SESAR members and partners recently validated free routing in one of Europe’s busiest and most complex airspace. The exercise was led by Skyguide in collaboration with DSNA, Eurocontrol, Lufthansa Systems and Sabre. The exercise demonstrated the operational feasibility and benefits of the free routing concept, as well as the minimum flight level and associated acceptable complexity level.

Taking place at the Skyguide premises in Geneva in February 2016, this real time simulation (RTS) focused on parts of French, Italian and Swiss airspace, using a validation platform equipped with advanced and trajectory-based controller support tools. A business trajectory flight planning iterative process was used from initial shared business trajectory submission to reference business trajectory use during flight execution phase.

Trajectories were calculated with maximum of freedom for airspace users and shared using the new extended flight plan format by the flight operations centres (FOC) of Lufthansa Systems and Sabre. They were then processed by the Network Manager and ANSPs before being used during the simulation session. The Network Manager assessed the proposed trajectories with regards to capacity and congestion and proposed regulations accordingly.

More than 20 controllers (Skyguide, ENAV) and 16 simulator pilots participated in 20 simulation runs assessing different scenarios (minimum FRA FL305+/FL365+, military activities, different weather conditions). A state-of-the art ATC system including advanced controller support tools (conflict detection tool, monitoring aids, trajectory editor, electronic coordination, what if function, controller pilot data-link communication…) was used by the air traffic controllers involved in the exercise.

Free route flight planning area covered almost ECAC, however the simulated operational environment included one of the most complex airspace in the core area: Swiss airspace (Skyguide), portion of Italian (ENAV) and French (DSNA) airspace.

Initial results show that controller support tools for free route environment are almost there, however acceptability of the free route concept varies depending on the minimum free route flight level and is subject to concept refinement in order to make it more efficient, robust and manageable.

From FOC point of view, in contrast to trajectories planned on the currently used ATS route network, the free route concept enables the airspace users’ flights to plan/re-plan a trajectory using user-defined segments connecting published and/or user-defined lat/long points. This allows for much more flexible routing options, providing the base for airspace users to be substantially more cost or fuel efficient: Now they can plan trajectories optimally suited to meet their business/mission needs, as Lufthansa Systems pointed out in an extensive analysis of the free route trajectories. In addition, the exercise provided precious insight on how free route should be best implemented in the FOC system to allow airspace users to take maximum advantage of free route.

From Network point of view, it shows that free route trajectories over a wide area create large number of “hotspots” that are very difficult to absorb and therefore create delays that are not acceptable by airspace users from cost and operational efficiency perspectives. Therefore operating methods/procedures and tools will need adaptation to manage hotspots and share information amongst stakeholders.

In summary, this exercise provides a first validation step of free route in a complex environment and highlights issues/limitations of the free route concept that will be taken on board in SESAR2020 to enable benefits expected by airspace users with such concept.