Unleaded Fuels Testing Temporarily Suspended, Next Steps Being Developed

July 22, 2018 - The Piston Aviation Fuels Initiative (PAFI) is currently considering next steps for the development of unleaded fuels for the GA aircraft fleet after the FAA announced in June that it was temporarily suspending testing of the two fuels in the program, giving the fuel developers an opportunity to address some of the findings from the exhaustive testing.

Those two fuels, from Shell and Swift, have been studied since 2016 and were the final candidates of 19 fuels to advance to full-scale engine and flight testing.

PAFI was developed as a collaborative program between the FAA and the aviation and petroleum industries to find a satisfactory high-octane unleaded replacement for 100LL avgas, which is currently used by the vast majority of piston aircraft in the U.S. GA fleet.

Full-scale engine and aircraft testing has been temporarily suspended to allow time for fuel developers to assess and potentially address differences between the unleaded fuels and 100LL. As satisfactory mitigations to these differences are developed PAFI will continue to evaluate the fuels further.

In the meantime, PAFI, through the FAA, has also reached out to other fuel developers with proposed fuels that emerged after the program was established, or who had previously declined to participate in the initial competitive process, to determine if further examination of any of those fuels is warranted.

“The collaborative FAA-industry PAFI program has done exactly what it was designed to do — take promising fuels and subject them to rigorous, standardized materials, engine, fuel system, and aircraft testing, developed and agreed to by the full breadth of industry, to determine their performance characteristics and any limitations they might pose in satisfying the general aviation fleet,” said Doug Macnair, EAA’s vice president of government relations. Macnair has been EAA’s representative to the PAFI program from its inception.

He said finding a fuel that safely and cost-effectively meets the requirements of the GA fleet, and has the confidence of aircraft owners as well as engine and airframe manufacturers, is PAFI’s priority, and it does not intend to introduce fuels to the market that do not meet these goals.

“What this process tells us is what EAA has maintained for the past 30 years: Finding a high-octane unleaded avgas replacement is a daunting technological challenge,” Macnair said. “EAA joins everyone in the industry in welcoming all potential solutions to take part in this standardized and industry-accepted testing protocol, so together we can find the best and broadest possible solution for the GA fleet.”

Representatives from Shell (Booth 450 in the Main Aircraft Display) and Swift Fuels (Booth 461 in the Main Aircraft Display) are exhibiting at AirVenture and available to answer questions about their proposed fuels.

The PAFI program’s efforts to evaluate high-octane unleaded alternatives to 100LL will continue into the future and will include facilitating the eventual deployment of any future fuel.

Full commercialization and deployment of a replacement for 100LL will only occur through the collaboration of the aviation and petroleum industries, along with environmental and aviation regulators. Macnair said the strength of the PAFI program is in bringing all of the necessary resources and knowledge together to work toward a common understanding and potential solutions.