Gaseous and Particulate Emissions Results of the NASA Alternative Aviation Fuel Experiment (AAFEX)


The Aircraft Alternative Fuels Emissions eXperiment (AAFEX) was conducted at National Aeronautic and Space Administration (NASA) Dryden Flight Research Center (DFRC) Aircraft Operations Facility (DAOF) in Palmdale, California, during January and February 2009. The purpose was to systematically investigate the effect of alternative fuels on both gas-phase and particle emissions from a CFM56-2C1 engine on NASA's DC-8 aircraft parked on the ground as functions of engine power, fuel composition, and exhaust plume age. Emissions parameters were measured at 6 engine power settings, ranging from idle to maximum thrust, in samples collected at 1, 30, and 145 meters (m) downstream of the exhaust plane as the aircraft burned three pure fuels and two fuel blends. The fuels included JP-8, two fuels produced using the Fischer-Tropsch process and 50/50 blends by volume of the F-T fuels with JP-8. The 1 m sampling rakes contained multiple gas and particle inlet probes and could also be traversed in order to measure the spatial variation of emissions across the engine exhaust plane. The #2 inboard engine on the left side always burned JP-8 while the #3 inboard right side engine was fueled with the various fuels and fuel blends. In addition, emissions from the Auxiliary Power Unit (APU) were also evaluated with both JP-8 and one pure F-T fuel. Both gaseous and particulate emissions are presented. Results show that the synthetic fuels reduced pollutant emissions while having relatively little effect on engine operation or performance.

Meeting Name

ASME Turbo Expo 2010: Power for Land, Sea, and Air (2010: Jun. 14-18, Glasgow, United Kingdom)



Second Department

Mechanical and Aerospace Engineering

Third Department



International Gas Turbine Institute

Keywords and Phrases

Aircraft Operations; Auxiliary Power Units; Aviation Fuel; California; Engine Exhaust; Engine Operations; Engine Power; Engine Power Settings; Exhaust Planes; Exhaust Plumes; Fischer-Tropsch Process; Flight Research; Fuel Blends; Fuel Compositions; Gasphase; Maximum Thrust; National Aeronautic And Space Administrations; Particle Emissions; Pollutant Emission; Spatial Variations; Aerodynamics; Carbon Monoxide; Coal Liquefaction; DC Power Transmission

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


File Type





© 2010 American Society of Mechanical Engineers (ASME), All rights reserved.

Publication Date

01 Jun 2010