Figure 8-1. The pilot in command is responsible for the airworthy
condition of the aircraft and using checklists to ensure proper
inspection of the helicopter prior to flight.
Preflight
Before any flight, ensure the helicopter is airworthy by
inspecting it according to the rotorcraft flight manual (RFM),
pilot’s operating handbook (POH), or other information
supplied either by the operator or the manufacturer.
Remember that it is the responsibility of the pilot in command
(PIC) to ensure the aircraft is in an airworthy condition.
In preparation for flight, the use of a checklist is important
so that no item is overlooked. [Figure 8-1] Follow the
manufacturer’s suggested outline for both the inside and
outside inspection. This ensures that all the items the
manufacturer feels are important are checked. If supplemental
equipment has been added to the helicopter, these procedures
should be included on the checklist as well.
Minimum Equipment Lists (MELs) and Operations
with Inoperative Equipment
Title 14 of the Code of Federal Regulations (14 CFR) requires
that all aircraft instruments and installed equipment be
operative prior to each departure. However, when the Federal
Aviation Administration (FAA) adopted the minimum
equipment list (MEL) concept for 14 CFR part 91 operations,
flights were allowed with inoperative items, as long as the
inoperative items were determined to be nonessential for safe
flight. At the same time, it allowed part 91 operators, without
an MEL, to defer repairs on nonessential equipment within
the guidelines of part 91.
There are two primary methods of deferring maintenance
on rotorcraft operating under part 91. They are the deferral
provision of 14 CFR part 91, section 91.213(d) and an FAA-
approved MEL.
The deferral provision of 14 CFR section 91.213(d) is
widely used by most pilot/operators. Its popularity is due
to simplicity and minimal paperwork. When inoperative
equipment is found during preflight or prior to departure, the
decision should be to cancel the flight, obtain maintenance
prior to flight, determine if the flight can be made under the
limitations imposed by the defective equipment, or to defer
the item or equipment.
Maintenance deferrals are not used for in-flight discrepancies.
The manufacturer’s RFM/POH procedures are to be used in
those situations. The discussion that follows is an example of
a pilot who wishes to defer maintenance that would ordinarily
be required prior to flight.
If able to use the deferral provision of 14 CFR section
91.213(d), the pilot determines whether the inoperative
equipment is required by type design or 14 CFR. If the
inoperative item is not required, and the helicopter can be
safely operated without it, the deferral may be made. The
inoperative item shall be deactivated or removed and an
INOPERATIVE placard placed near the appropriate switch,
control, or indicator. If deactivation or removal involves
maintenance (removal always does), it must be accomplished
by certificated maintenance personnel.
For example, if the position lights (installed equipment) were
discovered to be inoperative prior to a daytime flight, the pilot
would follow the requirements of 14 CFR section 91.213(d).
The pilot must then decide if the flight can be accomplished
prior to night, when the lights will be needed.
The deactivation may be a process as simple as the pilot
positioning a circuit breaker to the off position, or as complex
as rendering instruments or equipment totally inoperable.
Complex maintenance tasks require a certificated and
appropriately rated maintenance person to perform the
deactivation. In all cases, the item or equipment must be
placarded INOPERATIVE.
When an operator requests an MEL, and a Letter of
Authorization (LOA) is issued by the FAA, then the use
of the MEL becomes mandatory for that helicopter. All
maintenance deferrals must be accomplished in accordance
with the terms and conditions of the MEL and the operator-
generated procedures document.
Figure 8-2. Exercise extreme caution when hovering near buildings
or other aircraft.
The use of an MEL for rotorcraft operated under part 91 also
allows for the deferral of inoperative items or equipment. The
primary guidance becomes the FAA-approved MEL issued
to that specific operator and N-numbered helicopter.
The FAA has developed master minimum equipment lists
(MMELs) for rotorcraft in current use. Upon written request
by a rotorcraft operator, the local FAA Flight Standards
District Office (FSDO) may issue the appropriate make and
model MMEL, along with an LOA, and the preamble. The
operator then develops operations and maintenance (O&M)
procedures from the MMEL. This MMEL with O&M
procedures now becomes the operator’s MEL. The MEL,
LOA, preamble, and procedures document developed by the
operator must be on board the helicopter when it is operated.
The FAA considers an approved MEL to be a supplemental
type certificate (STC) issued to an aircraft by serial number
and registration number. It therefore becomes the authority
to operate that aircraft in a condition other than originally
type certificated.
With an approved MEL, if the position lights were discovered
inoperative prior to a daytime flight, the pilot would make
an entry in the maintenance record or discrepancy record
provided for that purpose. The item is then either repaired or
deferred in accordance with the MEL. Upon confirming that
daytime flight with inoperative position lights is acceptable in
accordance with the provisions of the MEL, the pilot would
leave the position lights switch off, open the circuit breaker
(or whatever action is called for in the procedures document),
and placard the position light switch as INOPERATIVE.
