After more than three decades of research and development, general aviation finally has an approved unleaded 100-octane fuel. At AirVenture on Tuesday

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2021-07-28 12:00:09

After more than three decades of research and development, general aviation finally has an approved unleaded 100-octane fuel. At AirVenture on Tuesday, the FAA formally awarded a supplemental type certificate (STC) to General Aviation Modifications Inc., the Ada, Oklahoma, company that itself spent more than a decade developing a fuel it calls G100. The fuel would be a drop-in replacement for 100LL which, despite lead content, continues to be manufactured under ongoing dispensation from the Environmental Protection Agency. But it may be quite some time before the fuel is fielded in volume and GAMI says it will probably cost 60 to 85 cents more than 100LL does now.

The STC comes after GAMI development work that started in 2009. It approves the use of G100 in just one type of aircraft, the Lycoming-equipped Cessna 172s. GAMI’s George Braly said that after some additional testing, the STC will be expanded to eventually cover the entire general aviation fleet, although the timing for that expansion remains unclear, as does how the fuel will be fielded in a market that continues to be driven by 100LL. GAMI says the expansion may occur in nine months to a year. Braly said GAMI has an agreement to distribute and manufacture G100 through Avfuel, a nationwide supplier that delivers about 40 percent of piston aircraft fuels to the U.S. market.

Volume manufacturing details remain to be worked out. Currently, 100LL is believed to be manufactured in about five U.S. refineries owned by Phillips, Chevron and Exxon. While Shell markets 100LL in the U.S., it no longer owns its own refineries to produce the fuel in the U.S. It does produce 100LL in Europe and it brands fuel it sells produced by other refiners. Chemically, G100 is a blended fuel consisting of a high-octane alkylate and a proprietary aromatic additive package that boosts the octane to a level equal to or higher than 100LL. As such, it can be produced in any refinery or facility capable of receiving the components by rail or by any refinery currently manufacturing 100LL.