Ground-based aircraft exhaust measurements of a Lufthansa Airbus A340 using FTIR emission spectrometry

The emission inventories of aircraft emissions are being set up using flight routing data and test rig measurements of the engine manufacturers for certification purposes which have to be extrapolated with respect to the actual parameters at cruise altitude. Precise data from in-service engines are not existing. FTIR-emission-spectroscopy as a remote sensing multi-component exhaust gas analysis method has been further developed to specify the traceable molecules in aircraft exhausts, to determine the detection limits, and to obtain reliable statements concerning its accuracy. The first measurement with the Airbus A340 engine CFM56-5C2 during run up tests at ground level showed the overall ability of the FTIR-emission system to analyze the exhausts of modern gas turbines with high bypass ratio and mixing of fan air into the exhausts before the nozzle exit. Good quality spectra were measured and analyzed with respect to the mixing rations of CO 2 , H 2 O, CO, NO, and N 2 O, and the emission indices of CO, NO, and N 2 O. Total measurement times at one thrust level should be about 15 minutes to obtain reliable result which can be compared to the ICAO data of this engine.