

(b) The RNA V (RNP) procedure may not be accomplished without an approved automated temperature

compensating function if the temperature is outside of the baro−VNA V temperature range limitation.

2. If the temperature is forecast to be at or below the published CTA temperature, pilots should calculate

a correction for the appropriate segment/s or a correction for all the segments if using the “All Segments Method.”

Pilots should review the operating procedures for the aircraft’s temperature compensating system when planning

5−1−20 Preflight

2/20/25 AIM

to use the system for any cold temperature corrections. Any planned altitude correction for the intermediate

and/or missed approach holding segments must be coordinated with ATC. Pilots do not have to advise ATC of

a correction in the final segment.

NOTE−

The charted baro−VNAV temperature range limitation does not apply to pilots operating aircraft with an airworthiness

approval to conduct an RNAV (GPS) approach to LNAV/VNAV minimums with the use of SBAS vertical guidance.

REFERENCE−

AIM, Chapter 7, Section 3, Cold Temperature Barometric Altimeter Errors, Setting Procedures, and Cold Temperature Airports (CTA).

Preflight 5−1−21

2/20/25 AIM

Section 2. Departure Procedures

5−2−1. Pre-taxi Clearance Procedures

a. Certain airports have established pre-taxi clearance programs whereby pilots of departing instrument flight

rules (IFR) aircraft may elect to receive their IFR clearances before they start taxiing for takeoff. The following

provisions are included in such procedures:

1. Pilot participation is not mandatory.

2. Participating pilots call clearance delivery or ground control not more than 10 minutes before proposed

taxi time.

3. IFR clearance (or delay information, if clearance cannot be obtained) is issued at the time of this initial

call-up.

4. When the IFR clearance is received on clearance delivery frequency, pilots call ground control when

ready to taxi.

5. Normally, pilots need not inform ground control that they have received IFR clearance on clearance

delivery frequency. Certain locations may, however, require that the pilot inform ground control of a portion of

the routing or that the IFR clearance has been received.

6. If a pilot cannot establish contact on clearance delivery frequency or has not received an IFR clearance

before ready to taxi, the pilot should contact ground control and inform the controller accordingly.

b. Locations where these procedures are in effect are indicated in the Chart Supplement.

5−2−2. Automated Pre−Departure Clearance Procedures

a. Many airports in the National Airspace System are equipped with the Terminal Data Link System (TDLS)

that includes the Pre−Departure Clearance (PDC) and Controller Pilot Data Link Communication–Departure

Clearance (CPDLC-DCL) functions. Both the PDC and CPDLC-DCL functions automate the Clearance

Delivery operations in the ATCT for participating users. Both functions display IFR clearances from the ARTCC

to the ATCT. The Clearance Delivery controller in the ATCT can append local departure information and transmit

the clearance via data link to participating airline/service provider computers for PDC. The airline/service

provider will then deliver the clearance via the Aircraft Communications Addressing and Reporting System

(ACARS) or a similar data link system, or for non-data link equipped aircraft, via a printer located at the departure

gate. For CPDLC-DCL, the departure clearance is uplinked from the ATCT via the Future Air Navigation System

(FANS) to the aircraft avionics and requires a response from the flight crew. Both PDC and CPDLC-DCL reduce

frequency congestion, controller workload, and are intended to mitigate delivery/read back errors.

b. Both services are available only to participating aircraft that have subscribed to the service through an

approved service provider.

c. In all situations, the pilot is encouraged to contact clearance delivery if a question or concern exists

regarding an automated clearance. Due to technical reasons, the following limitations/differences exist between

the two services:

1. PDC

(a) Aircraft filing multiple flight plans are limited to one PDC clearance per departure airport within an

18−hour period. Additional clearances will be delivered verbally.

(b) If the clearance is revised or modified prior to delivery, it will be rejected from PDC and the clearance

will need to be delivered verbally.

(c) No acknowledgment of receipt or read back is required for a PDC.

Departure Procedures 5−2−1

AIM 2/20/25

2. CPDLC−DCL

(a) No limitation to the number of clearances received.

(b) Allows delivery of revised flight data, including revised departure clearances.

(c) A response from the flight crew is required.

(d) Requires a logon to the FAA National Single Data Authority − KUSA − utilizing the ATC FANS

application.

(e) To be eligible, operators must have received CPDLC/FANS authorization from the responsible civil

aviation authority, and file appropriate equipment information in ICAO field 10a and in the ICAO field 18 DAT

(Other Data Applications) of the flight plan.

5−2−3. IFR Clearances Off Uncontrolled Airports

a. Pilots departing on an IFR flight plan should consult the Chart Supplement to determine the frequency or

telephone number to use to contact clearance delivery. On initial contact, pilots should advise that the flight is

IFR and state the departure and destination airports.

b. Air traffic facilities providing clearance delivery services via telephone will have their telephone number

published in the Chart Supplement of that airport’s entry. This same section may also contain a telephone number

to use for cancellation of an IFR flight plan after landing.

c. Except in Alaska, pilots of MEDEV AC flights may obtain a clearance by calling 1−877−543−4733.

5−2−4. Taxi Clearance

Pilots on IFR flight plans should communicate with the control tower on the appropriate ground control or

clearance delivery frequency prior to starting engines, to receive engine start time, taxi, and/or clearance

information.

5−2−5. Line Up and Wait (LUAW)

a. Line up and wait is an air traffic control (ATC) procedure designed to position an aircraft onto the runway

for an imminent departure. The ATC instruction “LINE UP AND WAIT” is used to instruct a pilot to taxi onto

the assigned departure runway, align the aircraft with the correct departure direction and await for further ATC

instructions. LUAW is not an authorization to takeoff.

EXAMPLE−

Tower: “N234AR Runway 24L, line up and wait.”

NOTE−

Previous reviews of air traffic events, involving LUAW instructions, revealed that a significant number of pilots read back

LUAW instructions correctly and departed without a takeoff clearance. LUAW instructions are not to be confused with a

departure clearance; the outcome could be catastrophic, especially during intersecting runway operations.

b. In instances where the pilot has been instructed to LUAW and has been advised of a reason/condition (wake

turbulence, traffic on an intersecting runway, etc.) or the reason/condition is clearly visible (another aircraft that

has landed on or is taking off on the same runway), and the reason/condition is satisfied, the pilot should expect

an imminent takeoff clearance, unless advised of a delay. If you are uncertain about any ATC instruction or

clearance, contact ATC immediately.

c. If a takeoff clearance is not received within a reasonable amount of time after instructed to LUAW, ATC

should be contacted.

EXAMPLE−

Aircraft: Cessna 234AR holding in position Runway 24L.

Aircraft: Cessna 234AR holding in position Runway 24L at Bravo.

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2/20/25 AIM

NOTE−

F AA analysis of accidents and incidents involving aircraft holding in position indicate that two minutes or more elapsed

between the time the instruction was issued to line up and wait and the resulting event (for example, land −over or

go−around). Pilots should consider the length of time that they have been holding in position whenever they HAVE NOT been

advised of any expected delay to determine when it is appropriate to query the controller .

REFERENCE−

Advisory Circulars 91−73A, Part 91 and Part 135 Single−Pilot Procedures during Taxi Operations, and 120−74A, Parts 91, 121, 125, and 135 Flightcrew

Procedures during Taxi Operations.

d. Situational awareness during line up and wait operations is enhanced by monitoring ATC

instructions/clearances issued to other aircraft. Pilots should listen carefully if another aircraft is on frequency

that has a similar call sign and pay close attention to communications between ATC and other aircraft. If you are

uncertain of an ATC instruction or clearance, query ATC immediately. Care should be taken to not inadvertently

execute a clearance/instruction for another aircraft.

e. Pilots should be especially vigilant when conducting LUAW operations at night, when intersecting runway

operations are being conducted, or during reduced visibility conditions. Pilots should scan the full length of the

runway and look for aircraft crossing the runway, on final approach, or landing roll (including intersecting

runways) prior to and while taxiing onto the runway. ATC should be contacted anytime there is a concern about

a potential conflict or clarity is needed with assigned instructions.

NOTE−

Pilots are reminded of the importance of maintaining situational awareness during LUAW operations with

intersecting/crossing runways. Ensure a takeoff clearance has been received before beginning a takeoff roll.

f. When two or more runways are active, aircraft may be instructed to “LINE UP AND WAIT” on two or more

runways. When multiple runway operations are being conducted, it is important to listen closely for your call

sign and runway. Be alert for similar sounding call signs and acknowledge all instructions with your call sign.

When you are holding in position and are not sure if the takeoff clearance was for you, ask ATC before you begin

takeoff roll. ATC prefers that you confirm a takeoff clearance rather than mistake another aircraft’s clearance

for your own.

g. When ATC issues intersection “line up and wait” and takeoff clearances, the intersection designator will

be used. If ATC omits the intersection designator, call ATC for clarification.

EXAMPLE−

Aircraft: “Cherokee 234AR, Runway 24L at November 4, line up and wait.”

h. If landing traffic is a factor during line up and wait operations, ATC will inform the aircraft in position of

the closest traffic within 6 flying miles requesting a full−stop, touch−and−go, stop−and−go, or an unrestricted

low approach to the same runway. Pilots should take care to note the position of landing traffic. ATC will also

advise the landing traffic when an aircraft is authorized to “line up and wait” on the same runway.

EXAMPLE−

Tower: “Cessna 234AR, Runway 24L, line up and wait. Traffic a Boeing 737, six mile final.”

Tower: “Delta 1011, continue, traffic a Cessna 210 holding in position Runway 24L.”

NOTE−

ATC will normally withhold landing clearance to arrival aircraft when another aircraft is in position and holding on the

runway.

i. Never land on a runway that is occupied by another aircraft, even if a landing clearance was issued. Do not

hesitate to ask the controller about the traffic on the runway and be prepared to execute a go−around.

NOTE−

Always clarify any misunderstanding or confusion concerning ATC instructions or clearances. ATC should be advised

immediately if there is any uncertainty about the ability to comply with any of their instructions.

Departure Procedures 5−2−3

AIM 2/20/25

5−2−6. Abbreviated IFR Departure Clearance (Cleared. . .as Filed) Procedures

a. ATC facilities will issue an abbreviated IFR departure clearance based on the ROUTE of flight filed in the

IFR flight plan, provided the filed route can be approved with little or no revision. These abbreviated clearance

procedures are based on the following conditions:

1. The aircraft is on the ground or it has departed visual flight rules (VFR) and the pilot is requesting IFR

clearance while airborne.

2. That a pilot will not accept an abbreviated clearance if the route or destination of a flight plan filed with

ATC has been changed by the pilot or the company or the operations officer before departure.

3. That it is the responsibility of the company or operations office to inform the pilot when they make a

change to the filed flight plan.

4. That it is the responsibility of the pilot to inform ATC in the initial call-up (for clearance) when the filed

flight plan has been either:

(a) Amended, or

(b) Canceled and replaced with a new filed flight plan.

NOTE−

The facility issuing a clearance may not have received the revised route or the revised flight plan by the time a pilot requests

clearance.

b. Controllers will issue a detailed clearance when they know that the original filed flight plan has been

changed or when the pilot requests a full route clearance.

c. The clearance as issued will include the destination airport filed in the flight plan.

d. ATC procedures now require the controller to state the DP name, the current number and the DP transition

name after the phrase “Cleared to (destination) airport” and prior to the phrase, “then as filed,” for ALL departure

clearances when the DP or DP transition is to be flown. The procedures apply whether or not the DP is filed in

the flight plan.

e. STARs, when filed in a flight plan, are considered a part of the filed route of flight and will not normally

be stated in an initial departure clearance. If the ARTCC’s jurisdictional airspace includes both the departure

airport and the fix where a STAR or STAR transition begins, the STAR name, the current number and the STAR

transition name MAY be stated in the initial clearance.

f. “Cleared to (destination) airport as filed” does NOT include the en route altitude filed in a flight plan. An

en route altitude will be stated in the clearance or the pilot will be advised to expect an assigned or filed altitude

within a given time frame or at a certain point after departure. This may be done verbally in the departure

instructions or stated in the DP.

g. In both radar and nonradar environments, the controller will state “Cleared to (destination) airport as filed”

or:

1. If a DP or DP transition is to be flown, specify the DP name, the current DP number, the DP transition

name, the assigned altitude/flight level, and any additional instructions (departure control frequency, beacon

code assignment, etc.) necessary to clear a departing aircraft via the DP or DP transition and the route filed.

EXAMPLE−

National Seven Twenty cleared to Miami Airport Intercontinental one departure, Lake Charles transition then as filed,

maintain Flight Level two seven zero.

2. When there is no DP or when the pilot cannot accept a DP , the controller will specify the assigned altitude

or flight level, and any additional instructions necessary to clear a departing aircraft via an appropriate departure

routing and the route filed.

NOTE−

A detailed departure route description or a radar vector may be used to achieve the desired departure routing.

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2/20/25 AIM

3. If it is necessary to make a minor revision to the filed route, the controller will specify the assigned DP

or DP transition (or departure routing), the revision to the filed route, the assigned altitude or flight level and any

additional instructions necessary to clear a departing aircraft.

EXAMPLE−

Jet Star One Four Two Four cleared to Atlanta Airport, South Boston two departure then as filed except change route to read

South Boston Victor 20 Greensboro, maintain one seven thousand.

4. Additionally, in a nonradar environment, the controller will specify one or more fixes, as necessary, to

identify the initial route of flight.

EXAMPLE−

Cessna Three One Six Zero Foxtrot cleared to Charlotte Airport as filed via Brooke, maintain seven thousand.

h. To ensure success of the program, pilots should:

1. Avoid making changes to a filed flight plan just prior to departure.

2. State the following information in the initial call-up to the facility when no change has been made to the

filed flight plan: Aircraft call sign, location, type operation (IFR) and the name of the airport (or fix) to which

you expect clearance.

EXAMPLE−

“Washington clearance delivery (or ground control if appropriate) American Seventy Six at gate one, IFR Los Angeles.”

3. If the flight plan has been changed, state the change and request a full route clearance.

EXAMPLE−

“Washington clearance delivery, American Seventy Six at gate one. IFR San Francisco. My flight plan route has been

amended (or destination changed). Request full route clearance.”

4. Request verification or clarification from ATC if ANY portion of the clearance is not clearly understood.

5. When requesting clearance for the IFR portion of a VFR/IFR flight, request such clearance prior to the

fix where IFR operation is proposed to commence in sufficient time to avoid delay. Use the following

phraseology:

EXAMPLE−

“Los Angeles center, Apache Six One Papa, VFR estimating Paso Robles VOR at three two, one thousand five hundred,

request IFR to Bakersfield.”

