OEM or PMA Aircraft Parts: What’s the Difference?

Last year on July 20th, there were 54,150 flights crisscrossing the United States. This was the busiest day of the year for the FAA.

The FAA regulates more than the aircraft in the air. They also regulate the aircraft engine parts and production that goes into them.

There has long been a debate over whether you should buy OEM or PMA parts. This is partly because of no longer relevant beliefs about the safety of PMA parts.

We are going to set the record straight on their price, quality, and regulation.

Certifications Given to Aircraft Parts

The FAR Part 21 regulates the production of airplane components. There are a few different types of approval a part is eligible for.

PMA Aircraft Parts

Parts manufacturers get a PMA certificate to produce aircraft parts that they are not the original manufacturer. This is like aftermarket parts manufacturers in the auto industry.

The FAA regulates who can produce parts. A manufacturer must apply to the FAA for approval. There are three methods that can give PMA certification.


For this method, the manufacturer applies to the FAA showing their part is identical to the OEM part. The easiest way to prove identicality is through licensure.

The manufacturer will show that they licensed the part from the OEM. Sometimes the OEM will provide documentation confirming this.

Test & Computation

This method uses general and comparative analysis. The general analysis compares the functional needs of the new part to the original one.

The comparative analysis looks at the functioning of the part as compared to the original one. The FAA Aircraft Certification Office (ACO) performs the tests. A determination of compliance is then issued.

Production Approval

A PMA meaning is not complete without the product approval process. Once the part gets determined as identical, it needs to pass production approval.

This approval comes from the FAA Manufacturing Inspection Divisional Office (MIDO). This part of the process checks the manufacturing process. Only complying parts should make it to the marketplace.

A company with Production Approval Holder (PAH) already has production approval before applying for PMA. PAH approval goes to the manufacturer while PMA approval is for parts.

Identifying a PMA Part

Each PMA part produced by a PAH must have “FAA-PMA” stamped on it. The PMA must also include their name, trademark, and FAA ID and part number.

All markings need to have some sort of permanency. The best practices have this information stamped into the part.

If the part is too small to have a mark then an attached tag will have the information. If this is still impractical, the tag can refer to a manual or database for reference.

OEM Aircraft Parts

OEM stands for Original Equipment Manufacturer. These are like the OEM parts that auto manufacturers produce.

At the beginning of aviation, OEM aircraft parts were the only option. This was because the manufacturer made the plane, so they had the ability to make the parts.

Type Certificate

The holder of a type certificate is the OEM. Only OEMs can produce parts under this certificate.

The certification for the part is easier under this certification. It references the OEM’s application of airworthiness for the aircraft. Since the OEM proved the part was safe in the approval of the overall craft.

Production Type Certificate

Any manufacturer with this certificate can produce a part with FAA approval. The approval lasts for up to 6 months after issuance. This requires the FAA to regulate the manufacturer for assurance of compliance.

Technical Standard Order

The FAA issues a Technical Standard Order or TSO. It is a regulation for the minimum performance standards.

These apply to parts, materials, and appliances on civil aircraft. These written orders will outline the parameters for input, output, and operating.

Any other minimum operating requirements are also included. TSOs get issued publicly.

This aids the FAA in developing a uniform standard of performance. The FAA makes issued TSOs available on their website.

Technical Standard Order Approval

An often confused acronym is TSOA, which stands for Technical Standard Order Authorizations. This is when the FAA gives their approval to produce a part or material.

When a part receives approval, it is for both design and production. To receive this approval, a manufacturer must show two things in their application.

They must show that the design of the part meets the TSO minimum standards. They also need to prove there is a manufacturing system in place. This ensures each part produced meets minimum standards.

No Installation Authority

The difference between PMA and TSOA is that the TSOA does not give installation approval. A PMA gives installation approval for a specific aircraft.

A TSOA gives minimum standards of performance in a wide variety of aircraft. The FAA gives approval based on whether the part is a minor or major change to the aircraft.

The Price Difference

It is a common misconception that items that are more expensive must be of better quality. This way of thinking is not limited to the aircraft industry.

Go to a mall or grocery store and you’ll see people choosing name brand products. They think these brands are better quality than their off-brand alternatives.

In other industries, there is debate over which ones are better. The has worked hard to make this a non-issue for the aviation industry.

The FAA holds all parts to the same quality and safety standards. This means that the part will perform as expected no matter what you’ve paid for it.

Unfortunately, the FAA did not always regulate the aftermarket parts as they do today. This has led some to have carried over beliefs from a different time.

Marketing Efforts of OEMs

For years OEMs enjoyed a monopoly over the market. They had the ability to price their parts as high as they chose.

Airlines and private enthusiasts had no choice but to pay the OEM. Due to demand the OEMs were often back ordered on the parts that were popular.