There are exceptions to the use of the MEL for deferral. For
example, should a component fail that is not listed in the
MEL as deferrable (the rotor tachometer, engine tachometer,
or cyclic trim, for example), then repairs are required to be
performed prior to departure. If maintenance or parts are not
readily available at that location, a special flight permit can
be obtained from the nearest FSDO. This permit allows the
helicopter to be flown to another location for maintenance.
This allows an aircraft that may not currently meet applicable
airworthiness requirements, but is capable of safe flight, to
be operated under the restrictive special terms and conditions
attached to the special flight permit.
Deferral of maintenance is not to be taken lightly, and due
consideration should be given to the effect an inoperative
component may have on the operation of a helicopter,
particularly if other items are inoperative. Further information
regarding MELs and operations with inoperative equipment
can be found in AC 9 1-67, Minimum Equipment Requirements
for General Aviation Operations Under FAR Part 91.
Engine Start and Rotor Engagement
During the engine start, rotor engagement, and systems
ground check, use the manufacturer’s checklists. If a problem
arises, have it checked before continuing. Prior to performing
these tasks, however, make sure the area around and above
the helicopter is clear of personnel and equipment. Position
the rotor blades so that they are not aligned with the fuselage.
This may prevent the engine from being started with the
blades still fastened. For a two-bladed rotor system, position
the blades so that they are perpendicular to the fuselage
and easily seen from the cockpit. Helicopters are safe and
efficient flying machines as long as they are operated within
the parameters established by the manufacturer.
Rotor Safety Considerations
The exposed nature of the main and tail rotors deserves
special caution. Exercise extreme care when taxiing near
hangars or obstructions since the distance between the
rotor blade tips and obstructions is very difficult to judge.
[Figure 8-2] In addition, the tail rotor of some helicopters
cannot be seen from the cabin. Therefore, when hovering
backward or turning in those helicopters, allow plenty of
room for tail rotor clearance. It is a good practice to glance
over your shoulder to maintain this clearance
Another rotor safety consideration is the thrust a helicopter
generates. The main rotor system is capable of blowing sand,
dust, snow, ice, and water at high velocities for a significant
distance causing injury to nearby people and damage to
buildings, automobiles, and other aircraft. Loose snow, sand,
or soil can severely reduce visibility and obscure outside visual
references. There is also the possibility of sand and snow
being ingested into the engine intake, which can overwhelm
filters and cutoff air to the engine or allow unfiltered air into
the engine, leading to premature failure. Any airborne debris
near the helicopter can be ingested into the engine air intake
or struck by the main and tail rotor blades.
Aircraft Servicing
The helicopter rotor blades are usually stopped, and both the
aircraft and the refueling unit properly grounded prior to any
refueling operation. The pilot should ensure that the proper
grade of fuel and the proper additives, when required, are
being dispensed.
Refueling of a turbine aircraft while the blades are turning,
known as “hot refueling,” may be practical for certain types
of operation. However, this can be hazardous if not properly
conducted. Pilots should remain at the flight controls; and
refueling personnel should be knowledgeable about the
proper refueling procedures and properly briefed for specific
helicopter makes and models.
The pilot may need to train the refueling personnel on
proper hot refueling procedures for that specific helicopter.
The pilot should explain communication signs or calls,
normal servicing procedures, and emergency procedures as
a minimum. At all times during the refueling process, the
pilot should remain vigilant and ready to immediately shut
down the engine(s) and egress the aircraft. Several accidents
have occurred due to hot refueling performed by improperly
trained personnel.
Refueling units should be positioned to ensure adequate
rotor blade clearance. Persons not involved with the
refueling operation should keep clear of the area. Smoking
must be prohibited in and around the aircraft during all
refueling operations.
If operations dictate that the pilot must leave the helicopter
during refueling operations, the throttle should be rolled
back to flight idle and flight control friction firmly applied to
prevent uncommanded control movements. The pilot should
be thoroughly trained on setting the controls and egressing/
ingressing the helicopter.
Safety in and Around Helicopters
People have been injured, some fatally, in helicopter accidents
that would not have occurred had they been informed of the
proper method of boarding or deplaning. [Figure 8-3] A
properly briefed passenger should never be endangered by
a spinning rotor. The simplest method of avoiding accidents
of this sort is to stop the rotors before passengers are boarded
or allowed to depart. Because this action is not always
practicable, and to realize the vast and unique capabilities
of the helicopter, it is often necessary to take on passengers
or have them exit the helicopter while the engine and rotors
are turning. To avoid accidents, it is essential that all persons
associated with helicopter operations, including passengers,
be made aware of all possible hazards and instructed how
those hazards can be avoided.
