Summary of Essential Aircraft Maintenance Records

## Introduction Aircraft maintenance records document the history of inspections, repairs, alterations, and compliance actions for an aircraft. Accurate records are essential for safety, regulatory compliance, and maintaining the aircraft's value. > **Definition:** "Time in Service" means the time from the moment an aircraft leaves the surface of the earth until it touches it at the next point of landing. ## Key Concepts and Where to Record Them ### 1. Time in Service - Use the definition above whenever recording aircraft total time in service. - Practical example: If a flight departs at 09:00 and lands at 11:15, the time in service for that flight is 2 hours 15 minutes. ### 2. 100-Hour Inspection — Record Requirements When an aircraft is returned to service after a 100-hour inspection, the maintenance record entry must include: - Type of inspection (e.g., "100-hour inspection") - Extent of inspection (brief description of systems/components checked) - Date of the inspection - Aircraft total time in service at time of inspection - Signature of the person approving or disapproving return to service - Certificate number of that person - Rating of that person (e.g., A&P mechanic) > Example record entry: "100-hour inspection; oil change, control check, landing gear inspection; 2026-07-15; Total time in service: 2,450.2 hours; Approved by: J. Smith, A&P 123456789, Inspection Authorization." ### 3. Airworthiness Directives (ADs) — Record Requirements After complying with an AD, make an entry in the maintenance records that includes: - AD number and revision date - Date of compliance - Aircraft total time in service at compliance - Method of compliance (what action was taken) - Whether the AD is recurring; if recurring, time of next required compliance > Example entry: "AD 2021-05-10 R1; complied 2026-06-01; Total time: 3,120.7 hours; replaced actuator per AD instructions; Recurring: yes; next compliance at 3,620.7 hours." ### 4. Major Repair or Major Alteration — Where to Record - The description of a major repair or major alteration must be recorded on FAA Form 337. - FAA Form 337 becomes part of the aircraft maintenance records once completed. ### 5. Disposition of FAA Form 337 - After completion, provide one signed copy to the aircraft owner and one copy to the FAA. ### 6. Who Makes the 100-Hour Entry - The person performing the work (the mechanic or certificated individual) is responsible for making the entry in the aircraft records after a 100-hour inspection. ### 7. Retention Period for 100-Hour Inspection Records - The owner or operator must retain the record of a 100-hour inspection until the work is repeated or superseded by other work, or for one year after the 100-hour inspection was performed — whichever occurs first. ### 8. Transfer of AD Records on Sale - When an aircraft is sold, the aircraft records that contain the current list of Airworthiness Directives must be transferred to the purchaser at the time of sale. ## Tables — Quick Comparison | Item | What to Record | Where / How long | |---|---:|---| | Time in Service | Flight duration from takeoff to next landing | Use for total time when recording inspections/AD compliance | | 100-hour inspection entry | Type, extent, date, A/C total time, signature, cert number, rating | Retain until repeated/superseded or 1 year | | AD compliance entry | AD number/revision, date, A/C total time, method, recurring status, next time | Transfer with aircraft records on sale | | Major repair/alteration | Description on FAA Form 337 | Owner gets signed copy; FAA gets a copy | ## Practical Examples and Applications - Pre-buy inspection: Review FAA Form 337 entries to identify past major alterations. - Tracking recurring ADs: Use the AD compliance entry to set calendar or Hobbs/Tach reminders for the next compliance time. - Audit preparedness: Keep clear 100-hour entries with totals and certificated mechanic information to pass an FAA ramp check. Fun fact: Proper, comp