5−2−7. Departure Restrictions, Clearance Void Times, Hold for Release, and Release Times

a. ATC may assign departure restrictions, clearance void times, hold for release, and release times, when

necessary, to separate departures from other traffic or to restrict or regulate the departure flow. Departures from

an airport without an operating control tower must be issued either a departure release (along with a release time

and/or void time if applicable), or a hold for release.

REFERENCE−

F AA Order JO 7110.65, Para 4−3−4, Departure Release, Hold for Release, Release Times, Departure Restrictions, and Clearance Void Times.

1. Clearance Void Times. A pilot may receive a clearance, when operating from an airport without a

control tower, which contains a provision for the clearance to be void if not airborne by a specific time. A pilot

who does not depart prior to the clearance void time must advise ATC as soon as possible of their intentions. ATC

will normally advise the pilot of the time allotted to notify ATC that the aircraft did not depart prior to the

clearance void time. This time cannot exceed 30 minutes. Failure of an aircraft to contact ATC within 30 minutes

after the clearance void time will result in the aircraft being considered overdue and search and rescue procedures

initiated.

NOTE−

1. Other IFR traffic for the airport where the clearance is issued is suspended until the aircraft has contacted ATC or until

30 minutes after the clearance void time or 30 minutes after the clearance release time if no clearance void time is issued.

2. If the clearance void time expires, it does not cancel the departure clearance or IFR flight plan. It withdraws the pilot’ s

authority to depart IFR until a new departure release/release time has been issued by ATC and is acknowledged by the pilot.

Departure Procedures 5−2−5

AIM 2/20/25

3. Pilots who depart at or after their clearance void time are not afforded IFR separation and may be in violation of 14 CFR

section 91.173 which requires that pilots receive an appropriate ATC clearance before operating IFR in controlled airspace.

4. Pilots who choose to depart VFR after their clearance void time has expired should not depart using the previously

assigned IFR transponder code.

EXAMPLE−

Clearance void if not off by (clearance void time) and, if required, if not off by (clearance void time) advise (facility) not later

than (time) of intentions.

2. Hold for Release. ATC may issue “hold for release” instructions in a clearance to delay an aircraft’s

departure for traffic management reasons (i.e., weather, traffic volume, etc.). When ATC states in the clearance,

“hold for release,” the pilot may not depart utilizing that IFR clearance until a release time or additional

instructions are issued by ATC. In addition, ATC will include departure delay information in conjunction with

“hold for release” instructions. The ATC instruction, “hold for release,” applies to the IFR clearance and does

not prevent the pilot from departing under VFR. However, prior to takeoff the pilot should cancel the IFR flight

plan and operate the transponder/ADS−B on the appropriate VFR code. An IFR clearance may not be available

after departure.

EXAMPLE−

(Aircraft identification) cleared to (destination) airport as filed, maintain (altitude), and, if required (additional instructions

or information), hold for release, expect (time in hours and/or minutes) departure delay.

3. Release Times. A “release time” is a departure restriction issued to a pilot by ATC, specifying the

earliest time an aircraft may depart. ATC will use “release times” in conjunction with traffic management

procedures and/or to separate a departing aircraft from other traffic.

EXAMPLE−

(Aircraft identification) released for departure at (time in hours and/or minutes).

4. Expect Departure Clearance Time (EDCT). The EDCT is the runway release time assigned to an

aircraft included in traffic management programs. Aircraft are expected to depart no earlier than 5 minutes

before, and no later than 5 minutes after the EDCT.

b. If practical, pilots departing uncontrolled airports should obtain IFR clearances prior to becoming airborne

when two-way communications with the controlling ATC facility is available.

5−2−8. Departure Control

a. Departure Control is an approach control function responsible for ensuring separation between departures.

So as to expedite the handling of departures, Departure Control may suggest a takeoff direction other than that

which may normally have been used under VFR handling. Many times it is preferred to offer the pilot a runway

that will require the fewest turns after takeoff to place the pilot on course or selected departure route as quickly

as possible. At many locations particular attention is paid to the use of preferential runways for local noise

abatement programs, and route departures away from congested areas.

b. Departure Control utilizing radar will normally clear aircraft out of the terminal area using vectors, a

diverse vector area (DV A), or published DPs.

1. When a departure is to be vectored immediately following takeoff using vectors, a DV A, or published

DPs that begins with an ATC assigned heading off the ground, the pilot will be advised prior to takeoff of the

initial heading to be flown but may not be advised of the purpose of the heading. When ATC assigns an initial

heading with the takeoff clearance that will take the aircraft off an assigned procedure (for example, an RNA V

SID with a published lateral path to a waypoint and crossing restrictions from the departure end of runway), the

controller will assign an altitude to maintain with the initial heading and, if necessary, a speed to maintain.

2. At some airports when a departure will fly an RNA V SID that begins at the runway, ATC may advise

aircraft of the initial fix/waypoint on the RNA V route. The purpose of the advisory is to remind pilots to verify

the correct procedure is programmed in the FMS before takeoff. Pilots must immediately advise ATC if a

different RNA V SID is entered in the aircraft’s FMC. When this advisory is absent, pilots are still required to

fly the assigned SID as published.

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2/20/25 AIM

EXAMPLE−

Delta 345 RNAV to MP ASS, Runway26L, cleared for takeoff.

NOTE−

1. The SID transition is not restated as it is contained in the ATC clearance.

2. Aircraft cleared via RNAV SIDs designed to begin with a vector to the initial waypoint are assigned a heading before

departure.

3. Pilots operating in a radar environment are expected to associate departure headings or an RNA V

departure advisory with vectors or the flight path to their planned route or flight. When given a vector taking the

aircraft off a previously assigned nonradar route, the pilot will be advised briefly what the vector is to achieve.

Thereafter, radar service will be provided until the aircraft has been reestablished “on-course” using an

appropriate navigation aid and the pilot has been advised of the aircraft’s position or a handoff is made to another

radar controller with further surveillance capabilities.

c. Controllers will inform pilots of the departure control frequencies and, if appropriate, the transponder code

before takeoff. Pilots must ensure their transponder/ADS−B is adjusted to the “on” or normal operating position

as soon as practical and remain on during all operations unless otherwise requested to change to “standby” by

ATC. Pilots should not change to the departure control frequency until requested. Controllers may omit the

departure control frequency if a DP has or will be assigned and the departure control frequency is published on

the DP.

5−2−9. Instrument Departure Procedures (DP) − Obstacle Departure Procedures (ODP),

Standard Instrument Departures (SID), and Diverse Vector Areas (DVA)

a. Instrument departure procedures are preplanned instrument flight rule (IFR) procedures which provide

obstruction clearance from the terminal area to the appropriate en route structure. There are two types of DPs,

Obstacle Departure Procedures (ODP), printed either textually or graphically, and Standard Instrument

Departures (SID), always printed graphically. All DPs, either textual or graphic may be designed using either

conventional or RNA V criteria. RNA V procedures will have RNA V printed in the title; for example, SHEAD

TWO DEPARTURE (RNA V). ODPs provide obstruction clearance via the least onerous route from the terminal

area to the appropriate en route structure. ODPs are recommended for obstruction clearance and may be flown

without ATC clearance unless an alternate departure procedure (SID or radar vector) has been specifically

assigned by ATC. Graphic ODPs will have (OBSTACLE) printed in the procedure title; for example, GEYSR

THREE DEPARTURE (OBSTACLE), or, CROWN ONE DEPARTURE (RNA V) (OBSTACLE). Standard

Instrument Departures are air traffic control (ATC) procedures printed for pilot/controller use in graphic form

to provide obstruction clearance and a transition from the terminal area to the appropriate en route structure. SIDs

are primarily designed for system enhancement and to reduce pilot/controller workload. ATC clearance must be

received prior to flying a SID. All DPs provide the pilot with a way to depart the airport and transition to the en

route structure safely.

b. A Diverse Vector Area (DV A) is an area in which ATC may provide random radar vectors during an

uninterrupted climb from the departure runway until above the MV A/MIA, established in accordance with the

TERPS criteria for diverse departures. The DV A provides obstacle and terrain avoidance in lieu of taking off

from the runway under IFR using an ODP or SID.

c. Pilots operating under 14 CFR part 91 are strongly encouraged to file and fly a DP at night, during marginal

Visual Meteorological Conditions (VMC) and Instrument Meteorological Conditions (IMC), when one is

available. The following paragraphs will provide an overview of the DP program, why DPs are developed, what

criteria are used, where to find them, how they are to be flown, and finally pilot and ATC responsibilities.

d. Why are DPs necessary? The primary reason is to provide obstacle clearance protection information to

pilots. A secondary reason, at busier airports, is to increase efficiency and reduce communications and departure

delays through the use of SIDs. When an instrument approach is initially developed for an airport, the need for

DPs is assessed. The procedure designer conducts an obstacle analysis to support departure operations. If an

Departure Procedures 5−2−7

AIM 2/20/253/15/077110.65R CHG 2AIM 8/7/25

aircraft may turn in any direction from a runway within the limits of the assessment area (see paragraph 5−2−9e3)

and remain clear of obstacles, that runway passes what is called a diverse departure assessment and no ODP will

be published. A SID may be published if needed for air traffic control purposes. However, if an obstacle

penetrates what is called the 40:1 obstacle identification surface, then the procedure designer chooses whether

to:

1. Establish a steeper than normal climb gradient; or

2. Establish a steeper than normal climb gradient with an alternative that increases takeoff minima to allow

the pilot to visually remain clear of the obstacle(s); or

3. Design and publish a specific departure route; or

4. A combination or all of the above.

e. What criteria is used to provide obstruction clearance during departure?

1. Unless specified otherwise, required obstacle clearance for all departures, including diverse, is based on

the pilot crossing the departure end of the runway at least 35 feet above the departure end of runway elevation,

climbing to 400 feet above the departure end of runway elevation before making the initial turn, and maintaining

a minimum climb gradient of 200 feet per nautical mile (FPNM), unless required to level off by a crossing

restriction, until the minimum IFR altitude. A greater climb gradient may be specified in the DP to clear obstacles

or to achieve an ATC crossing restriction. If an initial turn higher than 400 feet above the departure end of runway

elevation is specified in the DP, the turn should be commenced at the higher altitude. If a turn is specified at a

fix, the turn must be made at that fix. Fixes may have minimum and/or maximum crossing altitudes that must

be adhered to prior to passing the fix. In rare instances, obstacles that exist on the extended runway centerline

may make an “early turn” more desirable than proceeding straight ahead. In these cases, the published departure

instructions will include the language “turn left(right) as soon as practicable.” These departures will also include

a ceiling and visibility minimum of at least 300 and 1. Pilots encountering one of these DPs should preplan the

climb out to gain altitude and begin the turn as quickly as possible within the bounds of safe operating practices

and operating limitations. This type of departure procedure is being phased out.

NOTE−

“Practical” or “feasible” may exist in some existing departure text instead of “practicable.”

2. ODPs, SIDs, and DV As assume normal aircraft performance, and that all engines are operating.

Development of contingency procedures, required to cover the case of an engine failure or other emergency in

flight that may occur after liftoff, is the responsibility of the operator. (More detailed information on this subject

is available in Advisory Circular AC 120−91, Airport Obstacle Analysis, and in the “Departure Procedures”

section of chapter 2 in the Instrument Procedures Handbook, FAA−H−8083−16.)

3. The 40:1 obstacle identification surface (OIS) begins at the departure end of runway (DER) and slopes

upward at 152 FPNM until reaching the minimum IFR altitude or entering the en route structure. This assessment

area is limited to 25 NM from the airport in nonmountainous areas and 46 NM in designated mountainous areas.

Beyond this distance, the pilot is responsible for obstacle clearance if not operating on a published route, if below

(having not reached) the MEA or MOCA of a published route, or an A TC assigned altitude. See FIG 5−2−1. (Ref

14 CFR 91.177 for further information on en route altitudes.)

NOTE−

ODPs are normally designed to terminate within these distance limitations, however, some ODPs will contain routes that

may exceed 25/46 NM; these routes will ensure obstacle protection until reaching the end of the ODP .

5−2−8 Departure Procedures

AIM2/20/258/7/25 AIM

FIG 5−2−1

Diverse Departure Obstacle Assessment to 25/46 NM

4. Takeoff Obstacles. Takeoff Obstacles Notes in the “Takeoff Minimums and (OBSTACLE) Departure

Procedures” section of the Terminal Procedures Publication (TPP) identifies obstacle(s) that penetrate the 40:1

OCS. The obstacle notes alert the pilot to the height and location of the obstacles relative to the DER so they can

be avoided. This can be accomplished in a variety of ways: the pilot may be able to see and avoid the obstruction;

early liftoff/climb performance may allow the aircraft to cross well above the obstacle(s); or if the obstacle(s)

cannot be visually acquired during departure, the takeoff should be delayed or another runway selected for the

IFR departure.

(a) Takeoff obstacles will be published as low, close−in and/or takeoff minimums obstacle notes.

(1) Low, close−in obstacles require a higher than standard climb gradient (within 1 NM or less from

DER) to an altitude of 200 feet or less above DER elevation and do not require increased takeoff minimums.

(2) Takeoff minimums obstacles require a higher than standard climb gradient (within 2.6 NM from

DER) to an altitude greater than 200 feet above the DER elevation and require increased takeoff minimums.

These obstacles are published with higher than standard ceiling and visibility takeoff minimums and are

published in the same obstacle listing.

(b) Obstacle notes are not required to be charted on SIDs. When a pilot is assigned a SID for departure

refer to the airport entry in the TPP or the graphic ODP to obtain information on the takeoff obstacles.

(c) The FAA redefined the initial climb area criteria that are used to evaluate and identify the obstacles

that penetrate the 40:1 OCS. The takeoff obstacle notes are published in a different manner and an additional

minimums option is added for the departure. To ensure the pilot knows which evaluation was accomplished, the

charting will be different by bolding certain headers and runway information. Until the FAA can amend all

departures the legacy obstacle notes will still be published.

(1) For textual departures, the headers Takeoff Minimums, Departure Procedures, and Takeoff

Obstacle Notes will be bolded and underlined. The specific runway entries under each header will continue to

be bolded.

(2) For graphic departure procedures, the headers Takeoff Minimums and Takeoff Obstacle Notes will

be bolded and continue to be underlined. The specific runway entries for these headers will be bolded. In the

Departure Route Description section of the graphic departure, the heading will be bolded and underlined and the

runway information will just be bolded.

(3) Legacy takeoff obstacle notes combine low, close−in and takeoff obstacles for each runway.

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(4) New takeoff obstacle notes separate low, close−in and takeoff minimums obstacle notes. There is

also a DER crossing altitude included in the notes section, providing the pilot with a DER crossing height that

clears all obstacles that penetrate the 40:1 OCS.