Ramp Attendants and Aircraft Servicing Personnel
These personnel should be instructed as to their specific
duties and the proper method of fulfilling them. In addition,
the ramp attendant should be taught to:
1. Keep passengers and unauthorized persons out of the
helicopter landing and takeoff area.
2. Brief passengers on the best way to approach and
board a helicopter with its rotors turning.
Persons directly involved with boarding or deplaning
passengers, aircraft servicing, rigging, or hooking up external
loads, etc., should be instructed as to their duties. It would be
difficult, if not impossible, to cover each and every type of
operation related to helicopters. A few of the more obvious
and common ones are covered below.
Passengers
Passengers increase the responsibility, workload, and risk for
the pilot. The workload and distractions seem magnified to
inexperienced pilots while they are developing confidence and
ability to operate in the aviation environment. Inexperienced
pilots should consider building up their passenger carrying
experience while remaining in good flying conditions and
in a familiar area.
All persons boarding a helicopter while its rotors are turning
should be briefed on the safest means of doing so. The pilot
in command (PIC) should always brief the passengers prior
to engine start to ensure complete understanding of all
procedures. The exact procedures may vary slightly from
one helicopter model to another, but the following should
suffice as a generic guide.
When boarding—
1. Stay away from the rear of the helicopter.
2. Approach or leave the helicopter in a crouching manner.
3. Approach from the side of the helicopter but never
out of the pilot’s line of vision. Certain rotor system
designs allow for rotor blades to pass closer to the
ground towards the front of the helicopter. For that
reason, it is generally accepted for personnel to
approach from the side of the helicopter. Helicopters
designed to be loaded from the rear require personnel
to exercise extreme caution due to tailrotor hazards.
4. Carry tools horizontally, below waist level—never
upright or over the shoulder.
5. Hold firmly onto hats and loose articles.
6. Never reach up or dart after a hat or other object that
might be blown off or away.
7. Protect eyes by shielding them with a hand or by
Approaching or Leaving a Helicopter
SAFETY AROUND HELICOPTERS
Do not approach or leave without the pilot’s visual
acknowledgment. Keep in pilot’s field of vision at all times.
Observe helicopter safety zones (see diagram at right).
If blinded by swirling dust or grit, STOP—crouch lower,
or sit down and await assistance.
On sloping ground, always approach or leave on the
downslope side for maximum rotor clearance.
If disembarking while helicopter is at the hover, get out and
off in a smooth unhurried manner.
Do not approach or leave a helicopter when the engine and
rotors are running down or starting up.
Carry tools, etc., horizontally below waist level—never upright
or on the shoulder.
Proceed in a crouching manner for extra rotor clearance.
Hold onto hat unless chin straps are used. NEVER reach
up or chase after a hat or other articles that blow away.
PREFERRED
ACCEPTABLE
PROHIBITED
PROHIBITED
ACCEPTABLE
Figure 8-3. Safety procedures for approaching or leaving a helicopter.
squinting.
8. If suddenly blinded by dust or a blowing object, stop
and crouch lower; better yet, sit down and wait for help.
9. Never grope or feel your way toward or away from
the helicopter.
10. Protect hearing by wearing earplugs or earmuffs.
Since few helicopters carry cabin attendants, the pilot must
conduct the pretakeoff and prelanding briefings, usually
before takeoff due to noise and cockpit layout. The type
of operation dictates what sort of briefing is necessary. All
briefings should include the following:
1. Passengers should be briefed and understand the proper
use of seatbelts, doors, and headsets/intercom system.
2. The safe entry and exit paths (away from the tail rotor
and within the pilot’s view).
3. If possible, remove front passenger flight controls and
ensure all passenger personal items, such as cameras
and mobile phones are secure.
4. For over water flights, the location and use of flotation
gear and other survival equipment that are onboard.
Pilot instructions should include how and when to exit
the helicopter should ditching or a water landing occur.
5. For flights over rough or isolated terrain, the pilot
should brief all occupants regarding the location of
maps and survival equipment.
6. Passengers should be informed as to what actions and
precautions to take in the event of an emergency, such
as the body position for best spinal protection against
a high vertical impact (erect with back firmly against
the seat back); and when and how to exit. Ensure
that passengers are aware of the location of the fire
extinguisher, survival equipment and, if equipped,
how to use and locate the Emergency Position
Indicator Radio Beacon (EPIRB).
When passengers are approaching or leaving a helicopter
that is sitting on a slope with the rotors turning, they should
approach and depart downhill. This affords the greatest
distance between the rotor blades and the ground. If this
involves walking around the helicopter, they should always
go around the front—never the rear.
