Maintenance records are the backbone of aviation safety accountability. Every time an airframe, engine, propeller, appliance, or avionics system is inspected, repaired, overhauled, or altered, the work must be documented — and that documentation must be kept for a legally specified period and made available to authorized parties on demand. For Aviation Maintenance Technicians (AMTs), understanding these requirements is not merely a matter of passing the General knowledge exam; it is a day-to-day professional obligation backed by federal regulation.
The rules governing the retention and availability of maintenance records are found primarily in 14 CFR Part 91 (for general aviation operators), with additional provisions in Parts 121, 125, and 135 for commercial operations. The foundational definitions and baseline standards, however, are in Part 91, and that is where the FAA knowledge test draws its questions. This article focuses on the Part 91 framework, with notes on how related regulations interact.
What Records Must Be Kept
Under 14 CFR §91.417, the registered owner or operator of a civil aircraft is responsible for maintaining records related to the aircraft's airworthiness. These records fall into two broad categories based on how long they must be retained.
The first category consists of records that must be kept for the life of the aircraft — or more precisely, until the work they describe is superseded by equivalent work or until the aircraft is destroyed, exported, or retired from service. These permanent-type records include:
- The total time in service of the airframe, each engine, each propeller, and each rotor (for rotorcraft).
- The current status of each life-limited part of each airframe, engine, propeller, rotor, and appliance.
- The time since the last overhaul of all items installed on the aircraft that are required to be overhauled on a specified time basis.
- The current inspection status of the aircraft, including the time since the last required inspection by each type of inspection program used.
- The current status of applicable Airworthiness Directives (ADs), including the method of compliance, the AD number, revision date, and — if the AD involves recurring action — the time and date when the next action is required.
- Copies of any FAA Form 337s (Major Repair and Alteration forms) for major repairs or alterations performed on airframe, powerplant, propeller, or appliance.
The second category covers records that must be retained for a minimum period but do not need to be kept indefinitely. Specifically, records of maintenance, preventive maintenance, and alterations — other than the permanent-type entries above — must be kept for at least one year from the date the work was performed, or until the work is repeated or superseded by other work, whichever is later. These are sometimes called the "rolling" records because routine inspection entries and minor repair records cycle through this one-year window.
How the Records Are Organized in Practice
In general aviation, these records are typically maintained in aircraft logbooks — separate logbooks for the airframe, the engine(s), and the propeller(s). Some owners also maintain an avionics or equipment log. The logbooks serve as the running record for routine maintenance entries, while the FAA Form 337 and AD compliance sheets often travel with the aircraft as separate documents.
It is important to note that the regulation assigns responsibility for record-keeping to the registered owner or operator, not directly to the AMT who performed the work. However, the technician's signature and certificate number create a legal record of accountability, and the AMT bears responsibility for the accuracy and completeness of any entry they make. An entry that is incomplete, unsigned, or missing required information — such as the date, description of work, aircraft registration, and the technician's certificate type and number — is a regulatory deficiency.
Availability Requirements: Inspection on Demand
Keeping records is only half the obligation. Under 14 CFR §91.417(c), the owner or operator must make these maintenance records available for inspection by the FAA, the National Transportation Safety Board (NTSB), or any other authorized person upon request. In practice, this means the records must be readily accessible — not buried in a storage unit across the country or locked away without a means to retrieve them quickly.
When an aircraft changes hands, the seller is required to transfer the maintenance records to the new owner. This transfer is a legal obligation, not merely a courtesy. A buyer who cannot obtain the full maintenance history of an aircraft should treat this as a serious red flag, since missing records — especially missing FAA Form 337s for major repairs or missing AD compliance documentation — can ground the aircraft until the deficiency is resolved or the work is re-accomplished and re-documented.
FAA Form 337: A Closer Look
The FAA Form 337 deserves special attention because it is central to the permanent record requirement. Whenever a major repair or major alteration is performed on a U.S.-registered civil aircraft, a Form 337 must be completed in duplicate. One copy goes to the FAA Aircraft Registration Branch in Oklahoma City (or, for major repairs/alterations to powerplants and propellers, to the local Flight Standards District Office per the instructions on the form). The second copy is retained with the aircraft's maintenance records. This copy travels with the aircraft permanently — it is a record of a structural or systems change that affects airworthiness and must be available to any future inspector or owner.
The AMT or Designated Airworthiness Representative (DAR) who approves the work signs Block 7 (or Block 8 for field approvals). An unsigned or improperly completed Form 337 does not constitute a legal approval to return the aircraft to service.
Key Numbers and Rules
- Permanent records (life-limited parts, AD status, overhaul times, Form 337s): Retained for the life of the aircraft or until the specific information is superseded.
- Routine maintenance records (inspection entries, minor repairs): Retained for a minimum of one year from the date of the work, or until superseded, whichever is later.
- Governing regulation: 14 CFR §91.417 — every AMT should read this section in full.
- Responsible party: The registered owner or operator — though the AMT creating the record is accountable for its accuracy.
- Form 337 copies: One copy retained with the aircraft records permanently; one copy submitted to FAA.
- Transfer on sale: Maintenance records must be transferred to the new owner when the aircraft is sold.
- Inspection on demand: Records must be made available to FAA, NTSB, or other authorized persons upon request — §91.417(c).
Why It Matters: Safety and Legal Consequences
The rationale behind these requirements is straightforward: an aircraft's maintenance history tells the story of its airworthiness. A technician performing an annual inspection needs to know the current AD compliance status, the time remaining on life-limited parts, and whether any major alterations have changed the aircraft from its type-certificated design. Without complete records, that inspection cannot be conducted properly.
From a legal standpoint, failure to maintain or produce required records can result in civil penalties against the owner or operator and potential certificate action against the AMT who made or failed to make a required entry. The FAA takes falsification of records extremely seriously — intentionally false entries in a maintenance record are a federal offense under 14 CFR §43.12 and can result in suspension or revocation of an AMT certificate, among other enforcement actions.
Beyond the regulatory consequences, poor record-keeping contributes to accidents. Untracked life-limited parts that exceed their service life, undocumented modifications that confuse future technicians, and missing AD compliance records have all played roles in aviation incidents. Complete, accurate, readily available records are a frontline safety tool.
Common Test Traps
- Confusing the two retention periods: The FAA test frequently offers answer choices that swap the periods. Remember — permanent records (life-limited parts, ADs, overhaul times, Form 337s) are kept indefinitely; routine maintenance records are kept for a minimum of one year.
- Assigning responsibility to the wrong party: Many students think the AMT is responsible for retaining the records. The regulation places retention responsibility on the owner or operator. The AMT is responsible for making accurate entries.
- Forgetting that the transfer of records is mandatory: On a sale, records must transfer. This is not optional and is tested directly.
- Misidentifying what requires a Form 337: Only major repairs and major alterations require a Form 337. Minor repairs and minor alterations are documented in the maintenance record logbook only — no Form 337 is required.
- Assuming records only need to be available to the FAA: §91.417(c) extends availability to the NTSB and any other authorized person — not just FAA inspectors. This distinction occasionally appears in test questions.
Mastering the retention and availability rules under 14 CFR §91.417 will serve you throughout your career. Whether you are signing off a routine 100-hour inspection or completing a complex major alteration, the paper trail you create and the records you preserve are as much a part of the job as the wrench in your hand.