(5) The obstacles are described with an inner limit from the DER, using the word “beginning,”

expressed in 1/4 SM increments rounded down and an outer limit, using the words “extending to” expressed in

1/4 SM increments rounded up. They will also be described in relation to the extended runway centerline as “left,

right, or crossing.” Crossing means they are within 100ft of the centerline. Left or right means they are greater

than 100 ft from centerline. Both an MSL altitude and height above DER elevation will be provided for the

obstacle that penetrates the 40:1 OCS the most. This allows the pilot to determine when the reported weather

conditions are adequate to see and avoid the low, close−in obstacle(s) if aircraft performance does not permit the

aircraft to climb over them. It also allows the pilot to correlate the position of the obstacles and the MSL elevation

and height above DER for the controlling obstacle for the published higher than standard takeoff minimums.

(6) A DER crossing height using standard ceiling/visibility is provided as a new takeoff minimums

option for pilots in addition to the current options (higher than standard ceiling/visibility or standard

ceiling/visibility with a higher than standard climb gradient, or a reduced takeoff runway length with a standard

climb gradient and standard ceiling/visibility).

EXAMPLE−

Legacy takeoff minimums and obstacle notes

TAKEOFF MINIMUMS:

Rwy12 L/R, 400−2 1/2 or std. w/min. climb of 261’ per NM to 500.

TAKEOFF OBSTACLE NOTES:

Rwy 14, trees 2011’ from DER, 29’ left of centerline, 100’ AGL/3829’ MSL.

Rwy 32, trees 1009’ from DER, 697’ left of centerline, 100’ AGL/3839’ MSL.

Tower 4448’ from DER, 1036’ left of centerline, 165’ AGL/3886’ MSL.

EXAMPLE−

New takeoff minimums and obstacle notes

TAKEOFF MINIMUMS:

Rwy12 L/R: 400−2 1/2 or std. w/min. climb of 261’ per NM to 500 or standard and crossing DER 66’ above DER Elev clears

takeoff minimums obstacles.

TAKEOFF OBSTACLE NOTES:

Rwy 12L LOW, CLOSE−IN OBSTACLES: trees beginning 600’ from DER, extending to 1/2 SM, crossing centerline, up

to 156’ MSL, 86’ above DER, crossing DER 49’ above DER Elev clears low, close−in obstacles.

Rwy 12L TAKEOFF MINIMUMS OBSTACLES: buildings, crane, tower beginning 1 1/2 SM from DER, extending to 1

3/4 SM, left, right, and crossing centerline, up to 373’ MSL, 284’ above DER, crossing DER at 66’ above DER Elev clears

takeoff minimums obstacles.

Rwy 12R LOW, CLOSE−IN OBSTACLES: obstacles 35’ and below.

Rwy 12R TAKEOFF MINIMUMS OBSTACLES: buildings, crane, tower beginning 1 1/2 SM from DER, extending to 1

3/4 SM, left, right, and crossing centerline, up to 373’ MSL, 284’ above DER, crossing DER at 66’ above DER Elev clears

takeoff minimums obstacles.

Rwy 30L/R LOW, CLOSE−IN OBSTACLES: obstacles 35’ and below.

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(d) Compliance with 14 CFR part 121 or 135 one−engine −inoperative (OEI) departure performance

requirements, or similar ICAO/State rules, cannot be assured by the sole use of takeoff obstacle note data as

published in the TPP. Operators conducting these operations should refer to precise data sources (GIS database,

etc.) specifically intended for OEI departure planning (see AC 120−91).

5. Climb gradients greater than 200 FPNM are specified when required to support procedure design

constraints, obstacle clearance, and/or airspace restrictions. Compliance with a climb gradient for these purposes

is mandatory when the procedure is part of the ATC clearance, unless increased takeoff minimums are provided

and weather conditions allow compliance with these minimums.

NOTE−

Climb gradients for ATC purposes are being phased out on SIDs.

EXAMPLE−

“Cross ALPHA intersection at or below 4000; maintain 6000.” The pilot climbs at least 200 FPNM to 6000. If 4000 is

reached before ALPHA, the pilot levels off at 4000 until passing ALPHA; then immediately resumes at least 200 FPNM

climb.

EXAMPLE−

“TAKEOFF MINIMUMS: RWY 27, Standard with a minimum climb of 280’ per NM to 2500.” A climb of at least 280 FPNM

is required to 2500 and is mandatory when the departure procedure is included in the ATC clearance.

NOTE−

Some SIDs still retain labeled “ATC” climb gradients published or have climb gradients that are established to meet a

published altitude restriction that is not required for obstacle clearance or procedure design criteria. These procedures will

be revised in the course of the normal procedure amendment process.

6. Climb gradients may be specified only to an altitude/fix, above which the normal gradient applies. An

ATC−required altitude restriction published at a fix, will not have an associated climb gradient published with

that restriction. Pilots are expected to determine if crossing altitudes can be met, based on the performance

capability of the aircraft they are operating.

EXAMPLE−

“Minimum climb 340 FPNM to ALPHA.” The pilot climbs at least 340 FPNM to ALPHA, then at least 200 FPNM to MIA.

7. A Visual Climb Over Airport (VCOA) procedure is a departure option for an IFR aircraft, operating in

visual meteorological conditions equal to or greater than the specified visibility and ceiling, to visually conduct

climbing turns over the airport to the published “at or above” altitude. At this point, the pilot may proceed in

instrument meteorological conditions to the first en route fix using a diverse departure, or to proceed via a

published routing to a fix from where the aircraft may join the IFR en route structure, while maintaining a climb

gradient of at least 200 feet per nautical mile. VCOA procedures are developed to avoid obstacles greater than

3 statute miles from the departure end of the runway as an alternative to complying with climb gradients greater

than 200 feet per nautical mile. Pilots are responsible to advise ATC as early as possible of the intent to fly the

VCOA option prior to departure. Pilots are expected to remain within the distance prescribed in the published

visibility minimums during the climb over the airport until reaching the “at or above” altitude for the VCOA

procedure. If no additional routing is published, then the pilot may proceed in accordance with their IFR

clearance. If additional routing is published after the “at−or−above” altitude, the pilot must comply with the route

to a fix that may include a climb−in−holding pattern to reach the MEA/MIA for the en route portion of their IFR

flight. These textual procedures are published in the Takeoff Minimums and (Obstacle) Departure Procedures

section of the TPP and/or appear as an option on a Graphic ODP.

EXAMPLE−

TAKEOFF MINIMUMS: Rwy 32, standard with minimum climb of 410’ per NM to 3000’ or 1100−3 for VCOA.

VCOA: Rwy 32, when executing VCOA, notify ATC prior to departure. Climb in visual conditions to cross Broken Bow

Muni/Keith Glaze Field at or above 3500’ before proceeding on course.

f. Obstacle Clearance Responsibilities. DPs are designed so that the pilot’s adherence to the procedure’s

lateral path and vertical climb requirements will ensure obstacle protection.

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1. Obstacle clearance responsibility rests with the pilot when he/she chooses to depart IFR under 14 CFR

part 91 and has not filed or been cleared for an ODP or an ATC−assigned SID or assigned headings for a DV A

from the departure runway. Standard takeoff minimums are one statute mile for aircraft having two engines or

less and one−half statute mile for aircraft having more than two engines. Higher than standard ceiling and

visibility minimums will allow visual avoidance of the obstacles during the initial climb at the standard climb

gradient.

2. When cleared to depart IFR using the ODP, SID, VCOA, or assigned headings for DV A, pilots must

reference the published takeoff minimums and takeoff obstacle notes.

(a) Since the presence of low, close−in obstacles do not require publishing increased takeoff minimums

the pilot should consider, if necessary to see and avoid these obstacles, the weather at time of takeoff. Based on

the position of low, close−in obstacles, weather no less than 300 ft and 1 NM may be necessary to visually avoid

obstacles.

(b) Takeoff minimums obstacles are especially critical to aircraft that do not lift off until close to the

departure end of the runway or which climb at the minimum rate. When departing IFR using the higher than

standard takeoff minimums option, pilots are responsible for visually avoiding takeoff minimums obstacles.

Pilots should also consider drift following lift −off to ensure sufficient clearance from these obstacles. The

segment of the procedure that requires the pilot to see and avoid obstacles ends when the aircraft is beyond or

above the ceiling and visibility published to avoid these obstacles.

3. When departing using the VCOA, obstacle avoidance is not guaranteed if the pilot maneuvers farther

from the airport than the published visibility minimum for the VCOA prior to reaching the published VCOA

altitude. Pilots are responsible for maintaining clearance from low, close−in obstacles.

4. When departing using a DV A, pilots are responsible for maintaining clearance from low, close −in

obstacles. DV As may also require a higher than standard climb gradient. Standard takeoff minimums apply when

departing a runway under IFR when using the DV A. The existence of a DV A will be noted in the Takeoff

Minimums and (Obstacle) Departure Procedure section of the TPP.

EXAMPLE−

DIVERSE VECTOR AREA (RADAR VECTORS) AMDT 1 14289 (F AA)

Rwy 6R, headings as assigned by ATC; requires minimum climb of 290’ per NM to 400.

Rwys 6L, 7L, 7R, 24R, 25R, headings as assigned by ATC.

5. In all cases, continued obstacle clearance is based on having climbed a minimum of 200 feet per nautical

mile to the specified point and then continuing to climb at least 200 feet per nautical mile during the departure

until reaching the minimum en route altitude, unless higher than standard climb gradient is published. When a

higher than standard climb gradient is published and used, that climb gradient is maintained, until reaching the

climb gradient termination altitude, after which the standard 200 feet per nautical mile is maintained until

reaching the minimum en route altitude.

NOTE−

As is always the case, when used by the controller during departure, the term “radar contact” should not be interpreted as

relieving pilots of their responsibility to maintain appropriate terrain and obstruction clearance, which may include flying

the obstacle DP .

g. Where are DPs located? DPs and DV As will be listed by airport in the IFR Takeoff Minimums and

(Obstacle) Departure Procedures Section, Section L, of the TPP. If the DP is textual, it will be described in TPP

Section L. SIDs and complex ODPs will be published graphically and named. The name will be listed by airport

name and runway in Section L. Graphic ODPs will also have the term “(OBSTACLE)” printed in the charted

procedure title, differentiating them from SIDs.

1. An ODP that has been developed solely for obstacle avoidance will be indicated with the symbol “T”

on appropriate Instrument Approach Procedure (IAP) charts and DP charts for that airport. The “T” symbol will

continue to refer users to TPP Section C. In the case of a graphic ODP, the TPP Section C will only contain the

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AIM2/20/258/7/25 AIM

name of the ODP. Since there may be both a textual and a graphic DP, Section C should still be checked for

additional information. The nonstandard takeoff minimums and minimum climb gradients found in TPP Section

C also apply to charted DPs and radar vector departures unless different minimums are specified on the charted

DP. Takeoff minimums and departure procedures apply to all runways unless otherwise specified. New graphic

DPs will have all the information printed on the graphic depiction. As a general rule, ATC will only assign an

ODP from a non−towered airport when compliance with the ODP is necessary for aircraft to aircraft separation.

Pilots may use the ODP to help ensure separation from terrain and obstacles.

h. Responsibilities

1. Each pilot, prior to departing an airport on an IFR flight should:

(a) Consider the type of terrain and other obstacles on or in the vicinity of the departure airport;

(b) Determine whether an ODP is available;

(c) Determine if obstacle avoidance can be maintained visually or if the ODP should be flown; and

(d) Consider the effect of degraded climb performance and the actions to take in the event of an engine

loss during the departure. Pilots should notify ATC as soon as possible of reduced climb capability in that

circumstance.

NOTE−

Guidance concerning contingency procedures that address an engine failure on takeoff after V 1 speed on a large or

turbine−powered transport category airplane may be found in AC 120−91, Airport Obstacle Analysis.

(e) Determine if a DV A is published and whether the aircraft is capable of meeting the published climb

gradient. Advise ATC when requesting the IFR clearance, or as soon as possible, if unable to meet the DV A climb

gradient.

(f) Check for Takeoff Obstacle Notes published in the TPP for the takeoff runway.

2. Pilots should not exceed a published speed restriction associated with a SID waypoint until passing that

waypoint.

3. After an aircraft is established on a SID and subsequently vectored or cleared to deviate off of the SID

or SID transition, pilots must consider the SID canceled, unless the controller adds “expect to resume SID;” pilots

should then be prepared to rejoin the SID at a subsequent fix or procedure leg. If the SID contains published

altitude and/or speed restrictions, those restrictions are canceled and pilots will receive an altitude to maintain

and, if necessary, a speed. ATC may also interrupt the vertical navigation of a SID and provide alternate altitude

instructions while the aircraft remains established on the published lateral path. Aircraft may be vectored off of

an ODP, or issued an altitude lower than a published altitude on an ODP, at which time the ODP is canceled. In

these cases, ATC assumes responsibility for terrain and obstacle clearance. In all cases, the minimum 200 FPNM

climb gradient is assumed.

4. Aircraft instructed to resume a SID procedure such as a DP or SID which contains speed and/or altitude

restrictions, must be:

(a) Issued/reissued all applicable restrictions, or

(b) Advised to “Climb via SID” or resume published speed.

EXAMPLE−

“Resume the Solar One departure, Climb via SID.”

“Proceed direct CIROS, resume the Solar One departure, Climb via SID.”

5. A clearance for a SID which does not contain published crossing restrictions, and/or is a SID with a Radar

Vector segment or a Radar Vector SID, will be issued using the phraseology “Maintain (altitude).”

6. A clearance for a SID which contains published altitude restrictions may be issued using the phraseology

“climb via.” Climb via is an abbreviated clearance that requires compliance with the procedure lateral path,

associated speed and altitude restrictions along the cleared route or procedure. Clearance to “climb via”

authorizes the pilot to:

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(a) When used in the IFR departure clearance, in a PDC, DCL or when cleared to a waypoint depicted

on a SID, to join the procedure after departure or to resume the procedure.

(b) When vertical navigation is interrupted and an altitude is assigned to maintain which is not contained

on the published procedure, to climb from that previously-assigned altitude at pilot’s discretion to the altitude

depicted for the next waypoint.

(c) Once established on the depicted departure, to navigate laterally and climb to meet all published or

assigned altitude and speed restrictions.

NOTE−

1. When otherwise cleared along a route or procedure that contains published speed restrictions, the pilot must comply with

those speed restrictions independent of a climb via clearance.

