The FAA Just Set a Date to End Leaded Fuel in American Aviation

On July 30, 2026, the FAA released the final version of its Transition Plan to Unleaded Aviation Gasoline, the roadmap for moving the US piston fleet off 100LL. The 72-page document keeps the target that industry and government agreed on years ago: no leaded avgas in the lower 48 after the end of 2030.

Alaska gets two extra years, until the end of 2032, because of its fuel distribution challenges and its unusual dependence on piston aircraft for basic transport.

“The transition to unleaded fuel is a positive step forward for the general aviation community and people who live and work near general aviation airports,” FAA Administrator Bryan Bedford said in the agency’s announcement.

What the plan actually says

The plan responds to a requirement written into the 2024 FAA Reauthorization Act, and follows a draft the agency put out for public comment in January 2026. The FAA says it will publish a supplemental document summarizing those comments later this year.

It splits the job into four phases. Phase 1 covers fuel authorizations and side-by-side comparison of the three candidate replacements. Phase 2 puts those fuels into real-world use to gather operational experience, and the FAA projects it running through mid-to-late 2028.

Phase 3 is the national changeover outside Alaska, targeted for completion by the end of 2030. Phase 4 covers Alaska on the longer timeline. Detailed schedules for the last two phases are not set yet; the FAA says it will publish them after Phase 1 wraps up in 2027.

Three fuels are in contention: GAMI’s G100UL, which already holds broad supplemental type certificate approval and is turning up at more airports; Swift Fuels’ 100R, which recently cleared an ASTM production specification; and LyondellBasell/VP Racing’s UL100E, still working through FAA fleet authorization testing.

Why one fuel is hard to replace

Roughly 170,000 piston-engine general aviation aircraft are registered in the United States, and most of them burn 100LL. That is a very different fluid from what airliners use, and avgas and jet fuel are not interchangeable: turbine engines run on kerosene, while piston engines need high-octane gasoline that resists detonation.

Tetraethyl lead is what buys that octane. A trainer like the Cessna 172 Skyhawk would tolerate a lower-octane fuel without complaint. The high-compression, turbocharged engines in a minority of the fleet would not, and those aircraft fly a disproportionate share of the hours and burn a disproportionate share of the fuel.

That is why the industry has spent more than a decade chasing a single drop-in fuel that every engine can burn rather than simply lowering the octane and moving on.

What changes for aircraft owners

Switching a certified aircraft to an unleaded fuel is not a matter of pulling up to a different pump. Under the STC route, it takes a mechanic’s sign-off, a logbook entry, a new placard at the filler, and an amendment to the aircraft’s operating handbook. Some airframes and engines may need hardware changes as well.

The bigger open question is who picks the winner. The FAA’s plan leaves the choice to the market, and the agency acknowledges that incompatible products could split the country into regional fuel markets and raise the risk of misfueling.

Not everyone is comfortable with that. Speaking at an AirVenture forum, AOPA acting co-president Katie Pribyl said the plan “assumes right now that the market is going to decide, and that’s probably not realistic,” arguing the FAA is better placed to help the industry converge on one fuel.

The timing lands in an unusually busy stretch for general aviation rulemaking, coming days after the FAA’s MOSAIC light-sport rules took effect. Both are attempts to modernize a corner of aviation that has been running on decades-old regulatory assumptions.

For now, nothing at the pump changes. 100LL stays available at most airports, and the requirement to keep supplying it holds until the end of 2030 or until an approved replacement is actually on the field, whichever comes first.