Pilot at the Flight Controls
Many helicopter operators have been lured into a “quick
turnaround” ground operation to avoid delays at airport
terminals and to minimize stop/start cycles of the engine.
As part of this quick turn-around, the pilot might leave
the cockpit with the engine and rotors turning. Such an
operation can be extremely hazardous if a gust of wind
disturbs the rotor disk, or the collective flight control
moves causing lift to be generated by the rotor system.
Either occurrence may cause the helicopter to roll or pitch,
resulting in a rotor blade striking the tail boom or the
ground. Good operating procedures dictate that, generally,
pilots remain at the flight controls whenever the engine is
running, and the rotors are turning.
If operations require the pilot to leave the cockpit to refuel,
the throttle should be rolled back to flight idle and all
controls firmly frictioned to prevent uncommanded control
movements. The pilot should be well trained on setting
controls and exiting the cockpit without disturbing the flight
or power controls.
After Landing and Securing
When the flight is terminated, park the helicopter where
it does not interfere with other aircraft and is not a hazard
to people during shutdown. For many helicopters, it is
advantageous to land with the wind coming from the right
over the tail boom (counterrotating blades). This tends to
lift the blades over the tail boom but lowers the blades in
front of the helicopter. This action decreases the likelihood
of a main rotor strike to the tail boom due to gusty winds.
Rotor downwash can cause damage to other aircraft in close
proximity, and spectators may not realize the danger or see the
rotors turning. Passengers should remain in the helicopter with
their seats belts secured until the rotors have stopped turning.
During the shutdown and postflight inspection, follow the
manufacturer’s checklist. Any discrepancies should be noted
and, if necessary, reported to maintenance personnel.
Chapter Summary
This chapter explained the importance of preflight and
safety when conducting helicopter ground operations. Proper
procedures for engine run-up, refueling, and ground safety
were detailed and the responsibilities of the pilot when
maintenance issues occur before flight.
Introduction
From the previous chapters, it should be apparent that no
two helicopters perform the same way. Even when flying
the same model of helicopter, wind, temperature, humidity,
weight, and equipment make it difficult to predict just how
the helicopter will perform. Therefore, this chapter presents
the basic flight maneuvers in a way that would apply to
the majority of helicopters. In most cases, the techniques
described apply to small training helicopters with:
• A single, main rotor rotating in a counterclock wise
direction (looking downward on the rotor).
• An antitorque system.
Basic Flight Maneuvers
Chapter 9
Where a technique differs, it is noted. For example, a power
increase on a helicopter with a clockwise rotor system
requires right antitorque pedal pressure instead of left pedal
pressure. In many cases, the terminology “apply proper pedal
pressure” is used to indicate both types of rotor systems.
However, when discussing throt tle coordination to maintain
proper rotations per minute (rpm), there is no differentiation
between those helicopters with a gov ernor and those without.
In a sense, the governor is doing the work for you. In addition,
instead of using the terms “collective pitch control” and
“cyclic pitch control” throughout the chapter, these controls
are referred to as just “collective” and “cyclic.”
Because helicopter performance varies with weather
conditions and aircraft loading, specific nose attitudes and
power settings are not detailed in this handbook. In addition,
this chapter does not detail every attitude of a helicopter in
the various flight maneuvers, nor every move that must be
made in order to perform a given maneuver.
When a maneuver is presented, there is a brief description,
followed by the technique to accomplish the maneuver. In
most cases, there is a list of common errors at the end of the
discussion.
The Four Fundamentals
There are four fundamentals of flight upon which all
maneuvers are based: straight-and-level flight, turns, climbs,
and descents. All controlled flight maneuvers consist of one
or more of these four fundamentals of flight. If a student pilot
is able to perform these maneuvers well, and the student’s
proficiency is based on accurate “feel” and control analysis
rather than mechanical movements, the ability to perform
any assigned maneuver is only a matter of obtaining a clear
visual and mental conception of it. The flight instructor must
impart a good knowledge of these basic elements to the
student and must combine them and plan their practice so that
proper performance of each is instinctive without conscious
effort. The importance of this to the success of flight training
cannot be overemphasized. As the student progresses to
more complex maneuvers, discounting any difficulties in
visualizing the maneuvers, most student difficulties are
caused by a lack of training, practice, or understanding of the
principles of one or more of these fundamentals.
Guidelines
Good practices to follow during maneuvering flight include:
1. Move the cyclic only as fast as trim, torque, and rotor
speed can be maintained. When entering a maneuver
and the trim, rotor, or torque reacts quicker than
anticipated, pilot limitations have been exceeded. If
continued, an aircraft limitation will be exceeded.
