Unleaded 100R Fuel Clears ASTM Approval

Unleaded aviation fuel takes step closer to broader adoption

Fueling a GA aircraft
[Credit: FAA]
Gemini Sparkle

Key Takeaways:

  • Swift Fuels' 100R unleaded aviation gasoline received ASTM International approval, a crucial step for wider adoption.
  • This approval establishes a standard for the fuel, facilitating FAA certification for use in more aircraft beyond the currently approved models.
  • The approval follows extensive testing with FAA oversight and collaboration with various aircraft manufacturers and engine producers.
  • This development is a significant advancement in the aviation industry's transition from leaded to unleaded aviation fuel.
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Swift Fuels has secured ASTM International approval for its 100R unleaded aviation gasoline, a move industry leaders describe as a key milestone in the transition away from leaded avgas. 

ASTM is a standards organization that sets safety, quality and performance specifications for fuels and other products. Approval by the organization helps to provide the FAA and other entities a recognized benchmark against which to certify new fuels for use in aircraft.

Indiana-based Swift announced this week that ASTM issued a global production specification for 100R, clearing the way for FAA action to expand its Approved Model List beyond Cessna 172R and 172S models with Lycoming IO-360-L2A engines.

“This is the culmination of several years of dedicated research by the team from Swift Fuels working in collaboration with FAA and numerous OEMs,” the company told AOPA, noting contributions from Lycoming, Continental, Rotax, Textron, Piper, and others. 

Swift Fuels CEO Chris D’Acosta added that hundreds of tests were conducted with FAA oversight and third-party experts, producing data the agency can now use to approve additional aircraft and engine combinations. 

“Many more aircraft are expected to be FAA-certified soon,” said D’Acosta.

Industry groups welcomed the approval. 

“AOPA has long supported the development and deployment of safe, reliable unleaded fuels, and this achievement is a positive step in that direction,” said AOPA President and CEO Darren Pleasance. 

Swift Fuels already supplies 100R to a small number of flight schools in the U.S. and Europe, but ASTM helps pave a simpler path forward for wider distribution following expanded FAA certification.

Matt Ryan

Matt is AVweb's lead editor. His eyes have been turned to the sky for as long as he can remember. Now a fixed-wing pilot, instructor and aviation writer, Matt also leads and teaches a high school aviation program in the Dallas area. Beyond his lifelong obsession with aviation, Matt loves to travel and has lived in Greece, Czechia and Germany for studies and for work.

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Replies: 1

    1. This fuel cannot be combined with G100UL without (apparently) risking damage due to how the octane-enhancing ingredients interact (they can each be combined with 100LL). That sounds like a recipe for disaster.
    2. STC process? Really? How did this become the norm? How is it that different blends of 100LL can be marketed without an STC but lead-free avgas can’t? It’s completely impractical to expect facility operators to have a fuel pump and limit its use to people with STCs (which, among other things, would block all Experimental, Light Sport and MOSAIC aircraft, none of which have Type Certificates).
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