Chapter 12. Publications, Forms, & Records
Subpart E — Maintenance, Preventive Maintenance, and Alterations
§91.401 — Applicability
Although this subpart describes in general the rules regarding maintenance, preventive maintenance, and alteration, certain sections do not apply if the aircraft is operated in accordance with part 121, 125, 129, or 135.
§91.403 — General
The owner/operator holds the primary responsibility for maintaining the aircraft in airworthy condition. This includes compliance with all applicable airworthiness directives and is the reason that the FAA sends new AD notes to the registered owners of the affected aircraft. All maintenance performed must be accomplished in accordance with part 43. Compliance with the appropriate manufacturer maintenance manuals and Instructions for Continued Airworthiness is also required. Mandatory replacement times, inspection intervals, and related procedures as specified in the FAA-approved operations specifications must also be complied with.
§91.405 — Maintenance required
The owner/operator is required to have the appropriate inspections made, and to have discrepancies repaired in accordance with part 43. He or she is also required to ensure that the appropriate entries have been made in the maintenance records. Any inoperative instruments or equipment must be properly placarded as inoperative.
§91.407 — Operation after maintenance, preventive maintenance, rebuilding or alteration
Whenever the aircraft has undergone maintenance, preventive maintenance, rebuilding or alteration, it must have been approved for return to service and a proper entry made in the maintenance records. If the maintenance that was done could have appreciably changed the flight characteristics, an appropriately rated pilot must perform an operational flight check of the aircraft and must make an entry of the flight in the maintenance records. If ground testing and inspection can show conclusively that the maintenance has not adversely affected the flight characteristics, no flight test is required.
§91.409 — Inspections
This section identifies various types of inspection applicable to the civilian aircraft fleet. Paragraph (a) defines the requirement for an annual inspection. However, there are certain exceptions to this regulation:
Annual inspections are usually the inspection method associated with small “general aviation" aircraft. If this same aircraft is used for hire (including flight instruction for hire), then the aircraft must also be inspected every 100 hours of time in service. This requirement for a 100-hour inspection to be conducted on an aircraft may be exceeded by as much as 10 hours if the aircraft is en route to reach a facility that will be conducting the inspection. Any time accrued between 100 and 110 hours is subtracted from the hours remaining before the next 100-hour inspection.
Since aircraft used for hire only generate revenue when they are flying, any time that the aircraft is “down for inspection" can result in a loss of income for the owner/operator. Therefore, the FAA has made provision to minimize the impact of the 100-hour and annual inspection requirement. The owner/operator may petition the local FSDO for approval of a progressive inspection program. This program breaks the complete inspection of the aircraft into smaller, less time-consuming steps. (Refer to part 43, appendix D.) This inspection may be either performed or supervised by a technician holding an Inspection Authorization (IA). The program must ensure at all times that the aircraft is airworthy. The owner/operator must submit an inspection schedule with his or her application to the FAA. This schedule must identify the time intervals (hours or days) when routine and detailed inspections are to be accomplished. (Refer to §43.15.) Just as with the 100-hour inspection, a 10-hour maximum extension of a specified inspection interval is allowed if the aircraft is en route. A change in the inspection interval is also allowed for changes in service experience.
If the progressive inspection is discontinued, the aircraft will again be subject to the traditional annual and 100-hour inspections.
Other inspection programs, which may be applicable to other aircraft, are a continuous airworthiness inspection program and an approved aircraft inspection program (AAIP). The former program is applicable to either a part 121 or 135 carrier, but the latter program is limited to part 135 operators only. Finally, the owner/operator may use either a current inspection program recommended by the aircraft manufacturer or one established by the owner/operator and approved by the local FSDO. Any subsequent changes to that program must also be approved by the local FSDO.
There may be an instance when the operator of an aircraft wishes to change from one type of inspection program to another. In that case the time in service, calendar times, or cycles of operation from the current program must be carried over to the subsequent program.
§91.410 — Special maintenance program requirements
After the separation of an 18-foot section of the upper fuselage area of an Aloha Airlines Boeing 737 in 1988, Boeing, the FAA, and the NTSB carefully studied this catastrophic failure. It was determined that corrosion and fatigue failure had occurred due to the numerous pressurization cycles this aircraft had experienced during its use by Aloha Airlines. This 19-year-old aircraft had over 90,000 landing cycles on it. The subsequent lessons learned from this event have led the FAA to impose flight cycle life limits on various commercial aircraft. Those limits and the specific aircraft impacted are identified in paragraph (a) of this section. Paragraph (b) specifies requirements for inspection of the fuel tank system on all turbine powered transport category aircraft having a passenger capacity of 30 or more, or a maximum certificated payload capacity of 7,500 pounds or more, if they were type certificated after January 1, 1958. This requirement is a result of the in-flight breakup of a 25-year-old Boeing Model 747- 100 series airplane on July 17, 1996, after takeoff from Kennedy International Airport in New York, resulting in 230 fatalities. The accident investigation conducted by the National Transportation Safety Board (NTSB) indicated that the center wing fuel tank exploded due to an unknown ignition source. This accident prompted the FAA to examine the underlying safety issues surrounding fuel tank explosions, the adequacy of the existing regulations, the service history of airplanes certificated to these regulations, and existing maintenance practices relative to the fuel tank system. This rule requires design approval holders of certain turbine-powered transport category airplanes, and of any subsequent modifications to these airplanes, to substantiate that the design of the fuel tank system precludes the existence of ignition sources within the airplane fuel tanks. It also requires developing and implementing maintenance and inspection instructions to assure the safety of the fuel tank system. For new type designs, this rule also requires demonstrating that ignition sources cannot be present in fuel tanks when failure conditions are considered, identifying any safety-critical maintenance actions, and incorporating a means either to minimize development of flammable vapors in fuel tanks or to prevent catastrophic damage if ignition does occur. These actions are based on accident investigations and adverse service experience, which have shown that unforeseen failure modes and lack of specific maintenance procedures on certain airplane fuel tank systems may result in degradation of design safety features intended to preclude ignition of vapors within the fuel tank.