2. ATC anticipates pilots will begin adjusting speed the minimum distance necessary prior to a published speed restriction

so as to cross the waypoint/fix at the published speed. Once at the published speed ATC expects pilots will maintain the

published speed until additional adjustment is required to comply with further published or ATC assigned speed restrictions

or as required to ensure compliance with 14 CFR section 91.117.

3. If ATC interrupts lateral/vertical navigation while an aircraft is flying a SID, ATC must ensure obstacle clearance. When

issuing a “climb via” clearance to join or resume a procedure ATC must ensure obstacle clearance until the aircraft is

established on the lateral and vertical path of the SID.

4. ATC will assign an altitude to cross if no altitude is depicted at a waypoint/fix or when otherwise necessary/ required,

for an aircraft on a direct route to a waypoint/fix where the SID will be joined or resumed.

5. SIDs will have a “top altitude;” the “top altitude” is the charted “maintain” altitude contained in the procedure

description or assigned by ATC.

REFERENCE−

F AA Order JO 7110.65, Para 5-6-2, Methods.

PCG, Climb Via, Top Altitude.

EXAMPLE−

1. Lateral route clearance:

“Cleared Loop Six departure.”

NOTE−

The aircraft must comply with the SID lateral path, and any published speed restrictions.

2. Routing with assigned altitude:

“Cleared Loop Six departure, climb and maintain four thousand.”

NOTE−

The aircraft must comply with the SID lateral path, and any published speed restriction while climbing unrestricted to four

thousand.

3. (A pilot filed a flight plan to the Johnston Airport using the Scott One departure, Jonez transition, then Q-145. The pilot

filed for FL350. The Scott One includes altitude restrictions, a top altitude and instructions to expect the filed altitude ten

minutes after departure). Before departure ATC uses PDC, DCL or clearance delivery to issue the clearance:

“Cleared to Johnston Airport, Scott One departure, Jonez transition, Q-OneForty-five. Climb via SID.”

NOTE−

In Example 3, the aircraft must comply with the Scott One departure lateral path and any published speed and altitude

restrictions while climbing to the SID top altitude.

4. (Using the Example 3 flight plan, ATC determines the top altitude must be changed to FL180). The clearance will read:

“Cleared to Johnston Airport, Scott One departure, Jonez transition, Q-One Forty-five, Climb via SID except maintain

flight level one eight zero.”

NOTE−

In Example 4, the aircraft must comply with the Scott One departure lateral path and any published speed and altitude

restrictions while climbing to FL180. The aircraft must stop climb at FL180 until issued further clearance by ATC.

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5. (An aircraft was issued the Suzan Two departure, “climb via SID” in the IFR departure clearance. After departure ATC

must change a waypoint crossing restriction). The clearance will be:

“Climb via SID except cross Mkala at or above seven thousand.”

NOTE−

In Example 5, the aircraft will comply with the Suzan Two departure lateral path and any published speed and altitude

restrictions and climb so as to cross Mkala at or above 7,000; remainder of the departure must be flown as published.

6. (An aircraft was issued the Teddd One departure, “climb via SID” in the IFR departure clearance. An interim altitude

of 10,000 was issued instead of the published top altitude of FL 230). After departure ATC is able to issue the published top

altitude. The clearance will be:

“Climb via SID.”

NOTE−

In Example 6, the aircraft will track laterally and vertically on the Teddd One departure and initially climb to 10,000; Once

re-issued the “climb via” clearance the interim altitude is canceled aircraft will continue climb to FL230 while complying

with published restrictions.

7. (An aircraft was issued the Bbear Two departure, “climb via SID” in the IFR departure clearance. An interim altitude

of 16,000 was issued instead of the published top altitude of FL 190). After departure, ATC is able to issue a top altitude

of FL300 and still requires compliance with the published SID restrictions. The clearance will be:

“Climb via SID except maintain flight level three zero zero.”

NOTE−

In Example 7, the aircraft will track laterally and vertically on the Bbear Two departure and initially climb to 16,000; Once

re-issued the “climb via” clearance the interim altitude is canceled and the aircraft will continue climb to FL300 while

complying with published restrictions.

8. (An aircraft was issued the Bizee Two departure, “climb via SID.” After departure, ATC vectors the aircraft off of the

SID, and then issues a direct routing to rejoin the SID at Rockr waypoint which does not have a published altitude restriction.

ATC wants the aircraft to cross at or above 10,000). The clearance will read:

“Proceed direct Rockr, cross Rockr at or above one-zero thousand, climb via the Bizee Two departure.”

NOTE−

In Example 8, the aircraft will join the Bizee Two SID at Rockr at or above 10,000 and then comply with the published lateral

path and any published speed or altitude restrictions while climbing to the SID top altitude.

9. (An aircraft was issued the Suzan Two departure, “climb via SID” in the IFR departure clearance. After departure ATC

vectors the aircraft off of the SID, and then clears the aircraft to rejoin the SID at Dvine waypoint, which has a published

crossing restriction). The clearance will read:

“Proceed direct Dvine, Climb via the Suzan Two departure.”

NOTE−

In Example 9, the aircraft will join the Suzan Two departure at Dvine, at the published altitude, and then comply with the

published lateral path and any published speed or altitude restrictions.

7. Pilots cleared for vertical navigation using the phraseology “climb via” must inform ATC, upon initial

contact, of the altitude leaving and any assigned restrictions not published on the procedure.

EXAMPLE−

1. (Cactus 711 is cleared to climb via the Laura Two departure. The Laura Two has a top altitude of FL190):

“Cactus Seven Eleven leaving two thousand, climbing via the Laura Two departure.”

2. (Cactus 711 is cleared to climb via the Laura Two departure, but ATC changed the top altitude to16,000):

“Cactus Seven Eleven leaving two thousand for one-six thousand, climbing via the Laura Two departure.”

8. If prior to or after takeoff an altitude restriction is issued by ATC, all previously issued “ATC” altitude

restrictions are canceled including those published on a SID. Pilots must still comply with all speed restrictions

and lateral path requirements published on the SID unless canceled by ATC.

EXAMPLE−

Prior to takeoff or after departure ATC issues an altitude change clearance to an aircraft cleared to climb via a SID but ATC

no longer requires compliance with published altitude restrictions:

“Climb and maintain flight level two four zero.”

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NOTE−

The published SID altitude restrictions are canceled; The aircraft should comply with the SID lateral path and begin an

unrestricted climb to FL240. Compliance with published speed restrictions is still required unless specifically deleted by

ATC.

9. Altitude restrictions published on an ODP are necessary for obstacle clearance and/or design constraints.

Crossing altitudes and speed restrictions on ODPs cannot be canceled or amended by ATC.

i. PBN Departure Procedures

1. All public PBN SIDs and graphic ODPs are normally designed using RNA V 1, RNP 1, or A−RNP

NavSpecs. These procedures generally start with an initial track or heading leg near the departure end of runway

(DER). In addition, these procedures require system performance currently met by GPS or DME/DME/IRU PBN

systems that satisfy the criteria discussed in the latest AC 90−100, U.S. Terminal and En Route Area Navigation

(RNA V) Operations. RNA V 1 and RNP 1 procedures must maintain a total system error of not more than 1 NM

for 95 percent of the total flight time. Minimum values for A−RNP procedures will be charted in the PBN box

(for example, 1.00 or 0.30).

2. In the U.S., a specific procedure’s PBN requirement s will be prominently displayed in separate,

standardized notes boxes. For procedures with PBN elements, the “PBN box” will contain the procedure’s

NavSpec(s); and, if required: specific sensors or infrastructure needed for the navigation solution, any additional

or advanced functional requirements, the minimum RNP value, and any amplifying remarks. Items listed in this

PBN box are REQUIRED for the procedure’s PBN elements.

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Section 3. En Route Procedures

5−3−1. ARTCC Communications

a. Direct Communications, Controllers and Pilots.

1. ARTCCs are capable of direct communications with IFR air traffic on certain frequencies. Maximum

communications coverage is possible through the use of Remote Center Air/Ground (RCAG) sites comprised

of both VHF and UHF transmitters and receivers. These sites are located throughout the U.S. Although they may

be several hundred miles away from the ARTCC, they are remoted to the various ARTCCs by land lines or

microwave links. Since IFR operations are expedited through the use of direct communications, pilots are

requested to use these frequencies strictly for communications pertinent to the control of IFR aircraft. Flight plan

filing, en route weather, weather forecasts, and similar data should be requested through FSSs, company radio,

or appropriate military facilities capable of performing these services.

2. An ARTCC is divided into sectors. Each sector is handled by one or a team of controllers and has its own

sector discrete frequency. As a flight progresses from one sector to another, the pilot is requested to change to

the appropriate sector discrete frequency.

3. Controller Pilot Data Link Communications (CPDLC) is a system that supplements air/ground voice

communications. The CPDLC’s principal operating criteria are:

(a) V oice remains the primary and controlling air/ground communications means.

(b) Participating aircraft will need to have the appropriate CPDLC avionics equipment in order to receive

uplink or transmit downlink messages.

(c) En Route CPDLC offers many services including the following: Altimeter Setting (AS), Transfer of

Communications (TOC), Initial Contact (IC), route assignments, including airborne reroutes (ABRR), altitude

assignments, speed assignments, crossing constraints, holding, and advisory and emergency messages.

(1) Altimeter settings will be uplinked automatically when appropriate after a Monitor TOC. Altimeter

settings will also be uplinked automatically when an aircraft receives an uplinked altitude assignment below FL

180. A controller may also manually send an altimeter setting message.

NOTE−

When conducting instrument approach procedures, pilots are responsible to obtain and use the appropriate altimeter setting

in accordance with 14 CFR section 97.20. CPDLC issued altimeter settings are excluded for this purpose.

(2) Initial contact is a safety validation transaction that compares a pilot’s initiated altitude downlink

message with an aircraft’s stored altitude in the ATC automation system. When an IC mismatch or Confirm

Assigned Altitude (CAA) downlink time−out indicator is displayed in the Full Data Block (FDB) and Aircraft List

(ACL), the controller who has track control of the aircraft must use voice communication to verify the assigned

altitude of the aircraft, and acknowledge the IC mismatch/time−out indicator.

(3) Transfer of communications automatically establishes data link contact with a succeeding sector.

(4) Menu text transmissions are scripted nontrajectory altering uplink messages.

(5) The CPDLC Message Elements used in domestic en route operations are contained in TBL 5−3−1

through TBL 5−3−23, CPDLC Message Elements.

(6) For CPDLC Message Elements used in FAA oceanic control areas (KZWY , KZAK, and PAZA),

please refer to the U.S. AIP, ENR 7.2.

NOTE−

The F AA is not implementing ATN B1.

En Route Procedures 5−3−1

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TBL 5−3−1

Response Attribute of CPDLC Message Element

Response

Attribute

Description

For Uplink Message

W/U Response required.

Valid responses. WILCO, UNABLE, STANDBY, NOT CURRENT DATA AUTHORITY,

NOT AUTHORIZED NEXT DATA AUTHORITY, LOGICAL ACKNOWLEDGEMENT

(only if required), ERROR

Note – WILCO, UNABLE, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT

DATA AUTHORITY and ERROR will close the uplink message. FANS 1/A.– WILCO, UN-

ABLE, STANDBY, ERROR, NOT CURRENT DATA AUTHORITY.

A/N Response required.

Valid responses. AFFIRM, NEGATIVE, STANDBY, NOT CURRENT DATA AUTHORITY,

NOT AUTHORIZED NEXT DATA AUTHORITY, LOGICAL ACKNOWLEDGEMENT

(only if required), ERROR

Note – AFFIRM, NEGATIVE, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED

NEXT DATA AUTHORITY and ERROR will close the uplink message. FANS 1/A.– AFFIRM,

NEGATIVE, STANDBY, ERROR, NOT CURRENT DATA AUTHORITY.

R Response required.

Valid responses. ROGER, UNABLE, STANDBY, NOT CURRENT DATA AUTHORITY,

NOT AUTHORIZED NEXT DATA AUTHORITY, LOGICAL ACKNOWLEDGEMENT

(only if required), ERROR

Note – ROGER, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT DATA AU-

THORITY and ERROR will close the uplink message.

FANS 1/A.– ROGER, STANDBY, ERROR, NOT CURRENT DATA AUTHORITY. FANS

1/A aircraft do not have the capability to send UNABLE in response to an uplink message con-

taining message elements with an “R” response attribute. For these aircraft, the flight crew may

use alternative means to UNABLE the message. These alternative means will need to be taken

into consideration to ensure proper technical and operational closure of the communication

transaction.

Y Response required.

Valid responses: Any CPDLC downlink message, LOGICAL ACKNOWLEDGEMENT (only

if required).

N No response required unless logical acknowledgement is required.

Valid Responses (only if LOGICAL ACKNOWLEDGEMENT is required). LOGICAL AC-

KNOWLEDGEMENT, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT

DATA AUTHORITY, ERROR

FANS 1/A.– “N” is defined as “no response is required,” but not used. Under some circum-

stances, an ERROR message will also close an uplink message.

En Route Procedures5−3−2

AIM2/20/251/22/26 AIM

NE [Not defined in Doc 4444]

FANS 1/A.– The WILCO, UNABLE, AFFIRM, NEGATIVE, ROGER, and STANDBY re-

sponses are not enabled (NE) for flight crew selection. An uplink message with a response at-

tribute NE is considered to be closed even though a response may be required operationally.

Under some circumstances, a downlink error message may be linked to an uplink message with

a NE attribute.

For Downlink Message

Y Response required. Yes

Valid responses. Any CPDLC uplink message, LOGICAL ACKNOWLEDGEMENT (only if

required).

N Response required. No, unless logical acknowledgement required.

Valid responses (only if LOGICAL ACKNOWLEDGEMENT is required). LOGICAL AC-

KNOWLEDGEMENT, SERVICE UNAVAILABLE, FLIGHT PLAN NOT HELD, ERROR

FANS 1/A.– Aircraft do not have the capability to receive technical responses to downlink

message elements with an “N” response attribute (other than LACK or ERROR for ATN B1

aircraft). In some cases, the response attribute is different between FANS 1/A aircraft and Doc

4444. As an example, most emergency messages have an “N” response attribute for FANS 1/A

whereas Doc 4444 defines a “Y” response attribute for them. As a consequence, for FANS 1/A

aircraft, ATC will need to use alternative means to acknowledge to the flight crew that an

emergency message has been received.

TBL 5−3−2

Route Uplink Message Elements (RTEU)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element

Intended Use

Format for Message

Element Display

UM74 PROCEED

DIRECT TO (position)

W/U RTEU−2 Instruction to proceed

directly to the specified

position.

PROCEED DIRECT TO

(position)

UM75 WHEN ABLE

PROCEED DIRECT TO

(position)

Note – This message

element is equivalent to

SUPU−5 plus RTEU−2 in

Doc 4444.

