Swift Fuels has received approval of an ASTM International production specification for its 100R unleaded avgas.
The final voting results from ASTM were published Sept. 4, 2025, after 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,” said company officials.
The approval is for use in Cessna 172R and 172S models with Lycoming IO-360-L2A engines.
Swift Fuels will now work with the FAA to expand the Approved Model List (AML), which company officials say they expect to happen soon. That will allow 100R unleaded fuel to be used in more aircraft and engines in the GA fleet.
“We have completed hundreds of tests with FAA oversight and also with many third-party expert firms,” said Swift Fuels CEO Chris D’Acosta. “We then documented our results to industry and FAA over the past few years.”
This is the third time in 11 years that Swift Fuels has successfully navigated the ASTM process, company officials noted.
The next step for the company is to roll out new sites using the 100R avgas.
“As of today, five U.S. flight schools utilize 100R, as well as five flight schools in the EU (Germany, Belgium, Austria and The Netherlands),” company officials said, adding it “expects to rapidly expand the coverage of 100R at many more sites across the globe in the weeks and months ahead.”
The approval was heralded by general aviation advocates, including the Aircraft Owners and Pilots Association (AOPA) and the National Air Transportation Association (NATA).
“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.
“The approval of 100R for an ASTM International production specification represents another significant step in the transition to unleaded aviation fuel, while strengthening our industry’s commitment to safety,” echoed NATA President and CEO Curt Castagna.
AOPA and NATA are part of EAGLE (Eliminate Aviation Gasoline Lead Emissions), a government industry initiative with the mission to have general aviation lead free by 2030.
For more information: SwiftFuelsAvgas.com
This is starting to sound like a legal battle. Each side brings their own experts and show “their facts”. Of course each fact has a long list of how it was determined details.
Problem is, just as in court with both juries and judges, they are not really well versed in what to believe or understand from the numerous nuanced facts and expert witnesses.
Of course our elected officials and certainly the general public have no clue of what makes any sense on leaded fuels. I will add that even the owners and users of 100LL are not even sure what to make of it.
This will go on likely for many more years. There will be winners and losers, only thing I predict for sure is it will cost more in the future.
If it burns up our valves like it did it at the University of North Dakota will they replace our engines?
Show us the way. Give us a guarantee that this fuel is not going to destroy our engines.
It burned up the valves in the planes at University of North Dakota. They’re done with it.
Hello, Mr. Keller’s comment is “right on” Unleaded fuel for G.A. is the future no getting around. Thanks for publishing his comment.
Robert Germann
Welcome to the Merry Go Round, They are Bound and Determined to ram this down our throats, No Matter What. I think that if these companies are So Sure that their fuel is a drop in replacement with NO engine ramifications they should be liable for burnt valves etc. If they continue to say there are no issues…I say put your money where your mouth is,,, because I do not think its right for the Average GA pilot and Aircraft owner to be the test bed for their fuel which we are paying for to start with obviously and could lead to Huge Maintenance / Overhaul / Repair bills down the road, I find it hard to believe that in the Entire World that the miniscule amount of detriment to the environment from burning 100 LL being taken out of the equation will even make 100.000th of a percent difference. Pretty sure there are a LOT Bigger fish to fry in that Department.
The miniscule amount that you refer to is about one million pounds of lead emissions each year from GA aircraft in the US. Far less than cars left for us, but a bigger fish to those who have children who are breathing it into their lungs. You find it hard to believe because you are quite uninformed about those lead emissions. On the rest of the article, one only needs to follow Curt Castagna to understand what he and EAGLE have not done.
The EPA report on air released lead emissions for 2023 was 333,000 lb total, the majority from mining and industrial emissions.
the lead bromide/ lead phosphate emissions from 100LL combustion exit the exhaust as solid particles, which quickly fall to the ground. So, they do not remain in the air for very long.
The residual lead from the 50 years of autos burning leaded gas are still a substantial source of lead on the ground.
Genau! Wir brauchen eine Garantie, dass der Treibstoff nicht Folgekosten durch abgebrannte Ventile verursacht.
I was at Oshkosh Wisconsin. I asked them how many hours they had on one of the engines. A massive 400 hours. They didn’t have any problems. They haven’t even run one engine up to 2000 hours.
University of North Dakota had problems with this fuel. Burned up their valves. Stopped using it. End of message.
UND ran Swift Fuels’ 94UL for a time. This story refers to Swift Fuels’ 100R.
Why do I think in the end is going to destroy a massive amount of engines?
The UND engines only suffered exhaust valve seat erosion, for unknown reasons.
So, no engines were ‘destroyed’.
I had an exhaust seat erode to the point where the rocker arm was contacting the spring retainer. The engine was running fine. It was a low compression check that cause us to look at the valves.
If any of the UL fuels cause a similar seat erosion, it’s a matter of replacing cylinders.
I don’t understand why people are hung up on an ASTM spec. ASTM does NOT test any fuel in any engine for compatibility or performance. If you pay ASTM enough money they will publish a spec for your product. That is all and ASTM spec means.
” … to expand the Approved Model List (AML)…”
So much for ASTM declaring 100R to be a “drop-in replacement” …
Wonderful! Now, to which ASTM specification does Swift’s 100R fuel find compliance? Lycoming Service Instruction 1070AB will list the appropriate options in Table #1 and Table #3.