§91.411 — Altimeter system and altitude reporting equipment tests and inspections
Commonly referred to as “the 411 test." This section specifies the requirements for testing the static pressure system, each altimeter instrument, and each automatic pressure altitude reporting system every 24 calendar months. The static system must also be tested any time it has been “opened and closed" except for the normal use of the system drain, and alternate static system pressure valves. If the automatic pressure altitude reporting system of the air traffic control (ATC) transponder is either installed or subjected to maintenance actions, the system must also be tested per appendix E of part 43.
Due to the inherent design and accuracy of this system, only certain persons may perform these tests: the aircraft manufacturer, a properly rated repair station, or a certificated airframe mechanic. It should be noted that the airframe technician may only perform the inspection and test of the static pressure system. Calibration and maintenance of related instruments is specifically prohibited to the technician by the language of 14 CFR§65.81 and specifically allowed in 14 CFR §145.59 for repair stations holding an “instrument rating."
TSO’d items are considered to be “tested and inspected" as of the date they were manufactured. The maximum altitude for which the system was tested is the maximum altitude at which the aircraft can be flown IFR in controlled airspace.
§91.413 — ATC transponder tests and inspections
This “413 test" is the other test required every 24 months. Whenever the ATC transponder is installed or has undergone maintenance, the complete system must be tested and inspected in accordance with appendix E of part 43. The transponder itself must be tested and inspected in accordance with appendix F of part 43. As with the 411 test, only certain persons are authorized to conduct the tests. They are: the manufacturer of the aircraft, a properly certificated repair station, or the holder of a continuous airworthiness maintenance program under part 121 or 135.
§91.415 — Changes to aircraft inspection programs
If the FAA determines that the inspection program established and approved under either §91.409 or 91.1109 must be revised to ensure continued safety and adequacy of the program, the owner/operator must make the necessary changes as identified by the Administrator. If the owner/operator desires to contest this request, they must petition the FAA to reconsider their request to change the program within 30 days of receiving the change request from the FAA.
§91.417 — Maintenance records
The understanding and implementation of this section is fundamental to the aircraft industry, in general, and the aircraft owner/operator, in specific. A professional maintenance technician should not only be knowledgeable of this section, but should also be able to help the owner/operator understand it. [Figure 12-9] This section identifies four types of records — two are quite specific (paragraphs (a) and (d)) and two are more general: (a)(1) and (a)(2). Paragraph (a) refers to the 411 and 413 testing, which requires testing every 24 months; therefore records must be kept for that length of time.
Paragraph (d) refers to the installation of fuel tanks in the cabin or cargo area. The FAA Form 337 authorizing this installation must be kept on board the aircraft all the time.
Note: Other than this paragraph, there is no requirement that the maintenance records of the aircraft be carried on the aircraft. In fact, there are very logical reasons that in most cases they shouldn’t be. The two biggest concerns are damaged or lost records. It is much safer to retain the logs in a filing system in the office. It is also a very wise idea to have the logbook copied or scanned, and retained at a separate location should a catastrophic event (fire, flood, tornado, hurricane, and so forth) occur at the site the original records are retained.
Subparagraph (a)(1) then lists those records which are later defined in (b)(1) as being only retained for 1 year or until the work is repeated or superseded. Subparagraph (a)(2) specifies the records that are permanent records, and are identified in subparagraph (b)(2) as those which must be transferred with the aircraft. Refer to the chart for further clarification. [Figure 12-9]
Paragraph (c) requires that all of the maintenance records mandated by this section be made available upon request to the Administrator or any authorized representative of the National Transportation Safety Board. Furthermore, the owner/operator must provide the Form 337 required to be aboard the aircraft whenever additional fuel tanks are installed in either the passenger compartment or the baggage compartment (per paragraph (d)) to any law enforcement officer upon request.
§91.419 — Transfer of maintenance records
When an aircraft is sold, it is logical that the records are transferred with it. They may be either in plain language or coded. However, the purchaser may elect to permit the seller to retain the actual records, but if that occurs, the purchaser (now the current owner/operator) must still make available upon request, these records to either the FAA or the NTSB.
§91.421 — Rebuilt engine maintenance records
This section presents the term “zero time." Although not truly given as a definition, the wording of the regulation is very clear that an aircraft engine, when rebuilt by the engine manufacturer or an agency approved by the manufacturer, may be given a new maintenance record, showing no previous operating history. This new record must include a signed statement with the date it was rebuilt, any changes incorporated by compliance with AD notes, and compliance with any of the manufacturer’s service bulletins.
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