W/U RTEU−2 Instruction to proceed,

when able, directly to the

specified position.

PROCEED DIRECT TO

(position)

UM77 AT (position)

PROCEED DIRECT TO

(position)

W/U RTEU−4 Instruction to proceed, at

the specified at position,

directly to the next

specified position.

AT (position) PROCEED

DIRECT TO (position)

UM78 AT (altitude)

PROCEED DIRECT TO

(position)

W/U RTEU−5 Instruction to proceed,

upon reaching the specified

level, directly to the

specified position.

AT (level) PROCEED

DIRECT TO (position)

UM79 CLEARED TO

(position) via (route

clearance)

W/U RTEU−6 Instruction to proceed to

the specified position via

the specified route.

CLEARED TO (position)

VIA (departure data[O])

(en−route data)

En Route Procedures 5−3−3

AIM 2/20/253/15/077110.65R CHG 2AIM 1/22/26

UM80 CLEARED (route

clearance)

W/U RTEU−7 Instruction to proceed via

the specified route.

CLEARED (departure

data[O]) (en−route data)

(arrival approach data)

UM83 AT (position)

CLEARED (route

clearance)

W/U RTEU−9 Instruction to proceed from

the specified position via

the specified route.

AT (position) CLEARED

(en−route data) (arrival

approach data)

UM91 HOLD AT

(position) MAINTAIN

(altitude) INBOUND

TRACK (degrees)

(direction) TURN LEG

TIME (leg type)

W/U RTEU−11 Instruction to enter a

holding pattern at the

specified position in

accordance with the

specified instructions.

Note– RTEU−13 EXPECT

FURTHER CLEARANCE

AT TIME (time) is

appended to this message

when an extended hold is

anticipated.

AT (position) HOLD

INBOUND TRACK

(degrees)(direction)

TURNS (leg type) LEGS

UM92 HOLD AT

(position) AS

PUBLISHED MAINTAIN

(altitude)

W/U RTEU−12 Instruction to enter a

holding pattern at the

specified position in

accordance with the

published holding

instructions.

Note – RTEU−13 EXPECT

FURTHER CLEARANCE

AT TIME (time) is

appended to this message

when an extended hold is

anticipated.

AT (position) HOLD AS

PUBLISHED

UM93 EXPECT

FURTHER CLEARANCE

AT (time)

W/U RTEU−13 Notification that an

onwards clearance may be

issued at the specified time

EXPECT FURTHER

CLEARANCE AT (time)

UM137 CONFIRM

ASSIGNED ROUTE

Note – NE response

attribute.

W/U RTEU−15 Request to confirm the

assigned route.

CONFIRM ASSIGNED

ROUTE

TBL 5−3−3

Route Downlink Message Elements (RTED)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element

Intended Use

Format for Message

Element Display

DM22 REQUEST

DIRECT TO (position)

Y RTED−1 Request for a direct

clearance to the specified

position.

REQUEST DIRECT TO

(position)

DM23 REQUEST

(procedure name)

Y RTED−2 Request for the specified

procedure or clearance

name

REQUEST (named

instruction)

En Route Procedures5−3−4

AIM2/20/251/22/26 AIM

DM24 REQUEST (route

clearance)

Y RTED−3 Request for the specified

route.

REQUEST CLEARANCE

(departure data[O])

(en−route data) (arrival

approach data[O])

DM40 ASSIGNED

ROUTE (route clearance)

N RTED−9 Confirmation that the

assigned route is the

specified route.

ASSIGNED ROUTE

(departure data[O])

(en−route data) (arrival

approach data[O])

TBL 5−3−4

Lateral Uplink Message Elements (LATU)

FANS 1/A Response

Message

Element

Identifier

Message Element

Intended Use

Format for Message

Element Display

UM82 CLEARED TO

DEVIATE UP TO

(distance offset) (direction)

OF ROUTE

W/U LATU−10 Instruction allowing

deviation up to the

specified distance(s) from

the cleared route in the

specified direction(s).

CLEARED TO DEVIATE

UP TO (lateral deviation)

OF ROUTE

UM127 REPORT BACK

ON ROUTE

Note – R response

attribute.

W/U LATU−18 Instruction to report when

the aircraft is back on the

cleared route.

REPORT BACK ON

ROUTE

TBL 5−3−5

Lateral Downlink Message Elements (LATD)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element Intended

Use

Format for Message

Element Display

DM27 REQUEST

WEATHER

DEVIATION UP TO

(specified distance)

(direction) OF

ROUTE

Y LATD−2 Request for a weather

deviation up to the specified

distance off track in the

specified direction.

REQUEST WEATHER

DEVIATION UP TO

(specified distance) (direction)

OF ROUTE

DM41 BACK ON

ROUTE

N LATD−4 The aircraft has regained the

cleared route.

BACK ON ROUTE

DM59 DIVERTING

TO (position) VIA

(route clearance)

Note 1. − H alert

attribute

Note 2. − N

response attribute

See Note

LATD−5 Report indicating diverting to

the specified position via the

specified route, which may be

sent without any previous

coordination done with ATC.

DIVERTING TO (position)

VIA (en−route data) (arrival

approach data[O])

En Route Procedures 5−3−5

AIM 2/20/253/15/077110.65R CHG 2AIM 1/22/26

OFFSETTING

(distance offset)

(direction) OF

ROUTE

Note 1. − H alert

attribute

Note 2. − N

response attribute

See Note

LATD−6 Report indicating that the

aircraft is offsetting to a

parallel track at the specified

distance in the specified

direction off from the cleared

route.

OFFSETTING (specified

distance) (direction) OF

ROUTE

DM80 DEVIATING

(deviation offset)

(direction) OF

ROUTE

Note 1. − H alert

attribute

Note 2. − N response

attribute

See Note

LATD−7 Report indicating deviating

specified distance or degrees

in the specified direction from

the cleared route.

DEVIATING (specified

Deviation) (direction) OF

ROUTE

NOTE−

ICAO Document 10037, Global Operational Data Link (GOLD) Manual, has these values set to Y in their table.

TBL 5−3−6

Level Uplink Message Elements (LVLU)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element Intended

Use

Format for Message

Element Display

UM19 MAINTAIN

(altitude)

Note − Used for a

single level

W/U LVLU−5 Instruction to maintain the

specified level or vertical

range.

MAINTAIN (level)

UM20 CLIMB TO

AND MAINTAIN

(altitude)

Note − Used for a

single level

W/U LVLU−6 Instruction that a climb to the

specified level or vertical

range is to commence and

once reached is to be

maintained.

CLIMB TO (level)

UM23 DESCEND TO

AND MAINTAIN

(altitude)

Note − Used for a

single level

W/U LVLU−9 Instruction that a descent

to the specified level or

vertical range is to

commence and once

reached is to be

maintained.

DESCEND TO (level)

UM30 MAINTAIN

BLOCK (altitude) TO

(altitude)

Note – Used for a

vertical range

W/U LVLU−5 Instruction to maintain the

specified level or vertical

range.

MAINTAIN (level)

UM31 CLIMB TO

AND MAINTAIN

BLOCK (altitude) TO

(altitude)

Note – Used for a

vertical range

W/U LVLU−6 Instruction that a climb to the

specified level or vertical

range is to commence and

once reached is to be

maintained.

CLIMB TO (level)

En Route Procedures5−3−6

AIM2/20/251/22/26 AIM

UM32 DESCEND TO

AND MAINTAIN

BLOCK (altitude) TO

(altitude)

Note – Used for a

vertical range

W/U LVLU−9 Instruction that a descent to

the specified level or vertical

range is to commence and

once reached is to be

maintained.

DESCEND TO (level)

UM36 EXPEDITE W/U LVLU−6 Instruction that a climb to the CLIMB TO (level)

CLIMB TO (altitude) specified level or vertical

Note − This message range is to commence and

element is equivalent once reached is to be

to SUPU−3 plus maintained.

LVLU−6 in Doc 4444.

UM37 EXPEDITE

DESCEND TO

(altitude)

Note – This message

element is equivalent

to SUPU−5 plus

LVLU−9 in Doc 4444.

W/U LVLU−9 Instruction that a descent to

the specified level or vertical

range is to commence and

once reached is to be

maintained.

DESCEND TO (level)

UM38

IMMEDIA TELY

CLIMB TO (altitude)

Note − This message

element is equivalent

to EMGU−2 plus

LVLU−6 in Doc 4444.

W/U LVLU−6 Instruction that a climb to the

specified level or vertical

range is to commence and

once reached is to be

maintained.

CLIMB TO (level)

UM39

IMMEDIA TELY

DESCEND TO

(altitude)

Note − This message

element is equivalent

to EMGU−2 plus

LVLU−9 in Doc 4444.

W/U LVLU−9 Instruction that a descent to

the specified level or vertical

range is to commence and

once reached is to be

maintained.

DESCEND TO (level)

UM135 CONFIRM

ASSIGNED

ALTITUDE

Note − NE response

attribute

Y LVLU−27 Request to confirm the

assigned level.

CONFIRM ASSIGNED

LEVEL

UM177 AT PILOTS NE See Note An instruction used in

DISCRETION conjunction with altitude

assignments, means that ATC

has offered the pilot the

option of starting climb or

descent whenever they wish

and conducting the climb or

descent at any rate they wish.

The pilot may temporarily

level off at any intermediate

altitude. However, once the

aircraft has vacated an

altitude, it may not return to

that altitude.

En Route Procedures 5−3−7

AIM 2/20/253/15/077110.65R CHG 2AIM 1/22/26

NOTE−

ICAO Document 10037, Global Operational Data Link (GOLD) Manual, does not include this in its tables.

TBL 5−3−7

Level Downlink Message Elements (LVLD)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element Intended

Use

Format for Message

Element Display

DM6 REQUEST

(altitude)

Note − Used for a

single level

Y LVLD−1 Request to fly at the specified

level or vertical range.

REQUEST (level)

DM7 REQUEST

BLOCK (altitude) TO

(altitude)

Note – Used for a

vertical range.

Y LVLD−1 Request to fly at the specified

level or vertical range.

REQUEST (level)

DM9 REQUEST

CLIMB TO (altitude)

Y LVLD−2 Request for a climb to the

specified level or vertical

range.

REQUEST CLIMB TO

(level)

DM10 REQUEST

DESCENT TO

(altitude)

Y LVLD−3 Request for a descent to the

specified level or vertical

range.

REQUEST DESCENT TO

(level)

DM38 ASSIGNED

LEVEL (altitude)

Note − Used for a

single level

N LVLD−11 Confirmation that the

assigned level or vertical

range is the specified level or

vertical range.

ASSIGNED LEVEL (level)

DESCENDING TO

(altitude)

Note − urgent alert

attribute

N LVLD−14 Report indicating descending

to the specified level.

DESCENDING TO (level

single)

DM77 ASSIGNED

BLOCK (altitude) TO

(altitude)

Note– Used for a

vertical range

N LVLD−11 Confirmation that the

assigned level or vertical

range is the specified level or

vertical range.

ASSIGNED LEVEL (level)

En Route Procedures5−3−8

AIM2/20/251/22/26 AIM

TBL 5−3−8

Crossing Constraint Message Elements (CSTU)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element Intended

Use

Format for Message

Element Display

UM46 CROSS

(position) AT

(altitude)

Note – Used for a

single level.

W/U CSTU−1 Instruction that the specified

position is to be crossed at the

specified level or within the

specified vertical range.

CROSS (position) AT (level)

UM49 CROSS

(position) AT AND

MAINTAIN (altitude)

Note 1. − A vertical

range cannot be

provided.

Note 2. − This

message element is

equivalent to CSTU−1

plus LVLU−5 in

Doc 4444.

W/U CSTU−1 Instruction that the specified

position is to be crossed at the

specified level or within the

specified vertical range.

CROSS (position) AT (level)

UM51 CROSS

(position) AT (time)

W/U CSTU−4 Instruction that the specified

position is to be crossed at the

specified time.

CROSS (position) AT TIME

(time)

UM52 CROSS

(position) AT OR

BEFORE (time)

W/U CSTU−5 Instruction that the specified

position is to be crossed

before the specified time.

CROSS (position) BEFORE

TIME (time)

UM53 CROSS

(position) AT OR

AFTER (time)

W/U CSTU−6 Instruction that the specified

position is to be crossed after

the specified time.

CROSS (position) AFTER

TIME (time)

UM55 CROSS

(position) AT (speed)

W/U CSTU−8 Instruction that the specified

position is to be crossed at the

specified speed.

CROSS (position) AT (speed)

UM56 CROSS

(position) AT OR

LESS THAN (speed)

W/U CSTU−9 Instruction that the specified

position is to be crossed at or

less than the specified speed.

CROSS (position) AT (speed)

OR LESS

UM57 CROSS

(position) AT OR

GREATER THAN

(speed)

W/U CSTU−10 Instruction that the specified

position is to be crossed at or

greater than the specified

speed.

CROSS (position) AT (speed)

OR GREATER

UM61 CROSS

(position) AT AND

MAINTAIN (altitude)

AT (speed)

Note 1. − A vertical

range cannot be

provided.

Note 2. − This

message element is

equivalent to

CSTU−14 plus

LVLU−5 in Doc 4444.

W/U CSTU−14 Instruction that the specified

position is to be crossed at the

level or within the vertical

range, as specified, and at the

specified speed.

CROSS (position) AT (level)

AT (speed)

En Route Procedures 5−3−9

AIM 2/20/253/15/077110.65R CHG 2AIM 1/22/26

TBL 5−3−9

Speed Uplink Message Elements (SPDU)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element Intended

Use

Format for Message

Element Display

UM106 MAINTAIN

(speed)

W/U SPDU−4 Instruction to maintain the

specified speed.

MAINTAIN (speed)

UM107 MAINTAIN

PRESENT SPEED

W/U SPDU−5 Instruction to maintain the

specified speed.

MAINTAIN PRESENT

SPEED

UM108 MAINTAIN

(speed) OR

GREATER

W/U SPDU−6 Instruction to maintain the

specified speed or greater.

MAINTAIN (speed) OR

GREA TER

UM109 MAINTAIN

(speed) OR LESS

W/U SPDU−7 Instruction to maintain the

specified speed or less.

MAINTAIN PRESENT

(speed) OR LESS

UM116 RESUME

NORMAL SPEED

W/U SPDU−13 Instruction to resume a

normal speed. The aircraft no

longer needs to comply with a

previously issued speed

restriction.

RESUME NORMAL SPEED

UM134 CONFIRM

SPEED

Note – NE response

attribute.

Y SPDU−15 Request to report the speed

defined by the speed type(s).

