CO2 emissions


Although international air transport is assessed at only 2 to 3% of the total emissions coming from human activities, ICAO has been asked to study how air navigation could contribute to the reduction of emissions.

Three means have been identified:

  • Technical progress: Despite an impressive technological development, progress in this field does not compensate for the effects of growth in the sector.
  • Economic measures: Among the economic measures considered to stimulate the reduction of emissions, the most promising one consists in the European Union emission trading scheme applied to air transport. Other measures such as the voluntary renewal of fleet through the introduction of more fuel saving aircraft contribute to a decrease in emissions.
  • Improvement of procedures: A better airspace management has been identified as a means of reduction of 6 to 12% of the en route emissions, in particular thanks to the use of more direct routes and to infrastructure improvement.

Several years ago, Belgocontrol and its partners introduced various measures in order to reduce CO2 emissions:

  • CDM (Collaborative Decision Making): At Brussels Airport, the implementation of CDM since 2001 limited emissions thanks to a better management of ground movements. CDM is a constant exchange of information that enables to reduce taxi times, to start the engines at the right time, and thus, to decrease fuel consumption of aircraft on the ground. Belgocontrol is one of the most advanced ANSPs in the field of CDM, thanks to the in-house developments of Airport Movement System (AMS). Moreover, in June 2010 Brussels National Airport became the second « CDM » airport in Europe after Munich. In comparing 2010 to 2000, i.e. before the gradual application of CDM, we register a gain in taxi time at Brussels National Airport of 7,931 hours. This corresponds to over 29,000 tons of CO2 and more than 33 tons of NOx.
  • CDO (Continuous Descent Operations): Since January 2009, Belgocontrol studies the application of CDO (Continuous Descent Operations) in collaboration with Eurocontrol, the airports and the airline companies. CDO is a flight technique where the aircraft descends without levelling off. The aircraft descends with minimal engine power, in function of the flight characteristics and the air traffic situation. As a result, less kerosene is consumed and the noise and greenhouse gas emission levels decrease.

    In September 2010 Belgocontrol launched the B3 project with Brussels Airlines and The Brussels Airport Company. The B3 project is supported by SESAR JU and studies the possibilities to increase the number of CDO (Continuous Descent Operations). The first phase of the project ran from September to December 2010 and consisted in gathering as much information as possible on the descent profiles of the aircraft in different circumstances with a view to optimize the current air traffic control procedures in order to authorize as many CDO as possible to pilots. During the second phase, the approach controllers continued to allow CDO within the restrictions imposed by safety and the collected data were analysed. The results and conclusions of the B3 project are presented in a final report issued on 3rd February 2012.

    The CDO procedure for Brussels National Airport was published in the AIP on 29 May 2014 and is of application since 26 June 2014 on runways 25L, 25R and 19. Not all landings can be performed using CDO; traffic conditions have to allow it.

    Benefits of CDO landings compared to conventional procedures :

    Aircraft type Fuel CO2emissions Noise (dB)
    A320 (narrow-body aircraft) -50 kg -157 kg -2 dB
    A330 (wide-body aircraft) -100 kg -314 kg -3 dB

  • FABEC (Functional Airspace Block Europe Central) : Belgocontrol participates in the construction of the Single European Sky and is a member of FABEC grouping 6 States – Germany, Belgium, France, Luxemburg, the Netherlands and Switzerland – and 7 air navigation service providers (those of the 6 States and MUAC). The Single European Sky has defined 4 key performance areas for the States and the air navigation service providers. Environment is one of them and the performance indicator in this area is the horizontal en-route efficiency of flights. The objective is indeed to decrease the flight duration by creating the most direct routes possible and by optimizing the network management so as to avoid obstacles on the flight paths, synonymous to delays, to waiting periods at the landing and therefore to more fuel consumption and greenhouse gas emissions.

    FABEC launched 2 optimisation projects of its current airspace (EIP, Early Implementation Packages) and 4 restructuration projects of its airspace. The 2 EIP, for which Belgocontrol lent its expertise, were implemented in 2010 :
    • The City Pairs project: aims to reduce the span of 50 of the least direct air routes between the major FABEC airports. According to the data collected in November 2010 for the 19 routes already modified at that moment, the annual economy amounts to 4,000 tons of fuel, which corresponds to over 12,000 tons of CO2.
    • The Night Network project: established a night route network enabling aircraft to take shortcuts by passing through military fly-zones that are not used at night. These new night routes are already being used in practice and are now made official and can be included in the flight plans. The benefits for the environment are comparable to those of City Pairs.

    4 FABEC airspace restructuration projects are currently in the pipeline : Project West, CBA Land/Central West, Project Lux and Project South-East. Their goal is to improve the route network to maximise the efficiency of the flights and therefore to reduce the impact of air traffic on the environment. The projects are expected to be implemented between 2012 and 2016.

    FABEC is also interested in ATFCM/ASM activities (Air Traffic Flow and Capacity Management/Airspace Management) that finalizes strategies to improve the procedures and co-ordinations, also with the military on a FABEC level.

    In 2010 FABEC created a new working group focussing its activities entirely on the environment: the Standing Committee Environment (SC ENV). Chaired by Belgocontrol, the SC ENV integrates an environmental management system in the operational FABEC projects and develops tools for evaluating environmental impacts. Jean-Claude Tintin, Belgocontrol CEO, is closely involved in the improvement of environmental performance, and is the Environment champion in the ANSP Strategic Board (ASB).

    More information about FABEC
  • Thanks to a better collaboration with our military colleagues we were able to introduce level 3 of the Flexible Use of Airspace (FUA 3+). This means that the military can put military airspace areas at the disposal of the civil traffic 3 hours in advance. By crossing these temporarily unused military areas, aircraft take shortcuts, decrease their flight duration and therefore cut back on fuel consumption and emissions.
  • In January 2002 Eurocontrol identified that the introduction of six extra flight levels (RVSM - Reduced Vertical Separation Minima) reduced CO2 emissions with one million tons, or three whole days' worth of air traffic in Europe.


In order to make the future air traffic controllers aware of environmental issues, the latter are integrated in the courses from the beginning of the training in our Training Centre. Upon completion of their Basic Training, the candidate air traffic controllers already have a good basic knowledge of the matter.

Currently, the environment is one of the 4 performance areas of the Single European Sky. The subject is complex because of its interdependent nature. An extension of a departure route to improve noise hindrance for instance, leads to an increase in fuel consumption and therefore in greenhouse gas emissions.


For more information about the environmental impact of aviation and the measures taken to reduce it, visit the website www.enviro.aero

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