Aircraft Logbooks

• The registered owner or operator must keep the maintenance records required by Title 14 of the Code of Federal Regulations (CFR) § 91.417 and ensure that maintenance personnel make the entries needed to show approval for return to service. The person who performs or approves work or an inspection makes the applicable entry under 14 CFR §§ 43.9 or 43.11.
• Maintenance records may be paper or electronic if the system preserves continuity, contains the required information, accepts signatures, permits new entries, and remains intelligible.
• A § 43.9 maintenance entry includes a description of the work or an acceptable-data reference, the completion date, the performer's name when different from the approving person, and the approving person's signature, certificate number, and kind of certificate.
• An inspection entry under § 43.11 identifies the inspection and its extent, the date and aircraft total time, the approving or disapproving person's credentials, and the required airworthy or discrepancy statement.
• For each applicable Airworthiness Directive, the continuing-status record shows the method of compliance, AD number and revision date, and, when the action recurs, the time and date the next action is required.
• Other continuing-status records include total time, life-limited-part status, time since required overhaul, current inspection status, and prescribed major-alteration forms. These records are retained and transferred with the aircraft at sale.
• Ordinary maintenance, alteration, and inspection records covered by § 91.417(a)(1) are retained until the work is repeated or superseded by other work, or for one year after the work is performed. A discrepancy list is retained until the defects are repaired and the aircraft is approved for return to service.
• An annual inspection completed during a month remains current through the last day of that same month 12 calendar months later. The 100-hour rule applies when carrying a person other than a crewmember for hire and when giving flight instruction for hire in an aircraft the instructor provides.
• Before flight, compare the last documented compliance date or time with the controlling interval and any next-due entry. A recent entry, current annual inspection, or normal exterior preflight does not clear an unresolved discrepancy or prove that every recurring requirement is current.
• Missing records do not automatically cancel the aircraft's registration, but they may prevent the owner, operator, or pilot from verifying inspections, life limits, AD compliance, and other continuing-airworthiness requirements. Required records may need to be reconstructed before lawful operation can be supported.
• Before purchasing a used aircraft, treat its maintenance status, records, and upcoming maintenance exposure as part of the acquisition decision rather than as matters to address after closing.
  • Have a reliable, independent maintenance professional examine both the aircraft and its complete records before negotiations have progressed too far, and require discrepancies to be corrected or addressed in the transaction documents.
  • Verify completed and upcoming inspections; total time and life-limited-part status; time since required overhauls; current and recurring Airworthiness Directive compliance; major alterations, damage, and repairs; and any maintenance-program enrollment or buy-in obligations.
  • Include the expected cost and downtime of major calendar- or usage-based inspections when evaluating the aircraft’s true acquisition cost; an aircraft with a lower purchase price may carry a substantial near-term maintenance obligation.
  • Define the pre-purchase inspection’s scope, acceptable aircraft condition, responsibility for discrepancies, required records, and the buyer’s right to withdraw before the deposit becomes nonrefundable.

Abbreviations used below: Federal Aviation Regulations (FAR).

• Aircraft owners/operators shall keep and maintain aircraft maintenance records per FAR 91.
  • The FAA does not specify in what form these logbooks must be maintained, provided the required information is present.
• Each person who maintains, performs preventive maintenance, rebuilds, or alters an aircraft, airframe, aircraft engine, propeller, appliance, or component part shall make an entry in the maintenance record of that equipment
• the person approving or disapproving for return to service an aircraft, airframe, aircraft engine, propeller, appliance, or component part after any inspection performed shall make an entry in the maintenance record of that equipment

• Each owner or operator to ensure that maintenance personnel make appropriate entries in the maintenance records to indicate that the aircraft has been approved for return to service.
  • Section 91.417(a) sets forth the content requirements and retention requirements for maintenance records.
  • Maintenance records may be kept in any format that provides record continuity, includes required contents, lends itself to the addition of new entries, provides for signature entry, and is intelligible.
  • Section 91.417(b) requires records of maintenance, alterations, and required or approved inspections to be. retained until the work is repeated, superseded by other work, or for one year
  • Section 91.417(b) requires records to be retained and transferred with the aircraft at the time of sale.
• Separate or individual records are not required for each engine, propeller, rotor, and appliance of an aircraft
• The information specified in 91.417(a)(1) through 91.417(a)(2)(vi) are required to be kept for each item as appropriate
• As a practical matter, many owners and operators find it advantageous to keep separate or individual records since it facilitates transfer of the record with the item when ownership changes
• Records are required to include "a description of the work performed".
  • The description should be in sufficient detail to permit a person unfamiliar with the work to understand what was done and the methods and procedures used.
  • To provide for extensive work, the rule permits reference to technical data acceptable to the Administrator in lieu of making the detailed entry.
  • Manufacturer's manuals, Service Letters (SL), bulletins, work orders, FAA ACs, and others, which accurately describe what was done or how it was done, may be referenced.
  • Except for the documents mentioned that are in common usage, referenced documents are to be made a part of the maintenance records and retained.
  • NOTE: Certificated Repair Stations (CRS) frequently work on components shipped to them without the maintenance records.
    • To provide for this situation, repair stations should supply owners and operators with copies of work orders written for the work, in lieu of maintenance record entries.
    • The work order copy must include the information required, be made a part of the maintenance record, and retained.
• Entries contain the date the work was completed, but in instances where one person conducted and another approved, there may be two dates.
  • In this instance, there should be two signatures, however, only one is required.

• Not all work may be logged, for example, that work done to correct a defect or mistake during manufacturing.
  • In this case, Non-Conforming Material Reports (NCMRs) or like reports, document the work at the factory.
  • These reports are not reflected in the aircraft logbooks as they occurred in the factory, and everything prior to the issuance of an airworthiness certificate are proprietary.
  • The result is potential differences from aircraft to aircraft and from maintenance manual to what is observed.
• When discrepancies are discovered during maintenance, the A&P must look into if the work is from a poor maintenance practice or a legitimate fix that is procedurally omitted from the logs

• Maintenance logs falsifications are a serious offense and may levy criminal charges.
• While many would not consider falsifying records themselves, beware that the owner/operator who rents or sells an aircraft may.