REPORT (speed types)

SPEED

TBL 5−3−10

Speed Downlink Message Elements

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element Intended

Use

Format for Message

Element Display

DM34 PRESENT

SPEED (speed)

N SPDD−3 Report indicating the speed

defined by the specified speed

types is the specified speed.

(speed types) SPEED (speed)

TBL 5−3−11

Air Traffic Advisory Uplink Message Elements

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element Intended

Use

Format for Message

Element Display

UM154 RADAR

SERVICES

TERMINA TED

R ADVU−2 Advisory that the ATS

surveillance service is

terminated.

SURVEILLANCE SERVICE

TERMINA TED

En Route Procedures5−3−10

AIM2/20/251/22/26 AIM

TBL 5−3−12

Voice Communications Uplink Message Elements (COMU)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element Intended

Use

Format for Message

Element Display

UM117 CONTACT

(ICAO unit name)

(frequency)

W/U COMU−1 Instruction to establish voice

contact with the specified

ATS unit on the specified

frequency.

CONTACT (unit name)

(frequency)

UM120 MONITOR

(ICAO unit name)

(frequency)

W/U COMU−5 Instruction to monitor the

specified ATS unit on the

specified frequency. The

flight crew is not required to

establish voice contact on the

frequency.

MONITOR (unit name)

(frequency)

TBL 5−3−13

Voice Communications Downlink Message Elements (COMD)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element

Intended Use Format for Message Element Display

DM20 REQUEST

VOICE CONTACT

Note − Used when a

frequency is not

required.

Y COMD−1 Request for voice

contact on the

specified frequency.

REQUEST VOICE CONTACT

(frequency)

TBL 5−3−14

Emergency/Urgency Uplink Message Elements (EMGU)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element

Intended Use

Format for Message Element

Display

UM38 IMMEDIATELY

CLIMB TO (altitude)

Used in combination with

LVLU−6 and LVLU−9,

which is implemented in

FANS 1/A as above

N EMGU−2 Instruction to

immediately

comply with the

associated

instruction to avoid

imminent situation.

Immediately

UM39 IMMEDIATELY

DESCEND TO (altitude)

Used in combination with

LVLU−6 and LVLU−9,

which is implemented in

FANS 1/A as above

N EMGU−2 Instruction to

immediately

comply with the

associated

instruction to avoid

imminent situation.

Immediately

En Route Procedures 5−3−11

AIM 2/20/253/15/077110.65R CHG 2AIM 1/22/26

TBL 5−3−15

Emergency/Urgency Downlink Message Elements (EMGD)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element

Intended Use Format for Message Element Display

DM55 PAN PAN PAN

Note − N response

attribute

Y EMGD−1 Indication of an

urgent situation.

PAN PAN PAN

DM56 MAYDAY

MAYDAY MAYDAY

Note − N response

attribute

Y EMGD−2 Indication of an

emergency

situation.

MAYDAY

MAYDAY

MAYDAY

DM57 (remaining

fuel) OF FUEL

REMAINING AND

(remaining souls)

SOULS ON BOARD

Note − N response

attribute

Y EMGD−3 Report indicating

fuel remaining

(time) and number

of persons on board.

(remaining fuel) ENDURANCE AND

(persons on board) PERSONS ON

BOARD

DM58 CANCEL

EMERGENCY

Note − N response

attribute

Y EMGD−4 Indication that the

emergency situation

is canceled.

CANCEL EMERGENCY

TBL 5−3−16

Standard Response Uplink Message Elements (RSPU)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element

Intended Use Format for Message Element Display

UM0 UNABLE N RSPU−1 Indication that the

message cannot be

complied with.

UNABLE

UM1 STANDBY N RSPU−2 Indication that the

message will be

responded to

shortly.

STANDBY

UM3 ROGER N RSPU−4 Indication that the

message is

received.

ROGER

TBL 5−3−17

Standard Response Downlink Message Elements (RSPD)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element

Intended Use Format for Message Element Display

DM0 WILCO N RSPD−1 Indication that the

instruction is

understood and will

be complied with.

WILCO

En Route Procedures5−3−12

AIM2/20/251/22/26 AIM

DM1 UNABLE N RSPD−2 Indication that the

message cannot be

complied with.

UNABLE

DM2 STANDBY N RSPD−3 Indication that the

message will be

responded to

shortly.

STANDBY

DM3 ROGER

Note − ROGER is the

only correct response

to an uplink free text

message.

N RSPD−4 Indication that the

message is

received.

ROGER

TBL 5−3−18

Supplemental Uplink Message Elements (SUPU)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element

Intended Use Format for Message Element Display

UM166 DUE TO

TRAFFIC

N SUPU−2 Indication that the

associated message

is issued due to the

specified reason.

DUE TO (specified reason uplink)

UM167 DUE TO

AIRSPACE

RESTRICTION

N SUPU−2 Indication that the

associated message

is issued due to the

specified reason.

DUE TO (specified reason uplink)

TBL 5−3−19

Supplemental Downlink Message Elements (SUPD)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element

Intended Use Format for Message Element Display

DM65 DUE TO

WEATHER

N SUPD−1 Indication that the

associated message

is issued due to the

specified reason.

DUE TO (specified reason uplink)

DM66 DUE TO

AIRCRAFT

PERFORMANCE

N SUPD−1 Indication that the

associated message

is issued due to the

specified reason.

DUE TO (specified reason downlink)

En Route Procedures 5−3−13

AIM 2/20/253/15/077110.65R CHG 2AIM 1/22/26

TBL 5−3−20

Free Text Uplink Message Elements (TXTU)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element

Intended Use

Format for Message Element

Display

UM169 (free text) R TXTU−1 A message or part

of a message that

does not conform to

any standard

message element in

the PANS−ATM

(Doc 4444).

(free text)

Note−M alert attribute.

UM169 Advisory (free

text)

R TXTU−1 (free text)

UM169 (free text)

CPDLC NOT IN USE

UNTIL FURTHER

NOTIFICA TION

R See Note (free text)

UM169 (free text)

“[facility designation]”

LOCAL ALTIMETER

(for Altimeter

Reporting Station)

R See Note (free text)

UM169 (free text)

“[facility designation]

LOCAL ALTIMETER

MORE THAN ONE

HOUR” OLD

R See Note (free text)

UM169 (free text)

DUE TO WEATHER

R See Note (free text)

UM169 (free text)

REST OF ROUTE

UNCHANGED

R See Note (free text)

UM169 (free text)

TRAFFIC FLOW

MANAGEMENT

REROUTE

R See Note (free text)

UM169 (free text)

DUE TO SPACING

R See Note (free text)

UM169 (free text) ATC

HAS YOUR

REQUEST

R See Note (free text)

UM169 (free text) ATC

ADVISORY

R See Note (free text)

NOTE−

These are F AA scripted free text messages with no GOLD equivalent.

En Route Procedures5−3−14

AIM2/20/251/22/26 AIM

TBL 5−3−21

Free Text Downlink Message Elements (TXTD)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element

Intended Use

Format for Message Element

Display

DM68 (free text)

Note 1. − Urgency or Distress

Alr (M)

Note 2. − Selecting any of the

emergency message elements

will result in this message

element being enabled for the

flight crew to include in the

emergency message at their

discretion.

Y TXTD−1 (free text)

Note − M alert attribute.

TBL 5−3−22

System Management Uplink Message Elements (SYSU)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element

Intended Use

Format for Message Element

Display

UM159 ERROR (error

information)

N SYSU−1 System−generated

notification of an

error.

ERROR (error information)

UM160 NEXT DATA

AUTHORITY (ICAO

facility designation)

Note − The facility

designation is required.

N SYSU−2 System−generated

notification of the

next data authority

or the cancellation

thereof.

NEXT DATA AUTHORITY (facility

designation [O])

TBL 5−3−23

System Management Downlink Message Elements (SYSD)

CPDLC Message Sets Operational Definition in PANS−ATM (Doc 4444)

FANS 1/A Response

Message

Element

Identifier

Message Element

Intended Use

Format for Message Element

Display

DM62 ERROR (error

information)

N SYSD−1 System−generated

notification of an

error.

SYSD−1

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DM63 NOT N SYSD−3 System−generated SYSD−3

CURRENT DATA rejection of any

AUTHORITY CPDLC message

sent from a ground

facility that is not

the current data

authority.

DM64 (ICAO facility

designation)

Note − Use by F ANS

1/A aircraft in B1

environments.

N SYSD−5 System−generated

notification that the

ground system is

not designated as

the next data

authority (NDA),

indicating the

identity of the

current data

authority (CDA).

Identity of the

NDA, if any, is also

reported.

SYSD−5

b. ATC Frequency Change Procedures.

1. The following phraseology will be used by controllers to effect a frequency change:

EXAMPLE−

(Aircraft identification) contact (facility name or location name and terminal function) (frequency) at (time, fix, or altitude).

NOTE−

Pilots are expected to maintain a listening watch on the transferring controller’ s frequency until the time, fix, or altitude

specified. ATC will omit frequency change restrictions whenever pilot compliance is expected upon receipt.

2. The following phraseology should be utilized by pilots for establishing contact with the designated

facility:

(a) When operating in a radar environment: On initial contact, the pilot should inform the controller of

the aircraft’s assigned altitude preceded by the words “level,” or “climbing to,” or “descending to,” as

appropriate; and the aircraft’s present vacating altitude, if applicable.

EXAMPLE−

1. (Name) CENTER, (aircraft identification), LEVEL (altitude or flight level).

2. (Name) CENTER, (aircraft identification), LEAVING (exact altitude or flight level), CLIMBING TO OR DESCENDING

TO (altitude of flight level).

NOTE−

Exact altitude or flight level means to the nearest 100 foot increment. Exact altitude or flight level reports on initial contact

provide ATC with information required prior to using Mode C altitude information for separation purposes.

(b) When operating in a nonradar environment:

(1) On initial contact, the pilot should inform the controller of the aircraft’s present position, altitude

and time estimate for the next reporting point.

EXAMPLE−

(Name) CENTER, (aircraft identification), (position), (altitude), ESTIMATING (reporting point) AT (time).

(2) After initial contact, when a position report will be made, the pilot should give the controller a

complete position report.

EXAMPLE−

(Name) CENTER, (aircraft identification), (position), (time), (altitude), (type of flight plan), (ETA and name of next

reporting point), (the name of the next succeeding reporting point), AND (remarks).

En Route Procedures5−3−16

AIM2/20/251/22/26 AIM

REFERENCE−

AIM, Para 5−3−2, Position Reporting.

3. At times controllers will ask pilots to verify that they are at a particular altitude. The phraseology used

will be: “VERIFY AT (altitude).” In climbing or descending situations, controllers may ask pilots to “VERIFY

ASSIGNED ALTITUDE AS (altitude).” Pilots should confirm that they are at the altitude stated by the controller

or that the assigned altitude is correct as stated. If this is not the case, they should inform the controller of the

actual altitude being maintained or the different assigned altitude.

CAUTION−

Pilots should not take action to change their actual altitude or different assigned altitude to the altitude stated in the

controllers verification request unless the controller specifically authorizes a change.

c. ARTCC Radio Frequency Outage. ARTCCs normally have at least one back-up radio receiver and

transmitter system for each frequency, which can usually be placed into service quickly with little or no

disruption of ATC service. Occasionally, technical problems may cause a delay but switchover seldom takes

more than 60 seconds. When it appears that the outage will not be quickly remedied, the ARTCC will usually

request a nearby aircraft, if there is one, to switch to the affected frequency to broadcast communications

instructions. It is important, therefore, that the pilot wait at least 1 minute before deciding that the ARTCC has

actually experienced a radio frequency failure. When such an outage does occur, the pilot should, if workload

and equipment capability permit, maintain a listening watch on the affected frequency while attempting to

comply with the following recommended communications procedures:

1. If two-way communications cannot be established with the ARTCC after changing frequencies, a pilot

should attempt to recontact the transferring controller for the assignment of an alternative frequency or other

instructions.

2. When an ARTCC radio frequency failure occurs after two-way communications have been established,

the pilot should attempt to reestablish contact with the center on any other known ARTCC frequency, preferably

that of the next responsible sector when practicable, and ask for instructions. However, when the next normal

frequency change along the route is known to involve another ATC facility, the pilot should contact that facility,

if feasible, for instructions. If communications cannot be reestablished by either method, the pilot is expected

to request communications instructions from the FSS appropriate to the route of flight.

NOTE−

The exchange of information between an aircraft and an ARTCC through an FSS is quicker than relay via company radio

because the FSS has direct interphone lines to the responsible ARTCC sector. Accordingly, when circumstances dictate a

choice between the two, during an ARTCC frequency outage, relay via FSS radio is recommended.

d. Oakland Oceanic FIR. The use of CPDLC and ADS−C in the Oakland Oceanic FIR (KZAK) is only

permitted by Inmarsat and Iridium customers. All other forms of data link connectivity are not authorized. Users

must ensure that the proper data link code is filed in Item 10a of the ICAO FPL in order to indicate which satellite

medium(s) the aircraft is equipped with. The identifier for Inmarsat is J5 and the identifier for Iridium is J7. If

J5 or J7 is not included in the ICAO FPL, then the LOGON will be rejected by KZAK and the aircraft will not

be able to connect.

e. New Y ork Oceanic FIR. The use of CPDLC and ADS−C in the New York Oceanic FIR (KZWY) is only

permitted by Inmarsat and Iridium customers. All other forms of data link connectivity are not authorized. Users

must ensure that the proper data link code is filed in Item 10a of the ICAO FPL in order to indicate which satellite

medium(s) the aircraft is equipped with. The identifier for Inmarsat is J5 and the identifier for Iridium is J7. If

J5 or J7 is not included in the ICAO FPL, then the LOGON will be rejected by KZWY and the aircraft will not

be able to connect.

5−3−2. Position Reporting

The safety and effectiveness of traffic control depends to a large extent on accurate position reporting. In order

to provide the proper separation and expedite aircraft movements, ATC must be able to make accurate estimates

of the progress of every aircraft operating on an IFR flight plan.

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AIM 2/20/253/15/077110.65R CHG 2AIM 1/22/26

a. Position Identification.

1. When a position report is to be made passing a VOR radio facility, the time reported should be the time

at which the first complete reversal of the “to/from” indicator is accomplished.

2. When a position report is made passing a facility by means of an airborne ADF, the time reported should

be the time at which the indicator makes a complete reversal.

3. When an aural or a light panel indication is used to determine the time passing a reporting point, such

as a fan marker, Z marker, cone of silence or intersection of range courses, the time should be noted when the

signal is first received and again when it ceases. The mean of these two times should then be taken as the actual

time over the fix.

