The question
A logbook entry shows a bracket, a fitting, or a fuel-system part replaced — and there is no PMA marking on it and no FAA Form 8130-3 behind it. Is that an illegal part, or a legal one the regulations specifically allow? Both exist, and in the records the difference between them is documentation, not appearance.
What the rule actually allows
14 CFR 21.9 governs replacement and modification parts, and it is broader than "PMA or nothing." A part is acceptable if it is produced under a type certificate or an FAA production approval such as PMA or TSO; if it is a standard part "manufactured in compliance with a government or established industry specification" — the AN, MS, and NAS hardware most owners never think twice about; if it is a commercial part as defined in the rule; or if it is "produced by an owner or operator for maintaining or altering that owner or operator's product." That last clause is the owner-produced-part exception, and it is real — but narrow. FAA guidance has long read it to require the owner's actual participation in producing the part, not merely buying one from a third party and calling it owner-produced.
Producing a part is not installing it
The 21.9 exception addresses who may produce a part, not who may install it or approve it for return to service. Installation and return to service still require a person authorized under 14 CFR 43.3, the part must still conform to the approved design data for the aircraft, and if the work rises to a major repair or alteration it still requires an FAA Form 337. An owner-produced part installed and documented correctly is legal; the same part with no data basis and no authorized return-to-service entry is a discrepancy wearing the same clothes.
Where the records show the gap
On a pre-purchase records review, parts traceability is one of the most revealing lines. A part carrying no PMA or TSO marking, no 8130-3 or manufacturer certification, and no owner-produced-part documentation is a traceability gap — and the gap matters more the closer the part sits to primary structure, the engine, or the fuel system. A single unmarked bracket is a question; an undocumented fuel fitting or a structural part with no approval basis is a finding that changes the risk picture.
What cannot be concluded
A records review flags parts that lack a traceable approval basis; it does not determine that a part is unapproved, nonconforming, or unairworthy, and it does not approve anything for return to service. Whether an installed part conforms to the approved design and may remain on the aircraft is for the responsible IA to determine against current data.
What to request or verify next
- The 8130-3, PMA or TSO evidence, or manufacturer certification for major and safety-critical installed parts.
- For any owner-produced part, documentation of the owner's participation in its production and the design data it was built to.
- A Form 337 for any part installed as part of a major repair or alteration.
- Independent IA review of any engine, structural, or fuel-system part whose approval basis is not documented, before funds move.