The US Federal Aviation Administration (FAA) has selected two fuels for further testing in the search for unleaded avgas, the regulator announced this week.
Under pressure from environmental lobbyists to ban 100LL and other leaded avgas types, the FAA has been working with fuel companies to find an acceptable "drop-in" replacement that the existing piston GA fleet can run on.
Of the six companies who submitted samples to the FAA under the Piston Aircraft Fuels Initiative (PAFI) program, only four were chosen for Phase 1 testing, and now only formulations from Shell and Swift Fuels will go on to Phase 2 engine and aircraft testing.
Test data will help the companies obtain an ASTM International Production Specification for their fuels and allow the FAA to authorize the existing GA fleet to use the unleaded replacement fuels. The testing will begin this year and finish in 2018.
PAFI is a joint government-industry partnership partly funded by the US Congress with a budget of US$7 million for the 2016 fiscal year.
“Government and industry are successfully working together to lower aviation emissions," said FAA Administrator Michael Huerta. "We’re on track to have unleaded aviation gasoline fully evaluated and ready to be authorized for use by the general aviation fleet in 2018.”
If the FAA is successful in approving an unleaded avgas for use in the USA, the Australian market for 100LL is likely to be too small to justify continued production, forcing a change to the new fuel over here as well.