Certificate requirements

This regulation establishes who must hold FAA airman certificates when performing maintenance work on Part 121 aircraft (commercial airlines).

Anyone directly in charge of maintenance, preventive maintenance, alterations, or required inspections must hold an appropriate airman certificate—typically an A&P (Airframe and Powerplant) mechanic certificate or inspection authorization. The same applies to anyone actually performing required inspections.

A person "directly in charge" means someone responsible for overseeing a maintenance shop or station's work that affects aircraft airworthiness. This supervisor doesn't need to constantly watch every worker, but must be available for consultation and decisions when workers need guidance beyond their authority level.

The one exception: if a certificated repair station located outside the United States performs the work, these certificate requirements don't apply. This allows airlines to use qualified foreign repair facilities without requiring those facilities' personnel to hold FAA certificates.

*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.*