On Friday, one day after the FAA issued a draft policy statement on authorizing use of unleaded avgas for all piston-engine airplanes and helicopters, the Environmental Protection Agency (EPA) published a “proposed determination” that lead emissions from these aircraft using 100LL “cause or contribute to lead air pollution which may reasonably be anticipated to endanger public health and welfare.”
After considering comments on the proposal, the EPA plans to issue any final endangerment finding in 2023. If the EPA makes such a determination, the agency would subsequently propose regulatory standards for lead emissions from aircraft engines.
Said EPA: “Such a final determination would also trigger the FAA’s statutory mandate to prescribe standards for the composition or chemical or physical properties of an aircraft fuel or fuel additive to control or eliminate aircraft lead emissions.”
In September, the FAA granted supplemental type certificates (STC) for the use of Ada, Oklahoma-based General Aviation Modifications Inc. (GAMI) G100UL high-octane unleaded fuel in the piston-powered aircraft fleet. Draft FAA document PS–AIR–20–2000 provides the process for approving the piston aircraft fleet as a whole in lieu of obtaining individual aircraft model STCs. The FAA will continue to support applicants seeking approvals that would allow the use of unleaded fuel formulations via the traditional STC and amended TC process.
Comments on draft PS–AIR–20–2000 are due by December 5.