The general aviation industry faces safety and legal hurdles during the transition to 100-octane unleaded fuel. Understanding the discrepancy between test-engine octane ratings and real-world engine performance is vital for maintaining safety and protecting manufacturers from liability.
unleaded fuel
A Single Specification
Forget ASTM or the STC process: Maybe it’s time to look at a specification for unleaded avgas in a whole new way.
Deep Pockets
A number of issues remain affecting general aviation’s transition to unleaded avgas. Perhaps the most important is the three companies working on the solution lack “deep pockets” in a very litigious society.
Make Your Voice Heard on The Transition to Unleaded Fuel
You have until March 13, 2026, to comment on the FAA’s draft Transition Plan to Unleaded Aviation Gasoline.
Can General Aviation Transition to Unleaded Avgas by 2030?
As our fuels and oils expert looks back at what was accomplished in 2025 towards general aviation’s transition to unleaded fuel, he questions whether we can meet our self-imposed deadline of 2030 to go completely lead-free.
UL100E advances in race to unleaded avgas
The American Society for Testing and Materials has published its first specification for UL100E, an unleaded aviation fuel co-developed by LyondellBasell and VP Racing. This milestone brings the fuel one step closer to fleetwide authorization as it continues full-scale evaluation under the FAA’s Piston Aircraft Fuel Initiative (PAFI) program, with testing expected to conclude by late 2026.
Blame it on the lawyers
When there is a problem with the transition to unleaded avgas, maybe those affected will sue the EPA or the FAA. But more realistically they will sue everyone from the airplane manufacturers to the fuel distributor, letting the courts sort it out to determine the winners and losers.
New toolkit offers insight into transition to unleaded fuel
The new interactive toolkit, available at flyEAGLE.org, offers regularly updated insights into the U.S. piston fleet, fuel infrastructure, airport fuel availability, 100LL production and logistics, sales volumes, per-capita data, and more.
Court claims GA still doesn’t have a commercially available unleaded avgas
Judge S. Raj Chatterjee noted in the May 30, 2025, ruling that since G100UL has not gone through the ASTM process for specification, it cannot be considered “commercially available.” But the folks behind the unleaded fuel have something to say about that.