Alternative fuel sources are becoming an operational reality; these fuels have the potential to reduce emissions, improve combustion characteristics and to increase fuel supply security. A test with a T56 turboprop engine was performed to demonstrate that a CHEFA/JP8 (Camelina Hydroprocessed Ester and Fatty Acids and standard JP8) fuel blend would meet operational requirements. The primary test objective was to assess whether a fuel change had an immediate impact on the engine condition, performance, emissions or vibration characteristics. This paper presents test results comparing engine performance with JP8 and a 50/50 blend of JP8 and CHEFA. Comparison runs were conducted before and after a 20 hour ground durability test with the CHEFA fuel blend. A nearly time-expired, nacelle-dressed T56 on an outdoor test stand was tested. The engine was equipped with minimally-intrusive non-standard pressure, temperature and emissions monitoring equipment, and a field vibration assessment suite in addition to the standard flight instrumentation. This paper discusses the test plan, data acquisition methods, results and data repeatability. The performance and emissions results are compared to the changes predicted theoretically from the fuel properties. Observations from the borescope inspections before, during and after the 20 hour durability test are also presented. The lessons learned in this test could be applied to future fuel or process-change tests, and the results provide a performance baseline for engine health assessment.

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