Swift Fuels' 100-octane unleaded aviation fuel granted first STC

The STC granted to Swift Fuels on September 6 and allows 100R unleaded avgas to be used in Cessna 172 Skyhawk models R and S with Lycoming IO-360-L2A engines.

Although this STC represents only two aircraft and engine combinations, Swift Fuels CEO Chris D’Acosta said that the company plans to seek additional STCs with the goal of becoming the global replacement for 100LL within three to five years.

“We’re following a very similar approach where we approve a certain set of engines and airframes and then we expand from that, just like we did nine years ago with UL94,” D’Acosta said. “It’s exactly the same architected program except that’s it’s for the 100-octane fuel. We emphasize our work with OEMs, with the FAA, and with the ASTM international experts; those are all people we collaborate with.”

D'Acosta did not disclose which airframe and engine configurations are next in the STC approval process but stated more progress is expected soon.

There are currently two other unleaded aviation fuel manufacturers seeking to produce and widely distribute unleaded fuels that can replace avgas.

General Aviation Modifications Inc.’s G100UL received STC approval for use in certain Cessna 172 engine/airframe combinations in 2021, followed by another STC in 2022 that allows G100UL to be used in every spark-ignition piston engine in the fleet.

Unlike Swift, GAMI declined to submit G100UL for ASTM certification, and that is among the factors delaying its industry acceptance and distribution.

UL100E, developed by LyondellBasell and VP Racing Fuels, is currently undergoing engine and airframe testing through the FAA’s Piston Engine Aviation Fuels Initiative, with hopes of receiving fleetwide approval in 2025.