FAA Asks For User Input On High-Octane Unleaded Fuel

In conjunction with the Eliminate Aviation Gasoline Lead Emissions (EAGLE) initiative, the FAA announced today it is calling on pilots, aircraft owners, mechanics and fixed-base operators (FBOs) to document and report their experiences with “a new, high-octane unleaded aviation fuel available at various airports across our nation.” Though not named in the announcement, presumably that refers to General Aviation Modifications Inc.’s (GAMI) G100UL fuel. The high-octane drop-in replacement candidate for the current 100 low lead (100LL) fuel is controversial, largely due to GAMI’s refusal to participate in an ASTM test program, which GAMI claims exposes the company to theft of intellectual property, among other issues it has with the testing.

G100UL has received an FAA Supplemental Type Certificate and is available at select airports in California, Mississippi and at Round Rock Airport (KRFG) in Texas. The FAA has issued a Special Airworthiness Information Bulletin (SAIB 2025-04 copied below) with instructions on how to report detailed experiences with the fuel—both good and bad. EAGLE cochair Curt Castagna said, “Pilots, owners, maintainers, and FBOs across the country are on the front lines of the shift to unleaded fuel. These experiences and reports are essential to validating safe alternatives and identifying potential challenges early. We urge everyone flying or servicing aircraft on unleaded avgas to share their experiences—it’s how we ensure a smooth and successful transition for the entire industry.”

FAA’s EAGLE cochair Caitlin Locke said, “The reports we receive will directly inform our oversight, help us distinguish between unrelated mechanical issues and fuel-related concerns, and ultimately support the safe shift of the piston-engine aviation fuel supply.”