Finding the climate optimal cruise altitude for a selection of aircraft types and mission combinations

The climate impact of aviation is assessed as function of the emission altitude for two different aircraft types, the Boeing 787-800 and Boeing 777-300ER. The basis for this research is an assembly of 2,738 historical trajectories for which the fuel consumption and emissions were determined by using Piano-X aircraft performance data and atmospheric weather data from the European Centre for Medium-Range Weather Forecasts. The resulting emissions served as input for the climate response model AirClim which calculated the resulting climate response over time. To analyze the effect of changes in cruise altitude, the fuel consumption and corresponding emissions were recalculated for scenarios with relocated cruise altitude profiles ranging from an upward shift of 2000 ft to a downward shift of 18000 ft with respect to the original cruise altitude. By shifting cruise altitudes down, the total climate impact was found to be reduced for both aircraft types where the minimal climate impact is found for the lowest analyzed cruise altitude. The reduction in climate impact is mainly the result of the reduced short term forcings from contrail cirrus, ozone and the induced destruction of methane where their individual contribution to the total climate impact reduction was found to be dependent on aircraft type. Relocating cruise altitudes up was found to increase the climate impact for both aircraft types.Aerospace Engineerin