The concept of “first come, first served” – applied by the air traffic control in the past – had the drawback of queuing aircraft at the arrival route entries just before the end of the night flying restrictions, causing unnecessary noise and CO2 emissions. In the framework of the iStream project at Zurich Airport, skyguide, together with other air navigation service providers, airlines, airports and regulators has undertaken trials concerning early morning flights into Zurich. With the introduction of Target Time Management, a precise slot is assigned to each aircraft, thus increasing the fluidity of air traffic and reducing noise as well as fuel consumption.
In the same vein, the extended arrival management, also known as XMAN, is optimising the arrival flow and cutting the aircraft’s holding time at airports by adapting their cruising speed while still in the airspace of adjacent control centres, often several hundred kilometres away from the airport, which reduces fuel burn and CO2 emissions. Less airborne congestion in terminal areas will also contribute to improving operational safety by reducing the workload of pilots and air traffic controllers and limiting noise.
« Our technical systems, airspace design and operational procedures are continuously improved to offer increased safety and capacity to airspace users. This in turn usually helps to shorten flight trajectories, thus saving fuel and lowering CO2 emissions. » – Thierry Brégou, Environmental Affairs
Additionally, the improvement of procedures makes it possible to improve flight trajectories in the vertical plan. International letters of agreement for the summer and winter seasons have been signed concerning the handover of responsibilities between the controllers of different centres. This helps to optimally adjust flight profiles according to the differences between low- and high-traffic periods, governed by the principle that the energy efficiency of an aircraft varies with its cruising altitude. Thus, 7.8 GWh per year can be saved in keeping aircraft at their optimum flight level as long as possible.
Finally, major savings will stem from the gradual introduction of more direct routes. Improvements are implemented every year within the framework of the Direct Routing Airspace project. This enables better planning of flights passing over Switzerland, with shorter flight routings. An even more ambitious project – Free Route Airspace – is intended to be implemented by 2022.