The Alternative Fuel Effects on Contrails and Cruise Emissions (ACCESS) experiment involved flying a NASA Dryden Flight Research Center DC-8 airplane as high as 39,000 feet while an instrumented HU-25C Guardian aircraft, based at NASA’s Langley Research Center, trailed behind at distances ranging from 300 feet to more than 10 miles. The team measured exhaust composition and contrail characteristics depending on fuel type, plume duration and atmospheric conditions.
During the flights, the DC-8’s four CFM56 engines were powered by conventional JP-8 jet fuel, or a 50-50 blend of JP-8 and an alternative fuel of hydroprocessed esters and fatty acids produced from camelina plant oil. More than a dozen instruments mounted on the Guardian jet characterized the soot, gases and ice particles streaming from the DC-8.
Bruce Anderson, a senior research scientist at Langley who worked on the project, tells the Associated Press that these fuels are “quite acceptable” for use in commercial jets.
The latest test flights follow a pair of alternative aviation fuel experiment studies conducted in 2009 and 2011. Ground-based instruments measured the DC-8’s exhaust emissions as the aircraft burned alternative fuels while parked on a ramp in California.
A second phase of ACCESS flights is planned for 2014. It will build upon learned from this year’s flights and include a more extensive set of measurements, NASA says.
The ACCESS study is a joint project involving researchers at Dryden, NASA’s Glenn Research Center in Cleveland and NASA Langley.
Last month, the USDA extended for five years its agreement to work with the FAA and commercial aviation partners, including Boeing and industry trade group Airlines for America, to help develop a viable biofuel for the aviation industry.