All unleaded fuels in both STC type certification and PAFI programs have performed well across all the engines tested, showing positive results such as reduced engine wear and cleaner operation, particularly in Continental engines. It is not practical nor possible to conduct testing on each make and model of piston-engine across the entire U.S. aircraft fleet. Therefore, FAA certification and authorization testing uses an “envelope” approach to ensure safety and compatibility across a wide range of engines. by identifying key performance and design characteristics that impact safe operation and specific engine which represent the corners of the envelope.

Based on a specific unleaded fuel performance and composition, the primary focus areas for testing to ensure safety of the fleet are detonation, materials compatibility, and engine durability.

• Fleet Authorization Pathway – Information about the PAFI test program, including specific engines identified for testing of detonation, performance and durability, as well as the current status of testing is available from the EAGLE website: www.flyeagle.org
• STC Pathway – The FAA type certification process is conducted between an applicant and FAA; all project details are proprietary, so please contact those companies for any additional information such as testing of specific make and model engines.