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 tachometer, flaps, or stall warning device,
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 aircraft 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 an aircraft,
particularly if other items are inoperative. Further information
regarding MELs and operations with inoperative equipment
can be found in AC 91-67, Minimum Equipment Requirements
for General Aviation Operations Under FAR Part 91.
Preventive Maintenance
Preventive maintenance is regarded as simple or minor
preservation operations and the replacement of small standard
parts, not involving complex assembly operations. Allowed
items of preventative maintenance are listed and limited to
the items of 14 CFR part 43, appendix A(c).
Maintenance Entries
All pilots who perform preventive maintenance must make
an entry in the maintenance record of the aircraft. The entry
must include the following information:
1. A description of the work, such as “changed oil (Shell
Aero-50) at 2,345 hours”
2. The date of completion of the work performed
3. The pilot’s name, signature, certificate number, and
type of certificate held
Examples of Preventive Maintenance
The following examples of preventive maintenance are taken
from 14 CFR, part 43, Maintenance, Preventive Maintenance,
Rebuilding, and Alternation, which should be consulted for a
more in-depth look at the preventive maintenance a pilot can
perform on an aircraft. Remember, preventive maintenance
maintenance (removal always will), it must be accomplished
by certificated maintenance personnel and recorded in
accordance with 14 CFR part 43.
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, part 91,
section 91.213(d).
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.
All small rotorcraft, non-turbine powered airplanes, gliders,
or lighter-than-air aircraft operated under 14 CFR part 91
are eligible to use the maintenance deferral provisions of 14
CFR, part 91, section 91.213(d). However, once 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 aircraft. All maintenance deferrals must
be accomplished in accordance with the terms and conditions
of the MEL and the operator-generated procedures document.
The use of an MEL for an aircraft operated under 14
CFR 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 aircraft.
The FAA has developed master minimum equipment lists
(MMELs) for aircraft in current use. Upon written request by
an operator, the local 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 aircraft during each operation.
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 would then either be
repaired or deferred in accordance with the MEL. Upon
is limited to work that does not involve complex assembly
operations including the following:
• Removal, installation, and repair of landing gear
tires and shock cords; servicing landing gear shock
struts by adding oil, air, or both; servicing gear wheel
bearings; replacing defective safety wiring or cotter
keys; lubrication not requiring disassembly other than
removal of nonstructural items, such as cover plates,
cowlings, and fairings; making simple fabric patches
not requiring rib stitching or the removal of structural
parts or control surfaces. In the case of balloons,
the making of small fabric repairs to envelopes
(as defined in, and in accordance with, the balloon
manufacturer’s instructions) not requiring load tape
repair or replacement.
• Replenishing hydraulic fluid in the hydraulic
reservoir; refinishing decorative coating of fuselage,
balloon baskets, wings, tail group surfaces (excluding
balanced control surfaces), fairings, cowlings,
landing gear, cabin, or flight deck interior when
removal or disassembly of any primary structure
or operating system is not required; applying
preservative or protective material to components
where no disassembly of any primary structure or
operating system is involved and where such coating
is not prohibited or is not contrary to good practices;
repairing upholstery and decorative furnishings of the
cabin, flight deck, or balloon basket interior when the
repair does not require disassembly of any primary
structure or operating system or interfere with an
operating system or affect the primary structure of
the aircraft; making small, simple repairs to fairings,
nonstructural cover plates, cowlings, and small
patches and reinforcements not changing the contour
to interfere with proper air flow; replacing side
windows where that work does not interfere with the
structure or any operating system, such as controls,
electrical equipment, etc.
• Replacing safety belts, seats or seat parts with
replacement parts approved for the aircraft, not
involving disassembly of any primary structure or
operating system, bulbs, reflectors, and lenses of
position and landing lights.
• Replacing wheels and skis where no weight-and-
balance computation is involved; replacing any
cowling not requiring removal of the propeller or
disconnection of flight controls; replacing or cleaning
spark plugs and setting of spark plug gap clearance;
replacing any hose connection, except hydraulic
connections; however, prefabricated fuel lines may
be replaced.
• Cleaning or replacing fuel and oil strainers or filter
elements; servicing batteries, cleaning balloon burner
pilot and main nozzles in accordance with the balloon
manufacturer’s instructions.
• The interchange of balloon baskets and burners on
envelopes when the basket or burner is designated as
interchangeable in the balloon type certificate data
and the baskets and burners are specifically designed
for quick removal and installation; adjustment
of nonstructural standard fasteners incidental to
operations.
• The installations of anti-misfueling devices to reduce
the diameter of fuel tank filler openings only if the
specific device has been made a part of the aircraft type
certificate data by the aircraft manufacturer, the aircraft
manufacturer has provided FAA-approved instructions
for installation of the specific device, and installation
does not involve the disassembly of the existing tank
filler opening; troubleshooting and repairing broken
circuits in landing light wiring circuits.
• Removing and replacing self-contained, front
instrument panel-mounted navigation and
communication devices that employ tray-mounted
connectors which connect the unit when the unit
is installed into the instrument panel (excluding
automatic flight control systems, transponders, and
microwave frequency distance measuring equipment
(DME)). The approved unit must be designed to be
readily and repeatedly removed and replaced, and
pertinent instructions must be provided. Prior to the
unit’s intended use, an operational check must be
performed in accordance with the applicable sections
of 14 CFR part 91 on checking, removing, and
replacing magnetic chip detectors.
