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:

An STC (Supplemental Type Certificate) 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 legal airworthiness, its use (e.g., GAMI's G100UL fuel) can raise questions about recognition by the original equipment manufacturer (OEM) and potential warranty impacts.
STCs are crucial for documenting, standardizing, and legally approving major changes such as avionics upgrades, engine conversions, or installing new technologies.
Both aircraft manufacturers and third-party companies frequently utilize STCs to implement modifications and adapt aircraft designs for new purposes.

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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.