Access II confirms jet biofuel burns cleaner

Flying high above the California desert, NASA researchers recently took to the skies for the second year in a row with a DC-8 and other aircraft to study the effects on emissions and contrail formation of burning alternative fuels in jet engines.

This follow-up set of Alternative Fuel Effects on Contrails and Cruise Emissions flight tests, known as ACCESS II, repeated a similar series of tests flown during 2013, while also adding a few new wrinkles to the investigations to capture more and better data. Within NASA, ACCESS II was a joint project involving researchers at the Armstrong, Langley, and Glenn research centers. The research supports NASA aeronautics’ strategic vision, which has as a goal to enable transition of industry to low-carbon fuels and alternative propulsion systems.

ACCESS II involved flying NASA’s workhorse DC-8 (photo) as high as 40,000 feet while its four CFM56 engines burned either JP-8 jet fuel, or a 50-50 blend of JP-8 and renewable alternative fuel of hydro processed esters and fatty acids produced from camelina plant oil.

A quick look at the ACCESS II data confirmed with high certainty the results from ACCESS I, which showed at least a 50 percent reduction in soot emissions from the DC-8 when it burns the blended fuel as opposed to the jet fuel alone.

It is hoped the research will help lead to more environmentally friendly aircraft designs and worldwide flight operations, especially in light of the explosive growth in global air travel that is forecast for the decades ahead.