The FAA will grant a fleet authorization allowing over two-thirds of the gasoline piston fleet to operate on 91UL avgas later this year.
The move is part of the FAA's efforts to eliminate lead from avgas. During a news conference, Lirio Liu, the head of certification for the FAA, announced that "approximately 68 percent of the general aviation fleet will be eligible to use UL91."
The development of an unleaded high-octane replacement for 100UL avgas is also underway per the original report on AVweb.
