Off-Idle Continuous Descent Operations at Schiphol Airport

Abstract

The Compound Annual Growth Rate (CAGR) of the aviation industry is predicted to be 4.1% from 2015 to 2045 [23].In recent years, however, increasing public pressure has been put on the industry to further reduce noise and carbonemissions. This can be done by eliminating all horizontal flight segments during the approach phase, reducing theaverage thrust. Such an approach is called a Continuous Descent Approach (CDA) and has been the subject of manystudies. Ideal CDAs are flown with idle thrust, which results in the largest fuel flow reduction but which has a verybig drawback; The vertical profiles of ideal CDAs vary greatly between aircraft making it difficult for ground-basedsystems to predict the exact position of an aircraft ahead of time ([35]). In order to deal with this added uncertainty,additional separation is needed. This greatly reduces the capacity, which means that such a concept can only beused when there is little traffic. ([26]) This greatly limits the benefits since there is very gain during such times. Thereare other types of CDAs, which take away the need for this added uncertainty, however. These are called a fixed orconstant Flight Path Angle (FPA) approaches. Where the FPA during ideal CDAs is optimised by each aircraft’s FlightManagement System (FMS) for that particular flight, an average is used for this type. This average is then flown witha small, off-idle, amount of thrust. Which means that although in general the noise and emission reductions aredecreased when compared to ideal CDAs, ([35], [8]) the capacity is increased ([25]).In this thesis, fixed-route fixed FPA approach procedureswill be designed for the SchipholTMA and compared to currentdesigns. This will be done by trading off the environmental benefits for capacity under robustness and flexibilityconstraints. Although only part of the descent occurs inside of the TMA, most of the emission and noise reductionscan be achieved here as the inefficient level segments that usually occur here are moved to the upper airspace ([32]).