With two-thirds of the impact of aviation on climate change believed to come from aircraft non-carbon-dioxide emissions, contrail prevention has a key role to play in curbing climate change. Since the beginning of 2021, Eurocontrol's Maastricht Upper Area Control Centre (MUAC), in partnership with the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), has been conducting a first worldwide live operational trial on contrail prevention aimed at mitigating non-carbon-dioxide 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 region 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, among other things, pertinent controller actions in specific circumstances, the precision of meteorological tools, and 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 2000 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 in the transition 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 has a long history of research into contrails and climate effects and is contributing with its expertise regarding 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.
A video of the trial objectives can be viewed below.