Approaches to busy airports are often noisier and less fuel-efficient than they technically could be. This is because aircraft have to be configured in an individual process before touchdown. Pilots reduce speed, set flaps, extend slats and finally deploy the landing gear. However, air traffic control restricts the flight profile, and pilots often have limited information about weather conditions. Thus, the practical configuration sequence and the noise and fuel consumption of an approach depend very much on the decisions made by pilots and their access to important information such as the current wind conditions. With the development of the Low Noise Augmentation System (LNAS), the German Aerospace Center (Deutsches Zentrum für Luft und Raumfahrt; DLR) hasalready shown how pilots can be effectively supported for noise- and fuel-consumption-optimised approaches. The European 'Dynamic Configuration Adjustment in the TMA [Terminal Manoeuvring Area]' (DYNCAT) project is now analysing the interaction between aircraft and air traffic control during the approach phase. When the project is completed at the end of 2022, the researchers aim to have developed suggestions for improvements to operations both on board aircraft and on the ground, in order to enable a whole-system solution for quieter and lower-emission approaches.
"We want to find out where regulatory changes in air traffic management can make approaches more efficient," explains DYNCAT Project Manager Fethi Abdelmoula from the DLR Institute of Flight Systems. "We are also looking at how pilots can be better supported under existing air traffic control requirements and prevailing weather conditions." At a kick-off seminar for the project in March 2021, a broad international group of participants consisting of air traffic controllers, pilots and experts from various air transport authorities including the US Federal Aviation Administration (FAA), the European Organisation for the Safety of Air Navigation (EUROCONTROL) and the German Air Traffic Control Service (Deutsche Flugsicherung; DFS), discussed this subject with researchers. "Here, it was already apparent from the first exchange that pilots would like additional information and more communication with air traffic control," Abdelmoula continues. The project work is also based on extensive measurement data acquired during 640 approaches to Zurich Airport. These are being comprehensively evaluated in order to more precisely identify the potential for reducing noise and emissions with optimised approaches.
A landing approach begins when an aircraft leaves its cruising altitude some distance before the destination airport. By the time it has descended to an altitude of 1000 feet, at approximately 5.5 kilometres (three nautical miles) from the touchdown point, the aircraft must be in full landing configuration with the slats, flaps and landing gear extended. Up until this point, there are large variations in speed, altitude and the timing of deployments of high-lift devices and landing gear along the flight path. This in turn leads to different distances and timings for the approach phase, but also to varying fuel requirements and noise emissions as perceived on the ground. The goal is to make these sequences more predictable and thus easier to plan for the pilots and to support them in implementing them efficiently.