B Carey, The FAA eyes unleaded options as milestone looms, AviationWeek & Space Technology, 14-27 July 2025, p 48

In US, the FAA has tied airport grant applications to the availability of unleaded Avgas through 2030. General Aviation Modification Inc.’s G100UL received FAA supplemental type certification approval in 2022, but not yet from ASTM by lacking a production specification. Swift Fuels’ 100R is also under review, together with LyondellBasell & VP Racing UL100E.