Aircraft part
Approved components for type-certificated aircraft, regulated by aviation authorities.
An aircraft part is any component approved to be installed on a type-certificated aircraft. The approval process depends on the regulations of the country where the aircraft is registered. In the United States, the Federal Aviation Administration manages this approval under Federal Aviation Regulation Part 21.
Parts can be made under a Production Certificate, which allows the holder to produce parts from the approved type design; these are considered approved parts. Another method is a Parts Manufacturer Approval (PMA), which authorizes the production of replacement or modification parts for a type-certificated product, also making them approved parts. Parts and assemblies made under a Technical Standard Order Authorization (TSOA) are likewise approved.
The FAA also allows aircraft owners or operators to produce their own replacement parts from scratch, using the original as a template with the same dimensions and materials. This is documented in the logbooks as an "owner-produced part" under FAR §21.9(a)(5). The owner can enlist help from an A&P mechanic, a machine shop, or any certified or uncertified personnel, and the part still qualifies as owner-produced. This right is granted only for installation on the owner’s own aircraft, not for sale or installation on another owner’s aircraft (which would require PMA approval). The part must still be airworthy and conform to the aircraft’s type design. An A&P who agrees the part is airworthy and considers the installation a minor repair can approve the aircraft for return to service. The FAA considers a part owner-produced if the owner is meaningfully involved by providing specifications or the part to duplicate, providing materials, providing manufacturing techniques or assembly methods, providing quality assurance, or supervising the part’s manufacture.
Life-limited parts are those that, as a condition of their type certificate, cannot exceed a specified time or number of operating cycles in service, as defined by Canadian Aviation Regulations (CAR 101.01). Flight-critical parts, such as navigation systems, communication systems, and traffic collision avoidance systems (TCAS), are typically regulated by the FAA and the European Union.
Some high-value aircraft parts can be repaired through re-manufacturing processes like machining, welding, or plating.
- Market value 2016
- $4.5 billion
- Market value 2026
- $7.7 billion
- Aircraft retirements decade
- 9,300
- Narrowbody retirements decade
- 4,000
Lore & Background
Aircraft parts may be produced under several approval pathways. A Production Certificate holder may produce parts from the type design, and such parts are considered approved. Parts Manufacturer Approval (PMA) allows production of replacement or modification parts. Technical Standard Order Authorization (TSOA) also yields approved parts. Owners or operators may produce parts for their own aircraft under FAR §21.9(a)(5), provided they are meaningfully involved in specification, materials, techniques, quality assurance, or supervision; these owner-produced parts must conform to type design and be deemed airworthy by an A&P mechanic.
Life limited parts are those that, as a condition of their type certificate, may not exceed a specified time or number of operating cycles. Flight critical parts, such as navigation and communication systems and TCAS, are regulated by the FAA and the European Union. Some high-value parts can be repaired using processes like machining, welding, or plating, guided by Advisory Circular 43.13-1B.
Suspected unapproved parts are those deemed unairworthy due to design, manufacture, or distribution conflicts with regulations. Indicators include missing or counterfeit certification, manipulated identification plates, physical deviations, poor workmanship, or suspiciously low price. Such parts must be reported to the national aviation authority. Trade associations representing the industry include the Aerospace Industries Association, General Aviation Manufacturers Association, Modification and Replacement Parts Association, Aeronautical Repair Station Association, and Aviation Suppliers Association.
Reader's Guide
The concept of an aircraft part is central to aviation safety and regulatory compliance. The article establishes that approval derives from national jurisdictions, with the FAA governing U.S. parts under Part 21. Multiple approval methods—Production Certificate, PMA, TSOA, and owner-produced parts—provide flexibility while maintaining airworthiness standards. The distinction between approved and unapproved parts is critical, as suspected unapproved parts must be reported and are ineligible for installation. The article notes economic trends: low jet fuel prices and program delays have extended airliner service lives, increasing reliance on used parts, with the market projected to grow from $4.5 billion in 2016 to $7.7 billion in 2026. Life limited parts from CFM56 engines are particularly prized. The industry is represented by several trade associations covering manufacturers, repair stations, and distributors. The article does not resolve any disputes but presents the regulatory framework and market dynamics as described.
Did You Know?
- Owner-produced parts may be made with the aid of an A&P, machine shop, or any certified or uncertified personnel, as long as the owner is meaningfully involved.
- Life limited parts from CFM56 engines are among the most prized used parts.
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