Calculation of NOx Emissions of Short and Medium-haul Domestic Flights with Consideration of the Ambient Effect

Abstract

In this study, NOx emissions of typical flights at two domestic round trip routes (206-271 NM and 625-740NM) are quantified. The flight and engine parameters were obtained from actual flight data records, whereas the emission index of sea level NOx was obtained from the emission database of the International Civil Aviation Organization for a specific type of engine. Using the Boeing Fuel Flow Method 2 for altitude correction, the total flight NOx emissions are found to be on average 66.2 kg for short and 152.2 kg for medium flight distance, showing a NOx per kilometer of between 0.32 and 0.21 g/km. The fraction of landing and takeoff NOx emissions changes between 17.2% and 10.0% on average, depending on flight distance. The average total flight NOx emission per kg fuel burned is calculated to be 31-32 g/kg fuel. When a constant relative humidity is assumed as 60% during an entire flight, the total NOx emissions is found to be up to 12.1 kg lower than for those where the relative humidity depends on altitude.