With a total of 466 direct routes published in the upper airspace controlled by the Karlsruhe Upper Area Control Centre of DFS Deutsche Flugsicherung and EUROCONTROL’s Maastricht Upper Area Control Centre, the network of cross-border routes available as a flight plan option has expanded considerably, creating a large-scale free route airspace over Belgium, most of Germany, Luxembourg and the Netherlands. This results in significant savings for airlines and of CO2 emissions.
Figures published by the Free Route Airspace Maastricht and Karlsruhe (FRAMaK) project suggest potential yearly savings by airlines in the region of 1.5 million nautical miles, roughly equating to 9,000 tonnes of fuel. This will in turn lead to a reduction of CO2 emissions by approximately 30,000 tonnes. The project partners are the German air navigation service provider DFS Deutsche Flugsicherung, the European Organisation for the Safety of Air Navigation EUROCONTROL and Lufthansa.
FRAMaK is a pioneering project; the EU Regulation will require European air navigation service providers to offer direct and individual routes in the future. The project was sponsored by the SESAR Joint Undertaking. The results will be integrated into the Functional Airspace Block Europe Central (FABEC) Free Route Airspace Programme.
Modern trajectory-based air traffic management systems were required to be able to offer the new route options.
The FRAMaK project took existing direct routes and linked them across borders, expanded others, and created new ones, or optimised them as concerns their times of availability: 46 percent of the total 466 routes published are available 24 hours a day. The others only have limited availability, mostly weekends and nights.
The two control centres have exceeded the great circle deviation percentages mandated by the EU for the first Single European Sky reference period. The new routes allow for an average deviation of 1.7%, significantly lower than the 4.65% EU requirement. The great circle distance is the shortest path between the departure and destination airports on a globe.
The published routes also enable airlines to plan more efficiently, less fuel can be taken on board, and there will be fewer deviations from flight plans.
Normally, airlines plan their flights along predefined airways which are often significantly longer than the great circle distance. Airways are designed to offer the most capacity and availability possible. They avoid, for example, military training areas which are open to civil traffic only at certain times. In practice, air traffic controllers often offer pilots short cuts called tactical directs. However, aircraft have the amount of fuel on board that they would have needed for their originally planned routes which is significantly more than is needed to fly the direct routes. The weight of this excess fuel increases fuel consumption and reduces payload. Pilots may arrive at their destination earlier than expected which means they may need to fly holding patterns or wait on the ground for an aircraft stand to become available.
User Preferred Routes
Furthermore, the FRAMaK project examined individual flight routes called “User Preferred Routes”. For the direct route options are just the first step in the process of establishing actual Free Route Airspace. With the User Preferred Routes, airlines can choose freely and take dynamic factors such as weather, wind conditions or overcrowded airspace into consideration when planning flights. For the length of a route is not the only aspect that plays a key role in route planning. The project partners analysed 62 flights on six different connections including intra-European flights as well as transatlantic connections. The individual routes are already conceivable today in less complex airspace or at non-peak times. Further studies and further technological development are needed to facilitate them in complex and busy airspace.