The FAA’s Piston Aviation Fuels Initiative (PAFI) will resume testing a possible unleaded replacement for avgas this fall, according to AOPA. The FAA suspended most PAFI testing operations in June to assess issues related to the differences between 100LL and the two unleaded test fuels—one developed by Shell and one by Swift Fuels. That announcement was followed by Swift Fuels halting its work with the program in late August to pursue development and certification of an unleaded avgas replacement outside of PAFI.
The PAFI Steering Group made the decision to resume testing on the Shell fuel at its quarterly meeting, which was held at AOPA Headquarters in Frederick, Maryland, at the end of August. Peter White, the FAA’s alternative fuels program leader, said in an interview with AOPA that the break in testing has provided time for development of mitigations for the problems encountered. White also said that the FAA has been working with the Environmental Protection Agency (EPA) regarding future regulation of leaded avgas.
Originally scheduled to wrap up in December 2018, the end date for PAFI testing has been pushed to late 2019. The FAA has said that it is also interested in seeing data on unleaded fuels developed outside of PAFI.