Aircraft parts

An aircraft part is an article or component approved for installation on a type-certificated aircraft. Approval for these parts is derived from the jurisdictions of the countries that an aircraft is based. In the United States, the Federal Aviation Administration oversees the approval for these parts under Federal Aviation Regulation Part 21.

A production certificate holder may produce parts from the type design that is associated with the production approval. Parts manufactured under a Production Certificate are considered to be "approved parts."

A Parts Manufacturer Approval, or PMA, is one way to obtain approval to produce replacement or modification parts for installation on a type-certificated product. Such parts are considered to be "approved parts."

Parts and assemblies may be produced under a Technical Standard Order Authorization (TSOA). Such parts are considered to be "approved parts."

The FAA permits the aircraft owner or operator to produce replacement parts from scratch (using the original as a template and using the same dimensions and materials), and document it in the logbooks as an "owner-produced part" in accordance with FAR §21.9(a)(5). In doing this, the owner could enlist the aid of an A&P, a machine shop, or anyone certified or uncertified personnel and the part would still qualify as an owner-produced part. This ability is granted by the FAA to aircraft owners/operators, so long as the parts they produce are for installation on their own aircraft and not for sale or for installation on an aircraft they do not own (which would require PMA approval instead). All owner-produced parts must still be considered airworthy, by conforming to the aircraft's type design. An A&P that agrees the owner-produced part is airworthy and that the installation is a considered a "minor repair" can approve the aircraft for return to service.

The FAA will consider a part to be owner-produced (and therefore legal) if the owner is meaningfully involved in its production in any of the following ways:

Life limited parts are parts that, as a condition of their type certificate, may not exceed a specified time, or number of operating cycles, in service [Canadian Aviation Regulations/ CAR 101.01]

Flight critical parts are usually regulated by the FAA and the European Union. These include, navigation systems, communication systems, traffic collision avoidance system (TCAS), etc.

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