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 it meets safety and airworthiness standards, but it doesn't automatically guarantee the manufacturer's endorsement or warranty validity.
STCs are crucial for legal and safe aircraft operation, providing standardization, confirming airworthiness, and formally documenting major changes like avionics upgrades, engine conversions, or new technology installations.
STCs are utilized by both third-party entities (e.g., for G100UL fuel or Starlink installations) and aircraft manufacturers (e.g., for converting passenger jets to cargo carriers) to adapt or update aircraft functionalities.

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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.