A Diesel Conundrum

Peter Mauer, CEO of Diamond Aircraft (which uses Thielert (TAE) diesel engines), responds that the technical concerns expressed specifically by fuel supplier ExxonMobil are, “valid general concerns for operation of diesel engine powered aircraft. In the case of TAE and Diamond, all listed reasons, specifically ignition quality, freezing point, and lubricity, have been addressed as part of the engine and aircraft certification process and approved by the responsible airworthiness authorities.”

The FAA says: “It is anticipated that CI engines will use jet fuels, such as Jet-A, which are produced in accordance with the ASTM International Specification D1655, or automotive diesel fuels produced in accordance with automotive fuel specifications.”

ExxonMobil’s bottom line, as of November, is: “No fueling of diesel engine aircraft with Jet Fuel may be performed without a valid indemnity agreement signed by the customer in place.”
So the debate continues. As the aviation industry shifts to more efficient and more “green” power plant and fuel alternatives in the coming years, debates like these will become more and more prevalent. They are necessary since the voicing of differing viewpoints is an effective way to ensure that we eventually end up with safer, more cost effective, environmentally friendly power plants and aircraft.

Scott Fisher is an A&P and received his training at Dakota Aero Tech in Fargo, ND.