Aircraft Maintenance

Parts manufacturer approval falls under the Code of Federal Regulations Title 14 (14 CFR) Part 21 Subpart K, ' 21.303 FAA Order 8110-42A. Order 8110-42A is a 74-page document that offers detailed explanations, sample letters, and checklists to help work through the process. It also has a flow chart outlining the steps of applying and obtaining a PMA. (Please refer to graphic on page 35).

PMAs came about initially after World War II in response to aircraft manufacturers who did not want to keep making parts for older aircraft. The focus at that time was on designing and developing new aircraft and the older aircraft market was left behind.

A PMA is issued for the production of modification or replacement parts, which includes materials, parts, processes, and appliances.

PMAs differ from a supplemental type certificate (STC) as an STC is a type certificate issued when an applicant has received FAA approval to modify an aircraft from its original design. The supplemental type certificate, which incorporates by reference the related type certificate, approves not only the modification, but how that modification affects the original design.
When a PMA is issued to an applicant, the PMA is both a design and production approval. The PMA holder must adhere to design and production obligations in order to maintain the approval.

The path to PMA
Robert Reiff, president of Reiff Preheat Systems in Fort Atkinson, Wisconsin, tells his story on how his company achieved the PMA for its engine preheat system.