A German flying club has begun using renewable diesel fuel made from waste cooking oils and other plant materials in three Cessna 172 aircraft at Hamburg Airport. The Hanseatic Flying Club introduced the alternative fuel on Monday, Nov. 2, following technical evaluations and manufacturer approvals, according to German radio and television broadcaster NDR.
Fuel Approved for Diesel Engines
The fuel, marketed as Cair XTL, is a hydrotreated vegetable oil (HVO) product manufactured using used cooking oils, plant residues and hydrogen. The club’s aircraft are equipped with Continental diesel engines rather than conventional, gasoline-powered piston engines. Continental approved the fuel following technical testing, and the club also obtained authorization from the aircraft manufacturer.
According to German press agency dpa, the club estimates that its diesel-powered aircraft consume approximately 20 liters (5.3 gallons) of fuel per hour. Hamburg Airport is providing a dedicated fueling truck to support the operation.
“Alternative aviation fuels are being advanced on many fronts,” club board member Enrico Hemling said in comments published by NDR, translated from German. “As a volunteer-run training organization, we want to actively support this development and show that alternative fuels can already be used in practical flight operations today.”
Airport Expands Existing Fuel Program
Hamburg Airport has used HVO in its ground vehicle fleet, including airport firefighting equipment and ground handling vehicles, since 2016. The airport estimates that the program has reduced carbon dioxide emissions by approximately 15,000 metric tons over the past decade.
The development comes as alternative aviation fuels receive increasing attention internationally, including the FAA’s unleaded avgas transition in the United States, although HVO is a diesel fuel and cannot directly replace 100LL in conventional gasoline-powered aircraft.
There’s a significant learning curve here. As there was with bio diesel fuel in trucks. Injectors and pumps need to be modified, as well as other components, to run effectively. This certainly isn’t a plug and play task. It’s one thing to have a truck quit from fueling issues. Quite another for an aircraft…