The NASA Armstrong Flight Research Center Douglas DC-8 N817NA (c/n 46082) recently flew in Europe to study the climate impact of alternative fuels.
Operating from Ramstein Air Base it operated in controlled airspace over Mecklenburg-Vorpommern, Germany in conjunction with the German Aerospace Center (DLR) Airbus A320-232 Advanced Technology Research Aircraft D-ATRA (msn 659).
The A320 flew with a blend of biofuel and conventional Jet A-1 under contrail-forming and noncontrail- forming conditions. The DC-8 flew along a straight path a few miles behind equipped with 14 measuring instruments that sniffed the exhaust streams left by the A320. The emissions and the resulting contrails and contrail cirrus clouds were measured at different altitudes and flight speeds. Each flight lasted four to five hours and involved the aircraft undertaking 180o turns at the end of each path before heading on to another straight run. In addition, the A320’s exhaust gases were studied in static tests using ground-based measuring instruments and the DC-8 collected data relating to the properties of cirrus clouds during its flight to Germany from its NASA Armstrong base at Edwards AFB. The flights are intended to discover if the lower soot emissions produced by alternative fuels impact on the ice particles in contrails, and if a blend of 30% biofuel and 70% Jet A-1 generates a similarly low level of soot emissions to a 50/50 biofuel/Jet A-1 blend. Patrick Le Clercq of the DLR Institute of Combustion Technology said a 30% biofuel/70% Jet A-1 blend would be, “markedly more economical” than a 50/50 blend and therefore potentially more coste effective in commercialising biofuels for civil aviation. Mark Broadbent