4. If a position is given with respect to distance and direction from a reporting point, the distance and

direction should be computed as accurately as possible.

5. Except for terminal area transition purposes, position reports or navigation with reference to aids not

established for use in the structure in which flight is being conducted will not normally be required by ATC.

b. Position Reporting Points. CFRs require pilots to maintain a listening watch on the appropriate

frequency and, unless operating under the provisions of subparagraph c, to furnish position reports passing

certain reporting points. Reporting points are indicated by symbols on en route charts. The designated

compulsory reporting point symbol is a solid triangle

and the “on request” reporting point symbol is the open

triangle

. Reports passing an “on request” reporting point are only necessary when requested by ATC.

c. Position Reporting Requirements.

1. Flights Along Airways or Routes. A position report is required by all flights regardless of altitude,

including those operating in accordance with an ATC clearance specifying “VFR−on−top,” over each designated

compulsory reporting point along the route being flown.

2. Flights Along a Direct Route. Regardless of the altitude or flight level being flown, including flights

operating in accordance with an A TC clearance specifying “VFR−on−top,” pilots must report over each reporting

point used in the flight plan to define the route of flight.

3. Flights in a Radar Environment. When informed by ATC that their aircraft are in “Radar Contact,”

pilots should discontinue position reports over designated reporting points. They should resume normal position

reporting when ATC advises “RADAR CONTACT LOST” or “RADAR SERVICE TERMINATED.”

4. Flights in an Oceanic (Nonradar) Environment. Pilots must report over each point used in the flight

plan to define the route of flight, even if the point is depicted on aeronautical charts as an “on request”

(non-compulsory) reporting point. For aircraft providing automatic position reporting via an Automatic

Dependent Surveillance-Contract (ADS-C) logon, pilots should discontinue voice position reports.

NOTE−

ATC will inform pilots that they are in “radar contact”:

(a) when their aircraft is initially identified in the ATC system; and

(b) when radar identification is reestablished after radar service has been terminated or radar contact lost.

Subsequent to being advised that the controller has established radar contact, this fact will not be repeated to the pilot when

handed off to another controller. At times, the aircraft identity will be confirmed by the receiving controller; however, this

should not be construed to mean that radar contact has been lost. The identity of transponder equipped aircraft will be

confirmed by asking the pilot to “ident,” “squawk standby,” or to change codes. Aircraft without transponders will be

advised of their position to confirm identity. In this case, the pilot is expected to advise the controller if in disagreement with

the position given. Any pilot who cannot confirm the accuracy of the position given because of not being tuned to the NAVAID

referenced by the controller , should ask for another radar position relative to the tuned in NAVAID.

d. Position Report Items:

1. Position reports should include the following items:

(a) Identification;

En Route Procedures5−3−18

AIM2/20/251/22/26 AIM

(b) Position;

(c) Time;

(d) Altitude or flight level (include actual altitude or flight level when operating on a clearance specifying

VFR−on−top);

(e) Type of flight plan (not required in IFR position reports made directly to ARTCCs or approach

control);

(f) ETA and name of next reporting point;

(g) The name only of the next succeeding reporting point along the route of flight; and

(h) Pertinent remarks.

5−3−3. Additional Reports

a. The following reports should be made to ATC or FSS facilities without a specific ATC request:

1. At all times.

(a) When vacating any previously assigned altitude or flight level for a newly assigned altitude or flight

level.

(b) When an altitude change will be made if operating on a clearance specifying VFR−on−top.

(c) When unable to climb/descend at a rate of a least 500 feet per minute.

(d) When approach has been missed. (Request clearance for specific action; i.e., to alternative airport,

another approach, etc.)

(e) Change in the average true airspeed (at cruising altitude) when it varies by 5 percent or 10 knots

(whichever is greater) from that filed in the flight plan.

(f) The time and altitude or flight level upon reaching a holding fix or point to which cleared.

(g) When leaving any assigned holding fix or point.

NOTE−

The reports in subparagraphs (f) and (g) may be omitted by pilots of aircraft involved in instrument training at military

terminal area facilities when radar service is being provided.

(h) Any loss, in controlled airspace, of VOR, TACAN, ADF, low frequency navigation receiver

capability, GPS anomalies while using installed IFR−certified GPS/GNSS receivers, complete or partial loss of

ILS receiver capability or impairment of air/ground communications capability. Reports should include aircraft

identification, equipment affected, degree to which the capability to operate under IFR in the ATC system is

impaired, and the nature and extent of assistance desired from ATC.

NOTE−

1. Other equipment installed in an aircraft may effectively impair safety and/or the ability to operate under IFR. If such

equipment (e.g., airborne weather radar) malfunctions and in the pilot’ s judgment either safety or IFR capabilities are

affected, reports should be made as above.

2. When reporting GPS anomalies, include the location and altitude of the anomaly. Be specific when describing the

location and include duration of the anomaly if necessary.

(i) Any information relating to the safety of flight.

2. When not in radar contact.

(a) When leaving final approach fix inbound on final approach (nonprecision approach) or when leaving

the outer marker or fix used in lieu of the outer marker inbound on final approach (precision approach).

(b) A corrected estimate at anytime it becomes apparent that an estimate as previously submitted is in

error in excess of 2 minutes. For flights in the North Atlantic (NAT), a revised estimate is required if the error

is 3 minutes or more.

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b. Pilots encountering weather conditions which have not been forecast, or hazardous conditions which have

been forecast, are expected to forward a report of such weather to ATC.

REFERENCE−

AIM, Para 7−1−18, Pilot Weather Reports (PIREPs).

14 CFR Section 91.183(B) and (C).

5−3−4. Airways and Route Systems

a. Three fixed route systems are established for air navigation purposes. They are the Federal airway system

(consisting of VOR and L/MF routes), the jet route system, and the RNA V route system. To the extent possible,

these route systems are aligned in an overlying manner to facilitate transition between each.

1. The VOR and L/MF (nondirectional radio beacons) Airway System consists of airways designated from

1,200 feet above the surface (or in some instances higher) up to but not including 18,000 feet MSL. These airways

are depicted on IFR Enroute Low Altitude Charts.

NOTE−

The altitude limits of a victor airway should not be exceeded except to effect transition within or between route structures.

(a) Except in Alaska, the VOR airways are: predicated solely on VOR or VORTAC navigation aids;

depicted in black on aeronautical charts; and identified by a “V” (Victor) followed by the airway number (for

example, V12).

NOTE−

Segments of VOR airways in Alaska are based on L/MF navigation aids and charted in brown instead of black on en route

charts.

(1) A segment of an airway which is common to two or more routes carries the numbers of all the

airways which coincide for that segment. When such is the case, pilots filing a flight plan need to indicate only

that airway number for the route filed.

NOTE−

A pilot who intends to make an airway flight, using VOR facilities, will simply specify the appropriate “victor” airway(s)

in the flight plan. For example, if a flight is to be made from Chicago to New Orleans at 8,000 feet, using omniranges only,

the route may be indicated as “departing from Chicago−Midway, cruising 8,000 feet via Victor 9 to Moisant International.”

If flight is to be conducted in part by means of L/MF navigation aids and in part on omniranges, specifications of the

appropriate airways in the flight plan will indicate which types of facilities will be used along the described routes, and, for

IFR flight, permit ATC to issue a traffic clearance accordingly. A route may also be described by specifying the station over

which the flight will pass, but in this case since many VORs and L/MF aids have the same name, the pilot must be careful

to indicate which aid will be used at a particular location. This will be indicated in the route of flight portion of the flight

plan by specifying the type of facility to be used after the location name in the following manner: Newark L/MF , Allentown

VOR.

(2) With respect to position reporting, reporting points are designated for VOR Airway Systems.

Flights using Victor Airways will report over these points unless advised otherwise by ATC.

(b) The L/MF airways (colored airways) are predicated solely on L/MF navigation aids and are depicted

in brown on aeronautical charts and are identified by color name and number (e.g., Amber One). Green and Red

airways are plotted east and west. Amber and Blue airways are plotted north and south.

(c) The use of TSO−C145 (as revised) or TSO−C146 (as revised) GPS/WAAS navigation systems is

allowed in Alaska as the only means of navigation on published air traffic service (ATS) routes, including those

Victor, T−Routes, and colored airway segments designated with a second minimum en route altitude (MEA)

depicted in blue and followed by the letter G at those lower altitudes. The altitudes so depicted are below the

minimum reception altitude (MRA) of the land −based navigation facility defining the route segment, and

guarantee standard en route obstacle clearance and two−way communications. Air carrier operators requiring

operations specifications are authorized to conduct operations on those routes in accordance with FAA

operations specifications.

2. The jet route system consists of jet routes established from 18,000 feet MSL to FL 450 inclusive.

En Route Procedures5−3−20

AIM2/20/251/22/26 AIM

(a) These routes are depicted on Enroute High Altitude Charts. Jet routes are depicted in black on

aeronautical charts and are identified by a “J” (Jet) followed by the airway number (e.g., J12). Jet routes, as VOR

airways, are predicated solely on VOR or VORTAC navigation facilities (except in Alaska).

NOTE−

Segments of jet routes in Alaska are based on L/MF navigation aids and are charted in brown color instead of black on en

route charts.

(b) With respect to position reporting, reporting points are designated for jet route systems. Flights using

jet routes will report over these points unless otherwise advised by ATC.

3. Area Navigation (RNA V) Routes.

(a) Published RNA V routes, including Q−routes, T−routes, and Y−routes, can be flight planned for use

by aircraft with RNA V capability, subject to any limitations or requirements noted on en route charts, in

applicable Advisory Circulars, NOTAMs, etc. RNA V routes are normally depicted in blue on aeronautical charts

and are identified by the letter “Q,” “T,” or “Y” followed by the airway number (for example, Q13, T205, and

Y280). Published RNA V routes are RNA V 2 except when specifically charted as RNA V 1. Unless otherwise

specified, these routes require system performance currently met by GPS, GPS/WAAS, or DME/DME/IRU

RNA V systems that satisfy the criteria discussed in AC 90−100A, U.S. Terminal and En Route Area Navigation

(RNA V) Operations.

(1) Q−routes are available for use by RNA V equipped aircraft between 18,000 feet MSL and FL 450

inclusive. Q−routes are depicted on Enroute High Altitude Charts.

NOTE−

Aircraft in Alaska may only operate on GNSS Q-routes with GPS (TSO-C129 (as revised) or TSO-C196 (as revised))

equipment while the aircraft remains in Air Traffic Control (ATC) radar surveillance or with GPS/WAAS which does not

require ATC radar surveillance.

(2) T−routes are available for use by GPS or GPS/WAAS equipped aircraft from 1,200 feet above the

surface (or in some instances higher) up to but not including 18,000 feet MSL. T−routes are depicted on Enroute

Low Altitude Charts.

NOTE−

Aircraft in Alaska may only operate on GNSS T-routes with GPS/WAAS (TSO-C145 (as revised) or TSO-C146 (as revised))

equipment.

(3) Y−routes generally run in U.S. offshore airspace, however operators can find some Y−routes over

southern Florida. Pilots must use GPS for navigation and meet RNA V 2 performance requirements for all flights

on Y− routes. Operators can find additional Y −route requirements in the U.S. Aeronautical Information

Publication (AIP), ENR 7.10, available on the FAA website.

(b) Unpublished RNA V routes are direct routes, based on area navigation capability, between waypoints

defined in terms of latitude/longitude coordinates, degree −distance fixes, or offsets from established

routes/airways at a specified distance and direction. Radar monitoring by ATC is required on all unpublished

RNA V routes, except for GNSS−equipped aircraft cleared via filed published waypoints recallable from the

aircraft’s navigation database.

(c) Magnetic Reference Bearing (MRB) is the published bearing between two waypoints on an

RNA V/GPS/GNSS route. The MRB is calculated by applying magnetic variation at the waypoint to the

calculated true course between two waypoints. The MRB enhances situational awareness by indicating a

reference bearing (no−wind heading) that a pilot should see on the compass/HSI/RMI, etc., when turning prior

to/over a waypoint en route to another waypoint. Pilots should use this bearing as a reference only, because their

RNA V/GPS/GNSS navigation system will fly the true course between the waypoints.

b. Operation above FL 450 may be conducted on a point-to-point basis. Navigational guidance is provided

on an area basis utilizing those facilities depicted on the enroute high altitude charts.

c. Radar Vectors. Controllers may vector aircraft within controlled airspace for separation purposes, noise

abatement considerations, when an operational advantage will be realized by the pilot or the controller, or when

En Route Procedures 5−3−21

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requested by the pilot. Vectors outside of controlled airspace will be provided only on pilot request. Pilots will

be advised as to what the vector is to achieve when the vector is controller initiated and will take the aircraft off

a previously assigned nonradar route. To the extent possible, aircraft operating on RNA V routes will be allowed

to remain on their own navigation.

d. When flying in Canadian airspace, pilots are cautioned to review Canadian Air Regulations.

1. Special attention should be given to the parts which differ from U.S. CFRs.

(a) The Canadian Airways Class B airspace restriction is an example. Class B airspace is all controlled

low level airspace above 12,500 feet MSL or the MEA, whichever is higher, within which only IFR and

controlled VFR flights are permitted. (Low level airspace means an airspace designated and defined as such in

the Designated Airspace Handbook.)

(b) Unless issued a VFR flight clearance by ATC, regardless of the weather conditions or the height of

the terrain, no person may operate an aircraft under VMC within Class B airspace.

(c) The requirement for entry into Class B airspace is a student pilot permit (under the guidance or control

of a flight instructor).

(d) VFR flight requires visual contact with the ground or water at all times.

2. Segments of VOR airways and high level routes in Canada are based on L/MF navigation aids and are

charted in brown color instead of blue on en route charts.

