Time to Get Serious About Unleaded Fuel

Because of the way the U.S. government operates, particularly under the Clean Air Act of 1970, certain processes within the associated agencies, including the FAA, could not begin without the finding.

Now leadership from within the industry’s manufacturers, distributors, associations, and users (that’s us, the pilot community) can act on the commitment to getting the lead out of our avgas—specifically the high octane fuel required by high-performance piston engines currently served by 100LL.

But what happens now? I spoke with Walter Desrosier, vice president of engineering and maintenance for the General Aviation Manufacturers Association, this week about the finding and what it triggers. “We have significant progress,” said Desrosier. “There is a broad, collective community commitment from the entire GA industry in cooperation with the government and the FAA to move to no lead. So the EPA action that came out is part of that transition process. It actually puts into the Clean Air Act process how they will mandate a transition. So this is not something that we continue to talk about, that we hope to find solutions—this is a commitment  from the industry that continues to work towards the best solutions.”

The timeline has officially begun, but it will take a couple of years for the mandate and the associated guidance to come into play. In the meantime, the industry is already working hard toward fielding the solutions.

Those solutions include four candidate fuels in the works from different providers in varying states of development, testing, and acceptance. “Part of our transition will also be what’s the best available fuel,” said Desrosier.

By most measures, the furthest along comes from GAMI Inc., whose G100UL has attained supplemental type certification from the FAA. GAMI works with at least one producer, VTOL, to manufacture the fuel in enough quantity to reach those who need to test it and develop its distribution in the field. The STC means the FAA considers the fuel safe for the applications covered in that approval.

While the STC includes broad fixed-wing piston aircraft acceptance, testing continues for rotorcraft with Robinson deep into its program with the fuel. Cirrus Aircraft is also testing the fuel within its fleet.

But any fuel that makes it to market must also demonstrate commercial viability. It must make it from the manufacturer through the distribution channels—pipeline or trucking—to the airport where it goes into a tank, and then into our fuel tanks on aircraft. That means the fuel must be acceptable in each of those steps by the businesses involved, as well as the end user burning it in flight.

“With the GAMI fuel, the path that they chose to take is to do their proprietary STC approval, which is perfectly fine on the safety side with the FAA, but they also chose not to enter into an ASTM consensus specification process,” said Desrosier. “Typically that’s how all the other stakeholders in the community become familiar with a fuel…the content of the fuel, the understanding of the evaluation and the assessments of the fuel, and the understanding of the components, and the understanding of the business risks related to being a stakeholder who might purchase, who might produce, who might distribute, who might dispense, and who might put it into people’s tanks.

“There’s a lot of business decisions in this, and a lot of risk.”

Swift Fuels has already entered the market with a lower octane unleaded fuel, 94UL, with limited distribution now but a growing foothold, especially in states and at airports where there is more pressure to get away from leaded avgas.

Swift is pursuing both an STC and ASTM path with its high octane fuel, 100UL, and it has chosen a clever way to gain market acceptance—and perhaps reach commercial viability—with the new fuel. For its current 94UL, Swift offers a “Forever STC,” through which an operator purchasing the STC for the lower octane fuel is promised that the STC for the 100UL fuel will be  included in that purchase when it’s available.

Swift will be able to deliver the fuel through the existing infrastructure to the existing tanks it has put in place for 94UL. According to Desrosier, Swift has already started the consensus standard and is going through the STC process. Critically, the manufacturer will share the results through the consensus process, and when it obtains FAA approval, it will share that data with all the stakeholders.

Two other fuels are pursuing approval through the PAFI (Piston Aviation Fuels Initiative) program. One already has the ASTM test specification, produced by Afton Chemical/Phillips 66, and it is continuing to share information, according to Desrosier. It has to go through the full ASTM testing process, but it has “the roadmap” to do it.

The other candidate fuel (Lyondell/VP Racing) is close behind. The consortium has entered into the specification process and expects to also share its progress.

One big question in my mind: Will we end up with more than one fuel, and will they be intermixable? I asked Desroiser, along with the follow-up question: Is this testing pathway defined or is it wait and see?

No, said Desrosier, the fuels are not allowed to intermix and co-mingle. All of the candidate producers are testing to comingle with 100LL—because that is part of the transition process and very likely to occur in the field.

“In terms of ‘could be,’ it depends on the final composition of the fuels,” he said. “We do know some of the key components,” and some fuels will not be able to mix because they are too different.

In the end, having two fuels make it through the process means that the market will decide—and we will have a backup in case of an unforeseen issue with a producer or fuel. “We think it’s going to have to be a market decision,” said Desrosier. “I’m not expecting a significant market penetration, dividing the market in half” with different fuels regionally available.

“Once you have the acceptance by FAA, ultimately the consumer is the very last in the supply chain,” he concluded. 

With the pilot or owner-operator, it often boils down to price—and that won’t likely change with 100UL.