After two and a half years, the Horizon Europe Green-GEAR project, focused on reducing the environmental impact of air traffic, has come to an end. Among the project partners was the Università di Trieste, represented by the research group of Prof. Lorenzo Castelli from the Department of Engineering and Architecture (DIA).

Currently, every flight crossing European airspace is subject to charges proportional to the distance flown and the aircraft’s weight, with rates varying depending on the country overflown. Flying through the airspace of Switzerland or the Netherlands, for example, entails significantly higher costs than crossing Ireland or Croatia.

These differences may lead airlines to choose longer routes to avoid more expensive airspaces: a strategy that results in higher fuel consumption and, consequently, additional and unnecessary carbon dioxide (CO₂) emissions.

With the aim of correcting these distortions and reducing the sector’s environmental impact, the contribution of the Trieste team focused on defining new charging models consistent with current European regulations, capable of mitigating disparities among States and encouraging more direct trajectories. The theoretical models were formulated using mathematical programming tools and validated on real traffic data provided by EUROCONTROL, a project partner.

Large-scale tests produced tangible results: a reduction of up to 1.46% in flown distance and up to 1.44% in CO₂ emissions. Considering that more than 10 million flights operate in Europe each year, even apparently small percentages translate into millions of tonnes of CO₂ avoided. Recent estimates indicate that flights departing from European airports alone generate between 130 and 140 million tonnes of CO₂ annually.

“Working on charging mechanisms that may appear purely technical actually means intervening structurally in the system,” Prof. Castelli emphasized. “By reducing economic disparities among national airspaces, it is possible to encourage more direct routes and achieve significant environmental benefits without compromising operational efficiency.”

The professor also acknowledged the key contributions of post-doctoral researcher Andrea Gasparin and PhD candidate Fulvio Vascotto, who worked on the project alongside him.

Green-GEAR represents the tenth European project developed by the UniTS research group over the past twenty years, always in collaboration with major continental stakeholders in the sector, and focused on the mathematical optimization of air traffic management.

The new Director of the Department of Engineering and Architecture, Giorgio Sulligoi, highlighted the strategic importance of this research, which is closely aligned with the European Commission’s objectives to reduce the climate impact of industrial activities, including air transport: “This is a crucial field of research for the ecological transition of the aeronautical sector. We are particularly pleased with the strong positioning of our group within the European landscape, further confirmed by the recent funding of a new Horizon Europe project that will extend the analysis beyond CO₂ alone, considering additional effects such as contrails and nitrogen oxide emissions.”

Most recently, the approval of FairSky has been announced. The project will broaden the analysis to the overall climate impacts of air traffic and will further strengthen UniTS’s role in European research on optimization and sustainability in air traffic management.