When the PMA industry grew, OEMs stressed that their products were superior. They would also imply that PMA parts were not as safe.

OEMs would include marketing to imply that alternatives were not as good. Some went so far as to suggest they would not honor their warranties on the entire plane.

Marketing Efforts of PMAs

Many airlines prefer PMAs for more than the price. Many PMA manufacturers saw the opportunity to provide a service.

They made a point to have parts available when requested. This addressed the long back order times historically known to happen with OEMs.

Excellent customer service such is another service the PMAs have thrived in. The large OEM suppliers tended to get tied up in red tape. While the smaller PMA manufacturers had the ability to move and responded at a moment’s notice.

History of Aftermarket Aircraft Parts

The first demand for non-OEM parts came after WWII. Enthusiasts took an interest in defunct military planes.

These private pilots wanted to repair and bring life back to these no longer used planes. The problem was that the OEM companies were no longer producing the parts needed.

If they were producing the part, it was expensive for the enthusiasts. Smaller independent manufacturers began to appear to supply this need.

PMAs Enter the Market

The 1950s saw the beginnings of regulation with the Civil Aeronautics Board. It wasn’t until 1965 that the CAR became the Federal Aviation Regulation.

This was also the year that the CAR began imposing safety standards on PMAs. This new regulation was the Fabrication Inspection System.

New Regulations

It wasn’t until the 1970s and 80s when stricter regulation began. With this change, PMAs could no longer depend on the data of the OEM for approval. They needed to submit their own data.

The problem came in when the PMA market grew in the 80s thanks to airlines looking to cut costs. Many PMAs failed to get approvals from the FAA.

A New Era of Safety

An “Enhanced Enforcement” program in the 90s brought about a shift in the PMA industry. The FAA undertook initiatives to educate the industry and get parts approved.

PMAs who had not previously applied for approval were able to get their parts approved. This brought many manufacturing facilities into full compliance.

These new regulations also brought a boom in the formation of PMAs. The increase in PMAs brought new competition and a bigger market for the OEMs to compete with.

The 2008 FAV Report on Repairs, Alterations, and Fabrications of Parts

In 2008 the FAA issued a special bulletin on the airworthiness of PMA parts. The FAA stated this was a result of OEM actions.

Both the FAA and MARPA wanted to encourage the PMA industry. Both also wanted to stop the marketing campaign by OEMs to discredit PMA parts.

OEMs and TC holders claim they requested that the FAA perform an investigation of PMA parts. It was their belief that these parts were unsafe.

The Federal Aviation Administration performed the investigation. The research included the repair, alteration, and fabrication of PMA parts.

The bulletin clarified that OEM manufacturers could not back out of their responsibilities. The FAA confirmed OEMs could not back out of warranties because a PMA part got installed.

A major proponent of stopping the OEM statements was MARPA. MARPA stands for Modification and Replacement Parts Association.

This trade association represents the PMA industry. They would with the FAA to promote PMAs and their safety.

This research also brought a new issuance of regulations for the industry. These new regulations came a year later in 2009.

The 2009 PMA FAA Rule Change

In 2009 the FAA published a major overhaul of the US manufacturing regulations for the aviation industry. This changed the legal distinctions between the forms of production approval.

This, in turn, changed the PMA meaning and the governing body. The change brought regulations into alignment making them clearer to applicants.

These new rules went into effect in 2011. Now complete aircraft and parts have the same set of quality standards.

International Parts

Thanks to Bilateral Aviation Safety Agreements (BASA) international parts get treated as FAA-PMA. This makes them importable and usable for aircraft registered in the United States.

The PMA industry began in the United States. These agreements have allowed the industry to grow in Australia, China, and The European Union.

Other countries are currently working on building their own PMA regulations. Japan is the latest to secure a bilateral agreement with the United States for parts.

Fabricated Parts

Enthusiasts can expect the FAA to come out with findings on parts fabricated during a repair. Historically these parts have cause confusion with PMA manufactured parts.

These are different from PMA parts as they are purely for maintenance operation. A part that gets fabricated in a shop or by a mechanic becomes a fabricated part.

This part is never intended for individual sale. These specialized parts have a different set of regulations with the FAA.

The future will see the FAA releasing recommendations for a quality assurance system. This system will be like the fabrication inspection system that a PMA complies with.

Aircraft Engine Parts

Thanks to the FAA, buyers have the option of choosing either OEM or PMA aircraft engine parts. Both manufacturers get held to the same design and production standards.

While this wasn’t always the case, a regulations overhaul that went into effect in 2011 has changed this. These new regulations have clarified the approval process.

Today you can confidently shop for aircraft parts knowing they are safe. The future of the industry looks bright with international agreements developing.

When you are shopping for used or salvaged parts, look for an identifying mark on the part. This will help you ensure the FAA has approved the part for safety.

Let us help you keep flying by finding the parts you need for your aircraft.