Perform the maneuver with less intensity until all
aspects of the machine can be controlled. The pilot
must be aware of the sensitivity of the flight controls
due to the high speed of the main rotor.
2. Anticipate changes in aircraft performance due to
loading or environmental condition. The normal
collective increase to check rotor speed at sea level
standard (SLS) may not be sufficient at 4,000 feet
pressure altitude (PA) and 95 °F.
3. The following flight characteristics may be expected
during maneuvering flight and will be discussed and
demonstrated by your Flight Instructor:
• Left turns, torque increases (more antitorque).
This applies to most helicopters, but not all.
• Right turns, torque decreases (less antitorque).
This applies to most helicopters, but not all.
• Application of aft cyclic, torque decreases and
rotor speed increases.
• Application of forward cyclic (especially when
immediately following aft cyclic application),
torque increases and rotor speed decreases.
• Always leave a way out.
• Know where the winds are.
• Engine failures can occur during power changes
and cruise flight. One possible cause of engine
failure during cruise flight can be attributed to the
pilot ignoring carburetor air temperatures, which
could lead to carburetor icing and, subsequently,
engine failure.
• Crew coordination is critical. Everyone needs
to be fully aware of what is going on, and each
crewmember has a specific duty.
• In steep turns, the nose drops. In most cases,
energy (airspeed) must be traded to maintain
altitude as the required excess engine power may
not be available (to maintain airspeed in a 2G/60°
turn, rotor thrust/engine power must increase by
100 percent). Failure to anticipate this at low
altitude endangers the crew and passengers.
The rate of pitch change is proportional to gross
weight and density altitude.
• Normal helicopter landings usually require high
power settings, with terminations to a hover
requiring the highest power setting.
• The cyclic position relative to the horizon
determines the helicopter’s travel and attitude.
A O M
CLUTCH MR
TEMP
MR
CHIP
STARTER
ON
TR
CHIP
lOW
FUEL
LOW
RPM
26 26
FUEL
245 II5
OBS
21 15
NAV
GS
VERTICAL SPEED
100 FEET PER MINUTE
UP
DOWN
2I
I2 6
2 MIN TURN
DC ELEC
L R
30.0
29.929.8
I00 FEET
CALIBRATED
TO
20,000 FEET
ALT
20 20
I0 I0
I0 I0
20 20
TESTSTBY PWR
IN Hg
ALg.
MANFOLD
PRESS
20 30
0 10
MPH
KNOTS
90 80 70
E R
%RPM
Figure 9-1. Maintain straight-and-level flight by adjusting the rotor
tip-path plane forward but adjusting the collective as necessary to
maintain a constant airspeed and altitude. The natural horizon line
can be used as an aid in maintaining straight-and-level flight. If
the horizon line begins to rise, slight power may be required or the
nose of the helicopter may be too low. If the horizon line is slowly
dropping, some power may need to be taken out or the nose of the
helicopter may be too high, requiring a cyclic adjustment.
Straight-and-Level Flight
Straight-and-level flight is flight in which constant altitude
and heading are maintained. The attitude of the rotor disk
relative to the horizon determines the airspeed. The horizontal
stabilizer design determines the helicopter’s attitude when
stabilized at an airspeed and altitude. Altitude is primarily
controlled by use of the collective.
Technique
To maintain forward flight, the rotor tip-path plane must
be tilted forward to obtain the necessary horizontal thrust
component from the main rotor. By doing this, it causes the
nose of the helicopter to lower which in turn will cause the
airspeed to increase. In order to counteract this, the pilot
must find the correct power setting to maintain level flight by
adjusting the collective. [Figure 9-1] The horizontal stabilizer
aids in trimming the helicopter about its transverse, horizontal
axis, and reduces the amount of nose tuck that would occur.
On several helicopters, it is designed as a negative lift airfoil,
which produces a lifting force in a downward direction.
When in straight-and-level flight, any increase in the
collective, while holding airspeed constant, causes the
helicopter to climb. A decrease in the collective, while holding
airspeed constant, causes the helicopter to descend. A change
in the collective requires a coordi nated change of the throttle
to maintain a constant rpm. Additionally, the antitorque pedals
need to keep the helicopter in trim around the vertical axis.
To increase airspeed in straight-and-level flight, apply
forward pressure on the cyclic and raise the collective as
necessary to maintain altitude. To decrease airspeed, apply
rearward pressure on the cyclic and lower the collective, as
necessary, to maintain altitude.
Although the cyclic is sensitive, there is a slight delay in
control reaction, and it is necessary to antici pate actual
movement of the helicopter. When making cyclic inputs to
control the altitude or airspeed of a hel icopter, take care not
to overcontrol. If the nose of the helicopter rises above the
level-flight attitude, apply forward pressure to the cyclic to
bring the nose down. If this correction is held too long, the
nose drops too low. Since the helicopter continues to change
attitude momentarily after the controls reach neutral, return
the cyclic to neutral slightly before the desired attitude is
reached. This principle holds true for any cyclic input.