FIG 5−3−1

Adhering to Airways or Routes

5−3−5. Airway or Route Course Changes

a. Pilots of aircraft are required to adhere to airways or routes being flown. Special attention must be given

to this requirement during course changes. Each course change consists of variables that make the technique

applicable in each case a matter only the pilot can resolve. Some variables which must be considered are turn

En Route Procedures5−3−22

AIM2/20/251/22/26 AIM

radius, wind effect, airspeed, degree of turn, and cockpit instrumentation. An early turn, as illustrated below, is

one method of adhering to airways or routes. The use of any available cockpit instrumentation, such as Distance

Measuring Equipment, may be used by the pilot to lead the turn when making course changes. This is consistent

with the intent of 14 CFR section 91.181, which requires pilots to operate along the centerline of an airway and

along the direct course between navigational aids or fixes.

b. Turns which begin at or after fix passage may exceed airway or route boundaries. FIG 5−3−1 contains an

example flight track depicting this, together with an example of an early turn.

c. Without such actions as leading a turn, aircraft operating in excess of 290 knots true air speed (TAS) can

exceed the normal airway or route boundaries depending on the amount of course change required, wind

direction and velocity, the character of the turn fix (DME, overhead navigation aid, or intersection), and the

pilot’s technique in making a course change. For example, a flight operating at 17,000 feet MSL with a TAS of

400 knots, a 25 degree bank, and a course change of more than 40 degrees would exceed the width of the airway

or route; i.e., 4 nautical miles each side of centerline. However, in the airspace below 18,000 feet MSL, operations

in excess of 290 knots TAS are not prevalent and the provision of additional IFR separation in all course change

situations for the occasional aircraft making a turn in excess of 290 knots TAS creates an unacceptable waste of

airspace and imposes a penalty upon the preponderance of traffic which operate at low speeds. Consequently,

the FAA expects pilots to lead turns and take other actions they consider necessary during course changes to

adhere as closely as possible to the airways or route being flown.

5−3−6. Changeover Points (COPs)

a. COPs are prescribed for Federal airways, jet routes, area navigation routes, or other direct routes for which

an MEA is designated under 14 CFR part 95. The COP is a point along the route or airway segment between two

adjacent navigation facilities or waypoints where changeover in navigation guidance should occur. At this point,

the pilot should change navigation receiver frequency from the station behind the aircraft to the station ahead.

b. The COP is normally located midway between the navigation facilities for straight route segments, or at

the intersection of radials or courses forming a dogleg in the case of dogleg route segments. When the COP is

NOT located at the midway point, aeronautical charts will depict the COP location and give the mileage to the

radio aids.

c. COPs are established for the purpose of preventing loss of navigation guidance, to prevent frequency

interference from other facilities, and to prevent use of different facilities by different aircraft in the same

airspace. Pilots are urged to observe COPs to the fullest extent.

5−3−7. Minimum Turning Altitude (MTA)

Due to increased airspeeds at 10,000 ft MSL or above, the published minimum enroute altitude (MEA) may not

be sufficient for obstacle clearance when a turn is required over a fix, NAV AID, or waypoint. In these instances,

an expanded area in the vicinity of the turn point is examined to determine whether the published MEA is

sufficient for obstacle clearance. In some locations (normally mountainous), terrain/obstacles in the expanded

search area may necessitate a higher minimum altitude while conducting the turning maneuver. Turning fixes

requiring a higher minimum turning altitude (MTA) will be denoted on government charts by the minimum

crossing altitude (MCA) icon (“x” flag) and an accompanying note describing the MTA restriction. An MTA

restriction will normally consist of the air traffic service (ATS) route leading to the turn point, the ATS route

leading from the turn point, and the required altitude; e.g., MTA V330 E TO V520 W 16000. When an MTA is

applicable for the intended route of flight, pilots must ensure they are at or above the charted MTA not later than

the turn point and maintain at or above the MTA until joining the centerline of the ATS route following the turn

point. Once established on the centerline following the turning fix, the MEA/MOCA determines the minimum

altitude available for assignment. An MTA may also preclude the use of a specific altitude or a range of altitudes

during a turn. For example, the MTA may restrict the use of 10,000 through 11,000 ft MSL. In this case, any

altitude greater than 11,000 ft MSL is unrestricted , as are altitudes less than 10,000 ft MSL provided

MEA/MOCA requirements are satisfied.

En Route Procedures 5−3−23

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5−3−8. Holding

a. Whenever an aircraft is cleared to a fix other than the destination airport and delay is expected, it is the

responsibility of A TC to issue complete holding instructions (unless the pattern is charted), an EFC time and best

estimate of any additional en route/terminal delay.

NOTE−

Only those holding patterns depicted on U.S. government or commercially produced (meeting F AA requirements) low/high

altitude en route, and area or STAR charts should be used.

b. If the holding pattern is charted and the controller doesn’t issue complete holding instructions, the pilot is

expected to hold as depicted on the appropriate chart. When the pattern is charted on the assigned procedure or

route being flown, ATC may omit all holding instructions except the charted holding direction and the statement

AS PUBLISHED; for example, HOLD EAST AS PUBLISHED. ATC must always issue complete holding

instructions when pilots request them.

c. If no holding pattern is charted and holding instructions have not been issued, the pilot should ask ATC for

holding instructions prior to reaching the fix. This procedure will eliminate the possibility of an aircraft entering

a holding pattern other than that desired by ATC. If unable to obtain holding instructions prior to reaching the

fix (due to frequency congestion, stuck microphone, etc.), then enter a standard pattern on the course on which

the aircraft approached the fix and request further clearance as soon as possible. In this event, the altitude/flight

level of the aircraft at the clearance limit will be protected so that separation will be provided as required.

d. When an aircraft is 3 minutes or less from a clearance limit and a clearance beyond the fix has not been

received, the pilot is expected to start a speed reduction so that the aircraft will cross the fix, initially, at or below

the maximum holding airspeed.

e. When no delay is expected, the controller should issue a clearance beyond the fix as soon as possible and,

whenever possible, at least 5 minutes before the aircraft reaches the clearance limit.

f. Pilots should report to ATC the time and altitude/flight level at which the aircraft reaches the clearance limit

and report leaving the clearance limit.

NOTE−

In the event of two-way communications failure, pilots are required to comply with 14 CFR section 91.185.

g. When holding at a VOR station, pilots should begin the turn to the outbound leg at the time of the first

complete reversal of the to/from indicator.

h. Patterns at the most generally used holding fixes are depicted (charted) on U.S. Government or

commercially produced (meeting FAA requirements) Low or High Altitude En Route, Area, Departure

Procedure, and STAR Charts. Pilots are expected to hold in the pattern depicted unless specifically advised

otherwise by ATC.

NOTE−

Holding patterns that protect for a maximum holding airspeed other than the standard may be depicted by an icon, unless

otherwise depicted. The icon is a standard holding pattern symbol (racetrack) with the airspeed restriction shown in the

center . In other cases, the airspeed restriction will be depicted next to the standard holding pattern symbol.

REFERENCE−

AIM, Para 5−3−8 j2, Holding.

i. An ATC clearance requiring an aircraft to hold at a fix where the pattern is not charted will include the

following information: (See FIG 5−3−2.)

1. Direction of holding from the fix in terms of the eight cardinal compass points (i.e., N, NE, E, SE, etc.).

2. Holding fix (the fix may be omitted if included at the beginning of the transmission as the clearance limit).

3. Radial, course, bearing, airway or route on which the aircraft is to hold.

4. Leg length in miles if DME or RNA V is to be used (leg length will be specified in minutes on pilot request

or if the controller considers it necessary).

En Route Procedures5−3−24

AIM2/20/251/22/26 AIM

5. Direction of turn if left turns are to be made, the pilot requests, or the controller considers it necessary.

6. Time to expect further clearance and any pertinent additional delay information.

En Route Procedures 5−3−25

TYPICAL PROCEDURE ON AN ILS OUTER MARKER

EXAMPLES OF HOLDING

OM M M

RUNWAY

VOR

VOR

TYPICAL PROCEDURE AT INTERSECTION

OF VOR RADIALS

HOLDING COURSE

AWAY FROM NAVAID

HOLDING COURSE

TOWARD NAVAID

VORTAC

15 NM DME FIX 10 NM DME FIX

TYPICAL PROCEDURE AT DME FIX

AIM 2/20/253/15/077110.65R CHG 2AIM 1/22/26

FIG 5−3−2

Holding Patterns

EXA MPLES OF HOLDING

TYPICAL PROCEDURE ON AN ILS OUTER MARKER

L OM M M

RUNWAY

VOR

VOR

TYPICAL PROCEDURE AT INTERSECTION

OF VOR RADIALS

HOLDING COURSE HOLDING COURSE

TOWARD NAVAID AWAY FROM NAVAID

VORTAC

15 NM DME FIX 10 NM DME FIX

TY PICA L PROCEDURE AT DME FIX

En Route Procedures5−3−26

1/22/26 AIM

FIG 5−3−3

Holding Pattern Descriptive Terms

ABEAMABEAM

HOLDING SIDEHOLDING SIDE

OUTBOUNDOUTBOUND

INBOUNDINBOUND

AIM2/20/25

END

OUTBOUNDOUTBOUND

ENDFIX ENDFIX END

RECIPROCALRECIPROCAL

FIXFIX NONHOLDING SIDENONHOLDING SIDE HOLDINGHOLDING

COURSECOURSE

j. Holding pattern airspace protection is based on the following procedures.

1. Descriptive Terms.

(a) Standard Pattern. Right turns (See FIG 5−3−3.)

(b) Nonstandard Pattern. Left turns

2. Airspeeds.

(a) All aircraft may hold at the following altitudes and maximum holding airspeeds:

TBL 5−3−24

Altitude (MSL) Airspeed (KIAS)

MHA − 6,000’ 200

6,001’ − 14,000’ 230

14,001’ and above 265

NOTE−

These are the maximum indicated air speeds applicable to all holding.

(b) The following are exceptions to the maximum holding airspeeds:

(1) Holding patterns from 6,001’ to 14,000’ may be restricted to a maximum airspeed of 210 KIAS.

This nonstandard pattern will be depicted by an icon.

(2) Holding patterns may be restricted to a maximum speed. The speed restriction is depicted in

parenthesis inside the holding pattern on the chart: e.g., (175). The aircraft should be at or below the maximum

speed prior to initially crossing the holding fix to avoid exiting the protected airspace. Pilots unable to comply

with the maximum airspeed restriction should notify ATC.

(3) Holding patterns at USAF airfields only − 310 KIAS maximum, unless otherwise depicted.

(4) Holding patterns at Navy fields only − 230 KIAS maximum, unless otherwise depicted.

(5) All helicopter/power lift aircraft holding on a “COPTER” instrument procedure is predicated on

a minimum airspeed of 90 KIAS unless charted otherwise.

(6) When a climb−in hold is specified by a published procedure (for example, “Climb −in holding

pattern to depart XYZ VORTAC at or above 10,000.” or “All aircraft climb−in TRUCK holding pattern to cross

TRUCK Int at or above 11,500 before proceeding on course.”), additional obstacle protection area has been

provided to allow for greater airspeeds in the climb for those aircraft requiring them. A maximum airspeed of

En Route Procedures 5−3−27

AIM 2/20/253/15/077110.65R CHG 2AIM 1/22/26

310 KIAS is permitted in Climb−in−holding, unless a maximum holding airspeed is published, in which case that

maximum airspeed is applicable. The airspeed limitations in 14 CFR section 91.117, Aircraft Speed, still apply.

(c) The following phraseology may be used by an ATCS to advise a pilot of the maximum holding

airspeed for a holding pattern airspace area.

PHRASEOLOGY−

(AIRCRAFT IDENTIFICATION) (holding instructions, when needed) MAXIMUM HOLDING AIRSPEED IS (speed in

knots).

FIG 5−3−4

Holding Pattern Entry Procedures

3. Entry Procedures. Holding protected airspace is designed based in part on pilot compliance with the

three recommended holding pattern entry procedures discussed below. Deviations from these recommendations,

coupled with excessive airspeed crossing the holding fix, may in some cases result in the aircraft exceeding

holding protected airspace. (See FIG 5−3−4.)

(a) Parallel Procedure. When approaching the holding fix from anywhere in sector (a), the parallel

entry procedure would be to turn to a heading to parallel the holding course outbound on the nonholding side

for one minute, turn in the direction of the holding pattern through more than 180 degrees, and return to the

holding fix or intercept the holding course inbound.

(b) Teardrop Procedure. When approaching the holding fix from anywhere in sector (b), the teardrop

entry procedure would be to fly to the fix, turn outbound to a heading for a 30 degree teardrop entry within the

pattern (on the holding side) for a period of one minute, then turn in the direction of the holding pattern to intercept

the inbound holding course.

(c) Direct Entry Procedure. When approaching the holding fix from anywhere in sector (c), the direct

entry procedure would be to fly directly to the fix and turn to follow the holding pattern.

(d) While other entry procedures may enable the aircraft to enter the holding pattern and remain within

protected airspace, the parallel, teardrop and direct entries are the procedures for entry and holding recommended

by the FAA, and were derived as part of the development of the size and shape of the obstacle protection areas

for holding.

(e) Nonstandard Holding Pattern. Fix end and outbound end turns are made to the left. Entry

procedures to a nonstandard pattern are oriented in relation to the 70 degree line on the holding side just as in

the standard pattern.

En Route Procedures5−3−28

AIM2/20/251/22/26 AIM

4. Timing.

(a) Inbound Leg.

(1) At or below 14,000 feet MSL: 1 minute.

(2) Above 14,000 feet MSL: 11/2 minutes.

NOTE−

The initial outbound leg should be flown for 1 minute or 1 1/2 minutes (appropriate to altitude). Timing for subsequent

outbound legs should be adjusted, as necessary, to achieve proper inbound leg time. Pilots may use any navigational means

available; i.e., DME, RNAV , etc., to ensure the appropriate inbound leg times.

(b) Outbound leg timing begins over/abeam the fix, whichever occurs later. If the abeam position cannot

be determined, start timing when turn to outbound is completed.

5. Distance Measuring Equipment (DME)/ GPS Along−Track Distance (ATD). DME/GPS holding is

subject to the same entry and holding procedures except that distances (nautical miles) are used in lieu of time

values. The outbound course of the DME/GPS holding pattern is called the outbound leg of the pattern. The

controller or the instrument approach procedure chart will specify the length of the outbound leg. The end of the

outbound leg is determined by the DME or ATD readout. The holding fix on conventional procedures, or

controller defined holding based on a conventional navigation aid with DME, is a specified course or radial and

distances are from the DME station for both the inbound and outbound ends of the holding pattern. When flying

published GPS overlay or stand alone procedures with distance specified, the holding fix will be a waypoint in

the database and the end of the outbound leg will be determined by the ATD. Some GPS overlay and early stand

alone procedures may have timing specified. (See FIG 5−3−5, FIG 5−3−6 and FIG 5− 3−7.) See paragraph

1−1−17, Global Positioning System (GPS), for requirements and restriction on using GPS for IFR operations.

FIG 5−3−5

Inbound Toward NA V AID

NOTE−

When the inbound course is toward the NAVAID, the fix distance is 10 NM, and the leg length is 5 NM, then the end of the

outbound leg will be reached when the DME reads 15 NM.

FIG 5−3−6

Inbound Leg Away from NA V AID

NOTE−

When the inbound course is away from the NAVAID and the fix distance is 28 NM, and the leg length is 8 NM, then the end

of the outbound leg will be reached when the DME reads 20 NM.

En Route Procedures 5−3−29