Assessing vertical flight profiles in the US and Europe

Abstract

Air traffic management analysis efforts today are focusing more on trajectory-based operations as a basis for better air traffic control and modernization. Developing proper indicators that correctly characterize these operations has been a key activity for both EUROCONTROL and the FAA. Both organizations are working jointly towards harmonizing the generation of existing metrics to allow for a more analogous comparison between ATM in Europe and in the USA. Harmonization efforts have been challenging due to numerous factors, e.g. missing data or processes that cannot be easily changed due to various system dependencies. One such topic under consideration is vertical flight efficiency, which measures the amount of level flight occurring after the top of descent until an aircraft reaches its destination airport. Various causes of level flight include weather conditions, airport capacity, airspace design and restrictions, and air traffic flow control. A higher level flight value (in terms of the number of level-offs, the total time flown level, or the total level distance) is an indicator of reduced vertical flight efficiency, since a gradual, consistent descent without level-offs from the TOD to the runway is seen as ideal. Benefits of a continuous descent operation or optimized profile descent include better fuel economy, reduced noise, and less pollution. The results of this study show that flights into European airports undergo less level flight on average than flights into US airports: the average level distance per flight is 15.3 NM in Europe and 28.7 NM in the US. Nevertheless, the potential fuel savings are similar: on average 43.5 kg and 43.9 kg of fuel per flight in the US and Europe, respectively. The results of this study are promoted for wider usage by the international ATM performance benchmarking community.