FAA PMA vs OEM Parts

Given the numerous strict standards set by global authorities for what constitutes airworthiness, aviation buyers rightfully look at potential replacement parts with scrutiny. Outside of more general requirements, an aircraft’s continued airworthiness might be contingent upon the installation of approved parts either specified in the type design or those officially verified as functional equivalents. These two choices are respectively known as “OEM” and “PMA” parts. In this blog, we will lay out the differences between OEM and PMA aircraft parts and see if one holds a definitive advantage over the other for aircraft maintenance needs.

Defining Original Equipment Manufacturer (OEM)

OEM refers to the company that originally designed and produced the parts used during the assembly of an aircraft or engine and holds the Type Certificate (TC) or Supplemental Type Certificate (STC). As such, OEM aircraft parts are often viewed as the gold standard for compatibility, as they are supported by extensive technical documentation and frequently required for aircraft still under their warranty periods.

Understanding Parts Manufacturer Approval (PMA)

While OEMs dominate the initial production phase, the Federal Aviation Administration (FAA) allows for competition in the aftermarket through PMA, a combined design and production approval. To receive this, a manufacturer must undergo a multi-stage certification process for every component they intend to bring to market, involving:

• Design Approval: The applicant must first prove the part’s design is completely interchangeable with the OEM’s. This can be through a licensing agreement that grants them access to proprietary design data or Test and Computation, a process involving in-depth engineering analysis and physical testing to prove the part meets or exceeds the performance of the original.
• Production Quality System Certification: In accordance with Title 14 CFR Part 21, Subpart K, manufacturers are required to have a documented set of procedures for inspecting raw materials, carrying out manufacturing processes, and performing final testing to avoid any physical defects or quality deviations. This also extends to protocols for tracking and reporting any failures or malfunctions back to the FAA. 
• FAA Audit and Authorization: After everything else is validated, the FAA will perform a facility audit to verify that the manufacturer can consistently produce parts that meet the approved specifications. If the applicant passes this inspection, the FAA issues a PMA Letter of Authorization that lists the part number and certain aircraft or engine models for which it is fit for installation.

Comparing OEM and PMA Options

As made clear by the rigid rules that have to be followed to earn PMA, the choice between OEM and PMA products is rarely about quality. Aircraft that are still under warranty or have leasing agreements will likely mandate the use of OEM components, but if you have the flexibility to choose, there are three advantages that FAA PMA parts can hold over the originals: 

• Cheaper Production Costs: PMA products are often cheaper, as their manufacturers inherently avoid the immense research and development costs associated with developing the product from scratch, let alone the type certification of an entire aircraft or engine.
• Broader Availability: OEMs might slow down or completely deprioritize production of older product lines, leading to more scarcity. Even in these events, you can likely avoid significant lead time delays by instead securing PMA items from aircraft spare parts suppliers.
• Engineering and Innovation: Since PMA manufacturers often enter the market after a part has been in service for years, they have the benefit of hindsight. With historical maintenance data, they can attempt to mitigate flaws or wear patterns found in the original design for superior longevity.

Aero Parts Distributor: A Go-to Source for OEM and PMA Parts

The aviation industry depends on aircraft parts suppliers to create a resilient market for maintenance tasks, and thanks to strict oversight, both OEM and PMA entities are perfectly acceptable choices. No matter which you are hoping to source, Aero Parts Distributor has thousands of products available for your consideration. Our entire inventory is sourced from companies that have been thoroughly vetted, and every purchase will be shipped out with any pertinent manufacturer trace documentation and certifications for complete assurance. Alongside our strict quality commitments, we pride ourselves on presenting customers with competitive procurement solutions that take all of their needs into account. To learn more about our parts and services, check out our website and connect with our team today!