Since helicopters are not very stable, but are inherently very
controllable, if a gust or turbulence causes the nose to drop,
the nose tends to continue to drop instead of returning to a
straight-and-level attitude as it would on a fixed-wing aircraft.
Therefore, a pilot must remain alert and fly the helicop ter
at all times.
Common Errors
1. Failure to trim the helicopter properly, tending to hold
antitorque pedal pressure and opposite cyclic. This is
commonly called cross-controlling.
2. Failure to maintain desired airspeed.
3. Failure to hold proper control position to main tain
desired ground track.
4. Failure to allow helicopter to stabilize at new airspeed.
Turns
A turn is a maneuver used to change the heading of the
helicopter. The aerodynamics of a turn were previously
discussed in Chapter 2, Aerodynamics of Flight.
Technique
Before beginning any turn, the area in the direction of the
turn must be cleared not only at the helicopter’s alti tude, but
also above and below. To enter a turn from straight-and-level
flight, apply sideward pressure on the cyclic in the direction
the turn is to be made. This is the only control movement
needed to start the turn. Do not use the pedals to assist the
turn. Use the pedals only to compensate for torque to keep
the helicopter in trim around the vertical axis. [Figure 9-2]
Keeping the fuselage in the correct streamlined position
around the vertical axis facilitates the helicopter flying
forward with the least drag. Trim is indicated by a yaw string
in the center, or a centered ball on a turn and slip indicator. A
yaw string (also referred to as a slip string) is a tool used to
indicate slip or skid during flight. It is simply a string attached
to the nose or canopy of an aircraft so that it is visible to the
pilot during flight. The string measures sideslip and offers
a visual cue to the pilot in order to make yaw corrections.
Inertia
HCL
Figure 9-2. During a level, coordinated turn, the rate of turn
is commensurate with the angle of bank used, and inertia and
horizontal component of lift (HCL) are equal.
Skid
Inertia
HCL
Slip
Inertia
HCL
Figure 9-3. During a slip, the rate of turn is too low for the angle
of bank used, and the horizontal component of lift (HCL) exceeds
inertia.
Figure 9-4. During a skid, the rate of turn is too great for the
angle of bank used, and inertia exceeds the horizontal component
of lift (HCL).
How fast the helicopter banks depends on how much lateral
cyclic pressure is applied. How far the helicop ter banks (the
steepness of the bank) depends on how long the cyclic is
displaced. After establishing the proper bank angle, return
the cyclic toward the neutral position. When the bank is
established, returning the cyclic to neutral (or holding it
inclined relative to the horizon) will maintain the helicopter
at that bank angle. Increase the collective and throttle to
maintain altitude and rpm. As the torque increases, increase
the proper antitorque pedal pressure to maintain longi tudinal
trim. Depending on the degree of bank, addi tional forward
cyclic pressure may be required to maintain airspeed.
Rolling out of the turn to straight-and-level flight is the same
as the entry into the turn, except that pressure on the cyclic
is applied in the opposite direction. Since the helicopter
continues to turn as long as there is any bank, start the rollout
before reaching the desired heading.
The discussion on level turns is equally applicable to making
turns while climbing or descending. The only difference is
that the helicopter is in a climbing or descending attitude
rather than that of level flight. If a so-called simultaneous
entry (entering a turn while, at the same time, climbing or
descending) is desired, merely combine the techniques of
both maneuvers—climb or descent entry and turn entry.
When recovering from a climbing or descending turn, the
desired heading and altitude are rarely reached at the same
time. If the heading is reached first, stop the turn and maintain
the climb or descent until reaching the desired altitude. On the
other hand, if the altitude is reached first, establish the level
flight attitude and continue the turn to the desired heading.
Slips
A slip occurs when the helicopter slides sideways toward the
center of the turn. [Figure 9-3] It is caused by an insufficient
amount of antitorque pedal in the direction of the turn,
or too much in the direction oppo site the turn, in relation
to the amount of power used. In other words, if you hold
improper antitorque pedal pres sure, which keeps the nose
from following the turn, the helicopter slips sideways toward
the center of the turn.
Skids
A skid occurs when the helicopter slides sideways away from
the center of the turn. [Figure 9-4] It is caused by too much
antitorque pedal pressure in the direction of the turn, or by
too little in the direction opposite the turn in relation to the
amount of power used. If the helicopter is forced to turn faster
with increased pedal pressure instead of by increasing the
degree of the bank, it skids sideways away from the center
of the turn instead of flying in its normal curved path.
