To get to this stage, Shell Aviation technologists carried out an intensive internal laboratory program, including in-house altitude rig and engine testing. Working alliances were then formed with aviation engine manufacturer Lycoming Engines (Lycoming) and the light aircraft manufacturer Piper Aircraft Inc. (Piper). As a result, the formulation was successfully evaluated in industry laboratory engine (bench) tests by Lycoming and in a flight test by Piper. 

“Lycoming Engines commends Shell on launching its unleaded Avgas initiative”, states Michael Kraft, Senior Vice-President and General Manager of Lycoming Engines. “They engaged Lycoming to test their fuel on our highest octane demand engine and we can confirm that it’s remarkably close to Avgas100LL from a performance perspective. This initiative is a major step in the right direction for general aviation.” 

“Piper Aircraft is pleased to participate with Shell and Lycoming in this feasibility flight test program,” said Piper Vice-President of Engineering Jack Mill. “Recently, we successfully flew an experimental non-production Piper Saratoga with Shell’s new formulation for about an hour. We appreciate the opportunity to work with Shell and Lycoming in this preliminary investigation of the technologies, which could in several years lead to flying unleaded fuel in our production airplanes.” 

Shell will now engage the aviation industry, regulators and authorities, including the US Federal Aviation Administration, American Society for Testing and Materials (ASTM) and European Aviation Safety Agency (EASA) to achieve approvals for the unleaded Avgas. Shell expects to also work with other OEMs to continue the testing and refinement program as the approvals process progresses.