The five routes a replacement or modification part can take onto a type-certificated aircraft, plus the European design-organisation route. Rule references are to 14 CFR Part 21 and to Annex I (Part 21) of Regulation (EU) No 748/2012.
| Type certificate holder (US) | PMA holder (US) | Owner-produced part (US) | Repair-station fabrication (US) | EASA Design Organisation Approval (EU) | |
|---|---|---|---|---|---|
| Legal basis | 14 CFR 21.9(a)(1), production under a type certificate | 14 CFR 21.9(a)(2) and 21.303, Parts Manufacturer Approval | 14 CFR 21.9(a)(5), produced by an owner or operator | 14 CFR 21.9(a)(6), fabricated by a rated certificate holder | Part 21 Subpart J, points 21.A.231 to 21.A.265 |
| What is approved | The design and the production system together | The design of the part and the production system | Nothing is approved in advance; the part must conform to FAA-approved data | Nothing is approved in advance; a fabrication quality control system is accepted | The organisation itself, and its capability to design |
| Who may hold it | The type certificate holder | Any person or company the FAA approves | Only the owner or operator of the aircraft the part goes on | A rated repair station or mechanic, under Part 43 | Any natural or legal person established in Europe |
| May the part be sold on its own | Yes | Yes | No — 21.9(b) forbids representing it as suitable | No — it must be consumed in the repair | Not applicable; the DOA approves designs, not parts production |
| Is the approval transferable | Yes, a type certificate may be transferred | No — 14 CFR 21.314 is one sentence with no exceptions | Not applicable, there is no approval to transfer | Not applicable, there is no approval to transfer | No — 21.A.249, except on a significant change of ownership |
| The paperwork that matters | Type certificate data sheet; part marked per 14 CFR 45 | FAA-PMA marking per 14 CFR 45.15(a) | A maintenance record under 14 CFR 43.9; FAA Form 337 for a major repair or alteration | A maintenance record under 14 CFR 43.9, per AC 43-18 | The Design Organisation Handbook, 21.A.243 |
| The sentence that defines it | Design and build the aircraft, and you may build its parts | Show the FAA your design and your quality system, and you may sell parts for someone else’s aeroplane | “We would not construe the ordering of a part, standing alone, as participating in controlling the design, manufacture, or quality of a part.” | “Fabricated … and consumed in the repair or alteration of a product or article in accordance with part 43” | The Agency “shall accept without further verification” the holder’s compliance documents, 21.A.263(b) |
Sources: 14 CFR 21.9, 21.303, 21.314 and 45.15 (eCFR); FAA Advisory Circulars 20-62E and 43-18; FAA Office of the Chief Counsel memorandum of 5 August 1993 on the definition of an owner-produced part; Regulation (EU) No 748/2012, Annex I (Part 21), Subpart J. Compiled by Afterburner, October 2026.