Press release

Mitigating the climate impact of non-CO₂ emissions

MUAC Press Prelease image

Air traffic managers and scientists unveil first conclusions of 2021 contrail prevention live trial in EUROCONTROL MUAC airspace.

With two-thirds of the impact of aviation on climate change believed to come from aircraft non-CO2 emissions, contrail prevention has a key role to play in curbing global warming.

Since the beginning of 2021, EUROCONTROL’s Maastricht Upper Area Control Centre (MUAC), in partnership with the German Aerospace Center (DLR), have been conducting a first worldwide live operational trial on contrail prevention aimed at mitigating non-CO2 emissions.

In total, 209 aircraft trajectories were included in the trial over the past 10 months. During the trial, the technical feasibility of contrail prevention, the accuracy of ice-super-saturated regions forecasts and the operational feasibility of vertical contrail prevention at specific traffic loads were carefully evaluated. The trial also revealed practical problems which need to be resolved if ATM measures are to be implemented to reduce the climate impact of aviation in the future. These concern inter alia appropriate controller actions in specific circumstances, the precision of meteorological tools, or real-time feedback processes.

The trial runs were performed on selected dates, after 18:00 local time and during the night. A team of MUAC and DLR planners interpreted the predicted weather regarding ice-super-saturated regions and clouds, and gave instructions to controllers to avoid specific regions by means of vertical clearances of up to 2,000 feet. A contrail prevention system was set up to prepare and implement operational procedures aimed at contrail prevention, and to start validating the methodology with satellite image analysis provided by DLR.

Other means of avoiding ice-super-saturated regions, such as pre-tactical planning, lateral avoidance or changes in aircraft equipment, were outside the scope of the 2021 MUAC/DLR contrail prevention trial. Aircraft which requested cruising altitudes above or below levels of predicted ice-super-saturated regions were cleared through these regions during climb or descent. Depending on the final results, a different approach may be proposed in the future.

The MUAC/DLR trial on contrail prevention is one contributor and component in a much wider picture of mitigating climate change. It is an important milestone from theory to practice and a stepping stone from science to engineering. Scientists and ATM managers hope that the results of this trial will contribute to sparking decisions for the future of aviation.

DLR (the German Aerospace Center) has a long history of research into contrails and climate effect and is contributing with its know-how about the physics of the atmosphere, the modelling of contrails and contrail cirrus, and satellite image analysis with a view to evaluating the effectiveness of contrail prevention.

EUROCONTROL’s MUAC also has a long tradition of working on environmental topics, especially regarding fuel consumption. MUAC was at the origin of the European direct route network.

Number of flights affected daily during the trial

Number of flights affected daily during the trial

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Note to editors


Operated by EUROCONTROL on behalf of four States, EUROCONTROL’s Maastricht Upper Area Control Centre (MUAC) provides civil and military cross-border air traffic control in the upper airspace of Belgium, Luxembourg, the Netherlands and north-west Germany (from 7.5 km or 24,500 feet). Some 1.9 million flights (pre-COVID-19 figures) pass through MUAC’s area of responsibility each year, making it the third busiest air traffic control facility in Europe in terms of traffic volume. During the summer, peak days see over 5,700 flights. MUAC’s international area of responsibility is a perfect example of the simplification and harmonisation of airspace in Europe and is fully in line with the objectives of the Single European Sky.

About DLR

DLR is the Federal Republic of Germany’s research centre for aeronautics and space. We conduct research and development activities in the fields of aeronautics, space, energy, transport, security and digitalisation. The German Space Agency at DLR plans and implements the national space programme on behalf of the federal government. Two DLR project management agencies oversee funding programmes and support knowledge transfer.

Climate, mobility and technology are changing globally. DLR uses the expertise of its 55 research institutes and facilities to develop solutions to these challenges. Our 10,000 employees share a mission – to explore earth and space and develop technologies for a sustainable future. In doing so, DLR contributes to strengthening Germany’s position as a prime location for research and industry

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