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 and airworthiness standards.
While an STC provides FAA-approved legal airworthiness, its use may not always be recognized or authorized by the aircraft's Original Equipment Manufacturer (OEM), which can raise questions about warranties.
STCs are vital for major aircraft changes like avionics upgrades or engine conversions, and are developed by both third-party entities and sometimes the OEMs themselves.

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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.