Green Flight International has completed the first U.S. cross-country flight with a jet-powered aircraft fuelled predominantly with biofuel. The flights used a first-generation biodiesel, and the team is now planning flights using algae-based bio-jet fuel.

The Aero L-29 jet trainer was flown 2,486 miles from Reno, Nevada, to Leesburg, Fla. Of that distance, 1,776 miles were flown on 100% biofuel and 710 miles on a blend of 50% biofuel and 50% standard jet fuel.

Virgin Atlantic Airways in February flew a Boeing 747-400 from London to Amsterdam with one of its General Electric CF6-80C2 turbofans burning a blend of 20% biofuel and 80% conventional jet fuel.

"These flights prove that we have the capability of supplementing our energy requirements with safe, environmentally friendly alternatives to petroleum," says Green Flight President and CEO Douglas Rodante.

The cross-country flight followed more than a year of ground and flight testing of the Soviet-era trainer's Walter M701 turbojet with biofuels from different feedstocks. Supplied by Lake Erie Biofuels, the biodiesel chosen was a blend of 75% soy and 25% animal fat, says Rodante. Lockheed Martin performed laboratory testing of the biofuel.

Because biodiesel has lower energy content than kerosene, the FAA required the L-29 to land with a 25% fuel reserve. This limited each leg of the cross-country flight to less than 300 miles. But Rodante says range on biodiesel was "not much less" than with jet fuel.

To avoid any cold-flow issues with the biodiesel, the legs were flown at 13,000 to 17,000 feet to ensure the fuel would not freeze, he says. Extensive ground tests preceding the flight had not revealed any issues with filters or seals.

A blend of biodiesel and kerosene was used on three legs of the flight to compare performance and demonstrate the ability to blend biofuel and existing jet fuel. "No one is going to run 100% with first-generation biofuel," he says.

"Our original idea was to demonstrate supplementation of jet fuel with biofuel," Rodante says. Data is still being analyzed, but he believes there was negligible performance impact with the 50:50 blended fuel.

Orlando-based Green Flight, formed and funded by Rodante to promote use of biofuels, is now planning flights early in 2009 using a next-generation, sustainable algae-based bio-jet fuel. "We are negotiating with a fuel supplier and plan further tests," he says.

Air New Zealand, Continental Airlines and Japan Airlines all plan demonstration flights over the next few months using second-generation bio-jet fuels derived from feedstocks such as jatropha that do not compete with food for land or water.

Photo: Green Flight International