In summary, a skid occurs when the rate of turn is too great
for the amount of bank being used, and a slip occurs when
the rate of turn is too low for the amount of bank being used.
[Figure 9-5]
30.0
29.929.8
I00 FEET
CALIBRATED
TO
20,000 FEET
ALT
OFF
GO
NAV
NET AVG
PULL
PUSH
HW
DIST
ALT
PUSH
4 6
-2 -4
Acceleration
G UNITS
N 30 60 E 120 150
STEER
FOR
S 210 240 W 300 330
STEER
RADIO
FOR
ON ON
120 80
knots
knotswinter
50 60 70 80 90 100
knots SALTO
+
−
PWR
FNCN
SEL
VOL BATT
KNOTS
PUSH
30.0
29.929.8
I00 FEET
CALIBRATED
TO
20,000 FEET
ALT
OFF
GO
NAV
NET AVG
PULL
PUSH
HW
DIST
ALT
PUSH
4 6
-2 -4
Acceleration
G UNITS
N 30 60 E 120 150
STEER
FOR
S 210 240 W 300 330
STEER
RADIO
FOR
ON ON
120 80
knots
knotswinter
50 60 70 80 90 100
knots SALTO
+
−
PWR
FNCN
SEL
VOL BATT
KNOTS
PUSH
30.0
29.929.8
I00 FEET
CALIBRATED
TO
20,000 FEET
ALT
OFF
GO
NAV
NET AVG
PULL
PUSH
HW
DIST
ALT
PUSH
4 6
-2 -4
Acceleration
G UNITS
N 30 60 E 120 150
STEER
FOR
S 210 240 W 300 330
STEER
RADIO
FOR
ON ON
120 80
knots
knotswinter
50 60 70 80 90 100
knots SALTO
+
−
PWR
FNCN
SEL
VOL BATT
KNOTS
PUSH
Slip
Skid
Coordinated
Yaw string
Yaw string
Yaw string
Figure 9-5. Cockpit view of a slip and skid.
Normal Climb
The entry into a climb from a hover has already been described
in the Normal Takeoff from a Hover subsection; there fore,
this discussion is limited to a climb entry from cruising flight.
Technique
To enter a climb in a helicopter while maintaining airspeed,
the first actions are increasing the collective and throttle,
and adjusting the pedals as necessary to maintain a centered
ball in the slip/skid indicator. Moving the collective up
requires a slight aft movement of the cyclic to direct all
of the increased power into lift and maintain the airspeed.
Remember, a helicopter can climb with the nose down and
descend with the nose up. Helicopter attitude changes mainly
reflect acceleration or deceleration, not climb or descent.
Therefore, the climb attitude is approximately the same as
level flight in a stable climb, depending on the aircraft’s
horizontal stabilizer design.
If the pilot wishes to climb faster, with a decreased airspeed,
then the climb can be initiated with aft cyclic. Depending
on initial or entry airspeed for the climb, the climb can be
accomplished without increasing the collective, if a much
slower airspeed is acceptable. However, as the airspeed
decreases, the airflow over the vertical fin decreases
necessitating more antitorque (left) pedal application.
To level off from a climb, start adjusting the attitude to the
level flight attitude a few feet prior to reaching the desired
altitude. The amount of lead depends on the rate of climb at
the time of level-off (the higher the rate of climb, the more
the lead). Generally, the lead is 10 percent of the climb rate.
For example, if the climb rate is 500 feet per minute (fpm),
you should lead the level-off by 50 feet.
To begin the level-off, apply forward cyclic to adjust and
maintain a level flight attitude, which can be slightly nose
low. Maintain climb power until the airspeed approaches the
desired cruising airspeed, then lower the collective to obtain
cruising power and adjust the throttle to obtain and maintain
cruising rpm. Throughout the level-off, maintain longitudinal
trim with the antitorque pedals.
Common Errors
1. Failure to maintain proper power and airspeed.
2. Holding too much or too little antitorque pedal.
3. In the level-off, decreasing power before adjusting the
nose to cruising attitude.
Normal Descent
A normal descent is a maneuver in which the helicop ter loses
altitude at a controlled rate in a controlled attitude.
Technique
To establish a normal descent from straight-and-level flight
at cruising airspeed, lower the collective to obtain proper
power, adjust the throttle to maintain rpm, and increase
right antitorque pedal pressure to maintain heading in a
counterclockwise rotor system (or left pedal pressure in a
clockwise system). If cruising airspeed is the same as or
slightly above descending air speed, simultaneously apply
the necessary cyclic pressure to obtain the approximate
descending attitude. If the pilot wants to decelerate, the
cyclic must be moved aft. If the pilot desires to descend with
increased airspeed, then forward cyclic is all that is required if
airspeed remains under the limit. As the helicopter stabilizes
at any forward airspeed, the fuselage attitude will streamline
due to the airflow over the horizontal stabilizer. As the
airspeed changes, the airflow over the vertical stabilizer or
fin changes, so the pedals must be adjusted for trim.
