FAA Confirms that No Other Avgas Meets the Criteria to Replace 100LL

In case there was any lingering ambiguity, the FAA has now made it crystal clear: federally funded airports cannot restrict access to 100-octane low-lead avgas (100LL). Unless, of course, they’d rather violate federal law and potentially pay $5,000 per day in penalties.

The clarification comes in the form of a Q&A released May 19, 2025, by the FAA’s Office of Airports. It interprets Section 770 of the FAA Reauthorization Act of 2024, which created Grant Assurance 40: a requirement that prohibits airports from banning or limiting the availability of 100LL until an FAA-approved, industry-accepted unleaded replacement fuel is both available and authorized for all aircraft.

And here’s the kicker—despite all the discussion, no such fuel currently exists. As of April 2025, the FAA confirms that none of the promising unleaded high-octane fuels on the market meet the legal criteria. Until that changes, 100LL remains the only game in town.

“For example, a fuel would have to be authorized for all aircraft and no fuel has been authorized for the rotorcraft fleet,” the statement read. “The FAA will provide additional information when the criteria is met.”

The Q&A also outlines what airports cannot do, including quietly revising rules, fees, or lease terms in ways that make it harder to access or sell 100LL. Even attempts to restrict self-fueling or impose local codes designed to discourage its use are off-limits. All of it counts as noncompliance under Grant Assurance 40.

The FAA says it will prioritize education and outreach, but reserves the right to conduct oversight and investigations. For those who don’t cooperate, civil penalties are on the table. And while the agency acknowledges the long-term goal of removing lead from avgas, it’s sticking with a methodical approach grounded in certification and safety instead of wishful thinking.

So for now, if your airport sold 100LL in 2022 and took federal dollars, your options are limited. Until an approved unleaded replacement exists, 100LL stays.

FMI: www.faa.gov