• Inspection and maintenance tasks prescribed and
specifically identified as preventive maintenance in
a primary category aircraft type certificate or STC
holder’s approved special inspection and preventive
maintenance program when accomplished on a
primary category aircraft.
• Updating self-contained, front instrument panel-
mounted air traffic control (ATC) navigational
software databases (excluding those of automatic
flight control systems, transponders, and microwave
frequency DME), only if no disassembly of the unit is
required and pertinent instructions are provided; prior
to the unit’s intended use, an operational check must
be performed in accordance with applicable sections
of 14 CFR part 91.
Certificated pilots, excluding student pilots, sport pilots, and
recreational pilots, may perform preventive maintenance on
any aircraft that is owned or operated by them provided that
the aircraft is not used in air carrier service and does not
qualify under 14 CFR parts 121, 129, or 135. A pilot holding
a sport pilot certificate may perform preventive maintenance
on an aircraft owned or operated by that pilot if that aircraft is
issued a special airworthiness certificate in the LSA category.
(Sport pilots operating LSA should refer to 14 CFR part 65
for maintenance privileges.) 14 CFR part 43, appendix A,
contains a list of the operations that are considered to be
preventive maintenance.
Repairs and Alterations
Repairs and alterations are classified as either major or minor.
14 CFR part 43, appendix A, describes the alterations and
repairs considered major. Major repairs or alterations shall
be approved for return to service on FAA Form 337, Major
Repair and Alteration, by an appropriately rated certificated
repair station, an FAA-certificated A&P mechanic holding an
IA, or a representative of the Administrator. Minor repairs and
minor alterations may be approved for return to service with a
proper entry in the maintenance records by an FAA-certificated
A&P mechanic or an appropriately certificated repair station.
For modifications of experimental aircraft, refer to the
operating limitations issued to that aircraft. Modifications
in accordance with FAA Order 8130.2, Airworthiness
Certification of Aircraft and Related Products, may require
the notification of the issuing authority.
Special Flight Permits
A special flight permit is a Special Airworthiness Certificate
authorizing operation of an aircraft that does not currently
meet applicable airworthiness requirements but is safe
for a specific flight. Before the permit is issued, an FAA
inspector may personally inspect the aircraft or require it to
be inspected by an FAA-certificated A&P mechanic or an
appropriately certificated repair station to determine its safety
for the intended flight. The inspection shall be recorded in
the aircraft records.
The special flight permit is issued to allow the aircraft to be
flown to a base where repairs, alterations, or maintenance
can be performed; for delivering or exporting the aircraft; or
for evacuating an aircraft from an area of impending danger.
A special flight permit may be issued to allow the operation
of an overweight aircraft for flight beyond its normal range
over water or land areas where adequate landing facilities
or fuel is not available.
If a special flight permit is needed, assistance and the
necessary forms may be obtained from the local FSDO
or Designated Airworthiness Representative (DAR).
[Figure 9-10]
Airworthiness Directives (ADs)
A primary safety function of the FAA is to require correction
of unsafe conditions found in an aircraft, aircraft engine,
propeller, or appliance when such conditions exist and are
likely to exist or develop in other products of the same design.
The unsafe condition may exist because of a design defect,
maintenance, or other causes. Airworthiness Directives
(ADs), under 14 CFR, part 39, define the authority and
responsibility of the Administrator for requiring the necessary
corrective action. ADs are used to notify aircraft owners and
other interested persons of unsafe conditions and to specify
the conditions under which the product may continue to be
operated. ADs are divided into two categories:
1. Those of an emergency nature requiring immediate
compliance prior to further flight
2. Those of a less urgent nature requiring compliance
within a specified period of time
ADs are regulatory and shall be complied with unless a
specific exemption is granted. It is the responsibility of the
aircraft owner or operator to ensure compliance with all
pertinent ADs, including those ADs that require recurrent
or continuing action. For example, an AD may require a
repetitive inspection each 50 hours of operation, meaning
the particular inspection shall be accomplished and recorded
every 50 hours of time in service. Owners/operators are
reminded that there is no provision to overfly the maximum
hour requirement of an AD unless it is specifically written
into the AD. To help determine if an AD applies to an
amateur-built aircraft, contact the local FSDO.
14 CFR, part 91, section 91.417 requires a record to be
maintained that shows the current status of applicable
ADs, including the method of compliance; the AD number
and revision date, if recurring; next due date and time; the
signature; type of certificate; and certificate number of the
repair station or mechanic who performed the work. For ready
reference, many aircraft owners have a chronological listing
of the pertinent ADs in the back of their aircraft, engine, and
propeller maintenance records.
All ADs and the AD Biweekly are free on the Internet
at http://rgl.faa.gov and are available through e-mail.
Individuals can enroll for the e-mail service at the website
above. Paper copies of the Summary of Airworthiness
Directives and the AD Biweekly may be purchased from
the Superintendent of Documents. The Summary contains
all the valid ADs previously published and is divided into