Glossary
Aircraft Mechanic Terms & Vocabulary
15 essential aircraft mechanic terms with plain-English definitions: the vocabulary you’ll hear in training and on day one.
Key aircraft mechanic vocabulary
These 15 terms come up constantly in aircraft mechanic training, on the job and in interviews. Knowing them helps you follow instructions, document accurately and sound prepared.
- 100-hour inspection
- An inspection required for certain aircraft used for hire.
- A&P
- Airframe and Powerplant: the FAA mechanic certificate ratings.
- Airworthiness
- An aircraft’s conformity to its approved design and condition for safe operation.
- Airworthiness directive (AD)
- A legally enforceable FAA rule requiring correction of an unsafe condition.
- Annual inspection
- A required yearly inspection for many general aviation aircraft, performed by an IA.
- Borescope
- A camera tool for inspecting inside engines.
- FOD
- Foreign object debris: loose items that can damage engines and aircraft.
- Logbook entry
- The required record of maintenance performed, including description, date and signature.
- MEL
- Minimum equipment list: items that may be inoperative while still flying under conditions.
- NDT
- Non-destructive testing, such as eddy current or dye penetrant inspection.
- Return to service
- Approval, documented in records, that an aircraft is airworthy after maintenance.
- RII
- Required inspection item: work that must be inspected by a second qualified person.
- Safety wire
- Wire used to prevent fasteners from loosening.
- Service bulletin
- A manufacturer’s recommendation for inspection or modification.
- Torque seal
- A paint marking showing a fastener was torqued.
Practice these terms
Test yourself with the free Aircraft Mechanic practice test: it includes vocabulary questions built from this list. For a complete course, see Aircraft Mechanic training.
Browse terms from every career in our career glossary.