GAMI Gets STC for Unleaded AvGas for Popular Lycoming Engines

The O-360 horizontally-opposed engine powers a wide range of light GA aircraft. Courtesy Lycoming

General Aviation Modifications, Inc., (GAMI) has announced the STC for its G100UL avgas for Lycoming O-320, O-360, and IO-360 engines. The move came with broad support and cheering from those in the industry who have been working hard towards solving the problem of leaded fuels in piston-powered aircraft.

The STC comes after years spent by GAMI in the research and development of an unleaded avgas solution. This initial result is the proprietary, high-octane G100UL fuel, optimized for the series of normally aspirated, 4-cylinder engines that power a significant portion of the light GA fleet. It’s a step towards the big goal of a replacement fuel for 100LL that will incur no loss in safety and performance for those aircraft and can be delivered reasonably within the GA community.

A trio of GA associations applauded the announcement and what it means for the fleet’s ability to transition to a more sustainable operating environment. “We commend GAMI for its hard work and commitment to producing a high-octane unleaded avgas and support its continued testing on a broader range of engines and airframes,” said GAMA’s president and CEO Pete Bunce. “While this STC is a start, demonstrating the safety and viability of a high-octane fuel as a replacement for 100LL requires significant testing on high performance engines, as well as certain airplanes and helicopters at the most demanding boundary of the performance envelope encompassing the existing fleet of aircraft.”

“We appreciate GAMI’s long-standing commitment to addressing the immense technical challenges of replacing leaded high-octane avgas with an unleaded solution intended to satisfy the safety and performance needs of the fleet,” said EAA’s president and CEO Jack Pelton. “This STC is a positive first step and we look forward to GAMI’s continued efforts to add additional engines and ideally working toward a path for fleet-wide authorization.”

“This STC is a positive step as we seek a fleet-wide solution for an FAA approved unleaded fuel,” said AOPA’s president and CEO Mark Baker. “We look forward to learning more about how the STC will be used, and next steps in expanding the number of engines that can safely take advantage of it.”

The associations have worked together in partnership with the FAA under the umbrella of the Piston Aircraft Fuels Initiative (PAFI), which was formed to evaluate and test various potential replacement fuels for 100LL. Several fuels by other manufacturers are also under consideration.

Based in Maryland, Julie is an editor, aviation educator, and author. She holds an airline transport pilot certificate with Douglas DC-3 and CE510 (Citation Mustang) type ratings. She's a CFI/CFII since 1993, specializing in advanced aircraft and flight instructor development. Follow Julie on Twitter @julieinthesky.

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