FAA expands Swift 100R unleaded approval

The expansion of the Swift 100R STC and AML was first reported by Aviation Week, including references to a 2025 timeline published by the Indiana company that additional approvals for larger, high-compression engines are being sought: "On a separate path but in parallel with this work, Swift Fuels will be seeking to certify a slate of engines and aircraft representing higher-octane, BMEP (Brake Mean Effective Pressure) and compression ratio group we call the '550-Series' which includes the Continental TSIO-550-K and the naturally aspirated IO-550-N engines and many similar engine configurations," the company wrote in a white paper prepared for EAA AirVenture 2025.

Swift Fuels CEO Chris D'Acosta wrote in a March 20 email response to questions that progress toward the company's 2025 target dates was delayed by the October government shutdown and subsequent holidays, though announcements will be forthcoming "when more relevant Swift Fuels certification information is 'market ready' in a broader context."

D'Acosta noted that Swift unleaded fuels (including the company's long-approved UL94 blend) are being sold at more than 100 airports in six countries, with more than 5 million gallons delivered to date.

"Thus, I prefer to orchestrate our market announcements once we have more features ready to distribute to that broader audience," D'Acosta wrote. "That said, we are certainly pleased to have received FAA approvals on our STC/AML list for 840 piston engine models…. But, there will be many more to come later this year."

Swift 100R is among three rival 100-octane unleaded blends that have entered service, or are on the brink. General Aviation Modifications Inc. gained a fleetwide STC for G100UL in 2022, but distribution remains limited to a handful of airports. LyondellBasell and VP Racing hope to gain fleetwide approval for their 100-octane formulation later this year, having secured a test specification from ASTM International in November. That fuel is the only remaining candidate in the long-running FAA Piston Aviation Fuels Initiative, which includes testing by the FAA. PAFI was created to pursue certification of a fleetwide replacement for 100LL.

Swift Fuels announced publication of its ASTM production specification for 100R in September. While an ASTM specification, which requires independent evaluation of the fuel in question, is not required by the FAA, it enhances the fuel's marketability and is viewed favorably by regulators. Swift began distributing 100R to select flight schools in November 2024, which has created a body of real-world experience running 100R in Cessna 172R and -S models under the original 100R STC that the FAA updated on March 11.