Adherence to best descent profiles An analysis of the relative vertical (in)efficiency at four major European airports

摘要

This paper presents an assessment of the vertical efficiency in descent at four major European airports using best local practice for each flow as a reference. The motivation is to assess the potential for short term improvements through an increased adherence to these best practices. The assessment relies on the analysis of the vertical deviation to best descent profiles of each airport, in relation to the additional flight time as a proxy for the level of congestion. It focusses on the 50NM area around each airport and relies on six months of data from 2018 during day-time operations over more than 200 000 flights in total. The assessment reveals a triple relative inefficiency. Firstly, descent profiles significantly lower than best practices: the median vertical deviation for 10 minutes flight time exceeds 2300ft. Secondly, a degradation of descent profiles with the level of congestion: the median vertical deviation for 10 minutes flight time increases by 800ft per 1 minute additional time. Thirdly, a variability of descent profiles for a same level of congestion: the vertical deviation span (90% containment) for 10 minutes flight time is 2000ft or more for a same additional time. The detailed analysis per runway and per flow of the two airports having the highest vertical deviation reveals that while one shows consistent performances, the other one shows more variabilities. Further work should involve the identification of the causes of large vertical deviations and possible ways to reinforce adherence to best descent profiles.