Swift 100-octane unleaded meets ASTM specification
Now up to FAA to expand AML
Swift Fuels CEO Chris D'Acosta told Congress in August 2022 that his company would earn fleetwide approval of its 100-octane unleaded aviation fuel within three years, and on September 4 announced a major step toward achieving that ambitious goal: production of 100-octane unleaded aviation fuel meeting the requirements of a new specification published by ASTM International.
The Indiana company announced the ASTM production specification approval in a press release.
"This is the culmination of several years of dedicated research by the team from Swift Fuels working in collaboration with FAA and numerous OEMs from Lycoming, Continental Aerospace, Rotax, Textron Aviation, Piper, and others, plus testing laboratories and various aviation part suppliers," the company noted in the news release. "Members of the ASTM voting committees represent several hundred companies from around the world including major international oil companies plus fuel experts and representatives from military and civilian entities."
The approved global production standard could support approval to use the fuel in specific aircraft by the FAA and its international counterparts. D'Acosta noted in an email exchange that the ASTM process includes engine and aircraft manufacturers, as well as companies throughout the supply chain that participated in a peer review process, the completion of which gives the FAA a basis to approve the fuel for additional aircraft and engine combinations.
The FAA granted supplemental type certificate approval for Swift 100R in 2024 that allows the fuel to be used in Cessna 172 R and S models with Lycoming IO-360-L2A engines, at which point D'Acosta said additional STCs would allow 100R to replace 100LL in the next three to five years. While D'Acosta's 2022 prediction to Congress of fleetwide approval by 2025 may slip a bit, the ASTM publication may accelerate FAA action to expand 100R approval to additional aircraft and engine combinations.
"Many more aircraft are expected to be FAA-certified soon," D'Acosta wrote.
General Aviation Modifications Inc. earned a broad STC in 2022 authorizing the use of G100UL in all piston airplanes, though GAMI has opted not to submit its product for transparent, independent testing by ASTM, or through the FAA Piston Aviation Fuels Initiative. A lack of such review has been cited by industry leaders as cause for reluctance to distribute G100UL, which has been associated with fuel system leaks and aircraft staining that may be the result of new fuel formulas being introduced to aircraft with decades-old fuel system components. Jeff Simon, an A&P mechanic with inspection authorization and AOPA contributor, explained the issue in detail in a recent column, including advice on what aircraft owners can do to prepare for the arrival of unleaded fuels—all of which contain higher aromatic content than 100LL.
A California judge also noted the lack of general G100UL approval in a ruling this year against an environmental group's effort to force the exclusive distribution of G100UL across California.
The Eliminate Aviation Gasoline Lead Emissions initiative called attention to an FAA special airworthiness information bulletin in April, as the FAA asked aircraft owners to report their experience with unleaded fuel (of any brand).
Swift is currently supplying 100R to five U.S. flight schools and another five in Europe, though it has not been sold to the public pending the approval of an ASTM specification. D'Acosta noted in his email that the ASTM publication removes the barriers to selling the fuel, though further FAA action is required to make more customers' aircraft eligible to use the fuel.
