Alteration and repair reports

When an airline (Part 121 certificate holder) completes a major alteration or major repair on an aircraft, engine, propeller, or appliance, it must promptly prepare a written report documenting the work.

For major alterations, the airline must submit a copy of the report to its assigned FAA inspector. For major repairs, the airline doesn't need to submit the report but must keep it available so the FAA inspector can review it during inspections.

This regulation ensures the FAA maintains oversight of significant maintenance work that could affect aircraft airworthiness. Major alterations typically change an aircraft's design or performance characteristics, so the FAA wants active notification. Major repairs restore the aircraft to its approved condition, so passive record-keeping suffices. The distinction helps the FAA track modifications to the fleet while allowing airlines to handle routine major repairs with less administrative burden.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*