FAA Plans Unleaded Fuel Comparison Testing - AvBrief.com

The FAA plans to conduct head-to-head tests of three unleaded candidate fuels to replace 100LL aviation gasoline by Dec. 30, 2030 (2032 in Alaska). The tests will compare GAMI G100UL, Lyondell/Basell UL100E, and Swift Fuels 100R against 100LL formulations for detonation, materials compatibility, and fit-for-purpose capabilities. The FAA will also test the mixing qualities of the unleaded fuels on common aircraft engines. The transition to unleaded fuel is expected to be completed by 2027, with market experience informing any changes. The FAA is considering options beyond engine modifications, such as electronic ignition, anti-detonation injection systems, hybrid electric propulsion, or replacing spark-ignition piston engines with compression-ignition engines. The public is invited to comment on the proposals until March 13, 2026.