The pilot should always remember that the total lift and thrust
vectoring is controlled by the cyclic. If a certain airspeed
is desired, it will require a certain amount of cyclic and
collective movement for level flight. If the cyclic is moved,
the thrust-versus-lift ratio is changed. Aft cyclic directs
more power to lift, and altitude increases. Forward cyclic
directs more power to thrust, and airspeed increases. If the
collective is not changed and there is a change only in cyclic,
the total thrust to lift ratio does not change: aft cyclic results
in a climb, and forward cyclic results in a descent with the
corresponding airspeed changes.
To level off from the descent, lead the desired altitude
by approximately 10 percent of the rate of descent. For
example, a 500-fpm rate of descent would require a 50-foot
lead. At this point, increase the collective to obtain cruising
power, adjust the throttle to maintain rpm, and increase left
antitorque pedal pressure to maintain heading (right pedal
pressure in a clockwise rotor system). Adjust the cyclic to
obtain cruising airspeed and a level flight atti tude as the
desired altitude is reached.
Common Errors
1. Failure to maintain constant angle of decent dur ing
training.
2. Failure to level-off the aircraft sufficiently, which
results in recovery below the desired altitude.
3. Failure to adjust antitorque pedal pressures for changes
in power.
Vertical Takeoff to a Hover
A vertical takeoff to a hover involves flying the helicopter
from the ground vertically to a skid height of two to three
feet, while maintaining a constant heading. Once the desired
skid height is achieved, the helicopter should remain nearly
motionless over a reference point at a constant altitude and
on a constant heading. The maneuver requires a high degree
of concentration and coordination.
Technique
The pilot on the controls needs to clear the area left, right,
and above to perform a vertical takeoff to a hover. The
pilot should remain focused outside the aircraft and obtain
clearance to take off from the controlling tower. If necessary,
the pilot who is not on the controls assists in clearing the
aircraft and provides adequate warning of any obstacles and
any unannounced or unusual drift/altitude changes.
Heading control, direction of turn, and rate of turn at hover
are all controlled by using the pedals. Hover height, rate of
ascent, and the rate of descent are controlled by using the
collective. Helicopter position and the direction of travel are
controlled by the cyclic.
After receiving the proper clearance and ensuring that the
area is clear of obstacles and traffic, begin the maneuver with
the collective in the down position and the cyclic in a neutral
position, or slightly into the wind. Very slowly increase the
collective until the helicopter becomes light on the skids or
wheels. As collective and torque increases, antitorque must
be adjusted as well. Therefore, as the aircraft begins to get
light on the landing gear, apply appropriate antitorque pedal
to maintain aircraft heading. Continue to apply pedals as
necessary to maintain heading and coordinate the cyclic for
a vertical ascent. As the helicopter slowly leaves the ground,
check for proper attitude control response and helicopter
center of gravity. A slow ascent will allow stopping if
responses are outside the normal parameters indicating hung
or entangled landing gear, center of gravity problems, or
control issues. If a roll or tilt begin, decrease the collective
and determine the cause of the roll or tilt. Upon reaching the
desired hover altitude, adjust the flight controls as necessary
to maintain position over the intended hover area. Student
pilots should be reminded that while at a hover, the helicopter
is rarely ever level. Helicopters usually hover left side low
due to the tail rotor thrust being counteracted by the main
rotor tilt. A nose low or high condition is generally caused
by loading. Once stabilized, check the engine instruments
and note the power required to hover.
Excessive movement of any flight control requires a change
in the other flight controls. For example, if the helicopter
drifts to one side while hovering, the pilot naturally moves
the cyclic in the opposite direction. When this is done,
part of the vertical thrust is diverted, resulting in a loss of
altitude. To maintain altitude, increase the collective. This
increases drag on the blades and tends to slow them down. To
counteract the drag and maintain rpm, increase the throttle.
Increased throttle means increased torque, so the pilot must
add more pedal pressure to maintain the heading. This can
easily lead to overcontrolling the helicopter. However, as
level of proficiency increases, prob lems associated with
overcontrolling decrease. Helicopter controls are usually
more driven by pressure than by gross control movements.
Common Errors
1. Failing to ascend vertically as the helicopter becomes
airborne.
2. Pulling excessive collective to become airborne,
causing the helicopter to gain too much altitude.
3. Overcontrolling the antitorque pedals, which not only
changes the heading of the helicopter, but also changes
the rpm.