100LL Replacement on the Way

July 25, 2016 - Are reports of the impending demise of 100LL true, and if so, where is your next tank of avgas coming from? An industry government partnership that’s been working on developing a high-octane alternative aviation fuel has reached an important milestone, and today leaders of the Piston Aviation Fuels Initiative (PAFI) will provide a comprehensive update on the program at 11:30 a.m. on Tuesday July 26 at Forum Stage 10.

The EAA has been one of the lead organizations involved in PAFI — which commenced at EAA AirVenture Oshkosh  2010 — along with AOPA, GAMA, the FAA, and others. After a preliminary round of testing candidate replacement fuels, four were approved for more rigorous Phase 1 testing, and those tests have recently concluded.

“It was incredibly exhaustive testing,” said Doug Macnair, EAA vice president of government relations, noting that high octane is just one of many properties a 100LL replacement fuel must meet. Flash point, density, cold and hot start ability, compatibility with existing high-performance aircraft engines and components, storage stability, and compatibility with the existing distribution infrastructure are among the other performance benchmarks that must be met. An independent body of technical experts has evaluated the results of the Phase 1 tests and selected two fuels — Shell Oil’s Shell UL100 and Swift Fuel’s Swift UL102 — for the final, Phase 2 tests. These two fuels will now undergo more exhaustive full-scale testing, first in engines and then in operational aircraft.

“... aircraft and engines were carefully chosen to represent the entire universe of general aviation (piston-powered) aircraft, without testing the whole fleet,” said Macnair. “We’re now beginning to deliver fuels to test facilities.”

Phase 2 testing will be completed by the end of 2018, at which point one or both of the fuels are expected to receive fleetwide authorization from the FAA, approving their use in all piston-powered GA aircraft.

Avgas is the only remaining leaded fuel used in the United States, and the Environmental Protection Agency has held off efforts to impose regulations on 100LL emissions in anticipation of the successful outcome of the PAFI program. In addition to health and regulatory concerns about the leaded fuel, only one company in the world makes the leaded additive that gives avgas its high octane boost, and given the relatively small market, there’s no guarantee the company will continue producing the additive, adding to the impetus for finding an unleaded alternative.

PAFI participants acknowledge that as far as the program has come, many challenges are ahead, and at today’s forum attendees can tank up on the latest news from this vital program. Joining Macnair on the forum stage will be David Oord, AOPA’s senior director of government affairs, regulatory; Walter Desrosier, GAMA’s vice president of engineering and maintenance; and Peter White, FAA manager, alternative fuels program staff, AIR-20.