What to Know About Supplemental Type Certificates

Can an approved solution—a supplemental type certificate (STC)— void a manufacturer's warranty?

Richard Scarbrough

Thursday, July 18, 2024 at 12:37 PM ET

Verified

Edited By:

Kimberly Johnson

An STC is needed to make a major change to the airplane, such as installing new technology, changing the engine, or updating the interior. [Credit: Adobe Stock]

Key Takeaways:

A Supplemental Type Certificate (STC) is an FAA approval for significant modifications to an aircraft's original design, ensuring the alteration meets safety standards and maintains airworthiness.
While an STC provides legal FAA approval for a modification, it does not automatically imply recognition or authorization from the aircraft's Original Equipment Manufacturer (OEM), potentially raising warranty concerns.
STCs are required for major aircraft changes such as avionics upgrades, engine conversions, or the use of alternative fuels (like G100UL), and involve a rigorous FAA approval process.
STCs serve to standardize modifications, ensure continued airworthiness, and provide essential documentation for alterations, and are utilized by both third-party developers and aircraft manufacturers.

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Recently, following the emergence of a Cirrus service advisory regarding the use of GAMI’s G100UL unleaded aviation gasoline, I was asked, can an approved solution—a supplemental type certificate (STC)— void a manufacturer’s warranty? Isn’t the FAA approval the gold stamp one needs to fly off into the sunset with a clean bill of airworthiness?

Like everything else in aircraft maintenance, it depends.