FAA Broadens Eligibility for Swift Fuels 100R Unleaded Avgas to Over 1,600 Aircraft Models

Swift Fuels announced on Tuesday that the Federal Aviation Administration has greatly expanded the list of piston aircraft eligible to use its 100R unleaded aviation gasoline. This expansion, applied through updates to the fuel’s Supplemental Type Certificate, adds more than 1,200 engine models and 1,600 airframe models. The move is a significant milestone in reducing the piston fleet’s reliance on leaded 100LL avgas by the end of the 2020s.

The expanded Approved Model List now includes engines from more than 80 manufacturers, with a detailed breakdown highlighting approximately 395 Lycoming, 195 Continental, 95 Curtiss-Wright, and 95 Pratt & Whitney engine models. On the airframe side, the update also covers more than 1,600 aircraft models, including about 118 Cessna, 101 Beechcraft, and 98 Piper models. Additional approved airframes come from Mooney, Grumman, Stinson, WACO, and Fairchild, among others.

This addition to the STC means that aircraft owners and operators representing roughly 56 percent of current U.S. consumption of 100LL avgas now have the regulatory clearance to transition to Swift Fuels’ 100R. This phase constitutes the first step in Swift’s broader certification plan, signaling a systematic approach to expanding unleaded avgas usage throughout the piston fleet.

The company expects further certification rounds in Phase II and Phase III, scheduled through 2028, to add higher-performance engines and airframes that remain uncertified. These steps are part of ongoing efforts by the FAA and industry stakeholders to progressively replace leaded avgas in piston-powered aviation.

Swift Fuels emphasizes that 100R remains the sole commercially available 100-octane unleaded avgas meeting both FAA-approved Supplemental Type Certificates for eligible aircraft and ASTM International’s D8603 production standard. Use of this fuel requires aircraft owners to obtain the corresponding STC, ensuring compliance with certification requirements.

For those who previously acquired the company’s UL94 STC, Swift Fuels offers automatic transition to the 100R STC under its Forever STC program at no additional charge. This policy facilitates easier adoption of the new unleaded fuel and supports fleet modernization efforts without imposing extra cost burdens on owners.

Commercial sales of 100R have been ongoing for nearly two years across five airports each in the United States and Europe. Now, distribution is expanding, with the initial transition from UL94 to 100R slated to begin this summer at participating U.S. airports spanning 29 states, including California, Colorado, Arizona, Florida, Minnesota, Utah, and Wisconsin. The international footprint has also grown to include airports in Canada, Australia, Germany, France, Austria, the United Kingdom, and the Netherlands.

Certification work continues collaboratively among the FAA, Swift Fuels, and engine manufacturers to bring the remaining high-performance piston engine fleet into compliance with unleaded fuel operation. Additional approvals are planned for 2027 and early 2028, extending the environmental and operational benefits of 100R to an even broader base of piston aircraft.

The FAA initially approved Swift Fuels’ 100R STC in September 2024, marking the regulatory groundwork upon which these recent expansions build. With these latest updates, Swift Fuels advances the nation’s flight departments and general aviation community toward a safer and cleaner piston aviation fuel environment.