The approval effectively means the GAMI Supplemental Type Certificate (STC) can be used in any aircraft engine in the current GA fleet that uses spark plugs, and addresses the demand in the USA to remove lead from avgas.

"This is a big day for the industry," said GAMI co-founder George Braly. "It means that for a lot of our general aviation communities, and especially for the high fraction on the West Coast, relief is on the way.

"And it means our industry will be able to go into the future and prosper, and provide the essential infrastructure for this country from everything from Angel Flights to critical training of our airline pilots."

GAMI was initially issued with an STC in July 2021 for G100UL use in certain Lycoming O-320, O-360 and IO-360 piston engines. This broader acceptance for any engine is expected to lead to a wider adoption of unleaded fuel in the USA to satisfy the demands of the US Environmental Protection Agency.

The FAA first established a team to develop a drop-in solution for unleaded avgas in 2011, with the aim of having it widely available by 2018. However, only a few years into the project, the FAA began to think it may be technically impossible to achieve.

"I am proud of GAMI, the industry team, and the FAA for persevering over the long term and getting a fuel that the FAA has recognised as a viable alternative to low lead," AOPA USA president Mark Baker said yesterday.

"It's vital that we find solutions to what has been plaguing general aviation since the seventies. It's certainly the biggest issue I have dealt with in my time at AOPA.

"This is a big deal, but there is a lot of work to be done yet."

GAMI is yet to sign distribution deals for G100UL and expects to produce it initially in small batches, targeting especially the California market where some municipalities have already banned the sale of leaded avgas.

General Aviation Manufacturers Association president Pete Bunce said that GA aircraft manufacturers welcomed the news of the wider STC.

“As we continue to work towards a safe and reliable transition to an unleaded future state for piston-engine aircraft, FAA issuance of a broader STC for GAMI’s G100UL is a significant milestone," he said.

"Manufacturers look forward to having an opportunity to understand the composition and performance of this new fuel to support commercialization and use as a viable replacement for 100LL.”

G100UL is not currently available in Australia, but CASA is not expected to stand in the way of the STC being applied here once supplies reach our shores in commercial quantities.

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