Single European Sky trajectory is plotted

Capacity, efficiency and environmental gains could be wiped out if Europe fails to develop infrastructure at key hubs

Failure by states to expand runway capacity at major airports would negate almost all the capacity, efficiency and environmental gains that are planned for Europe's future air traffic management system, according to a just-released strategic planning document that has been accepted by Eurocontrol and the European Commission.

Radical differences to the way in which individual air traffic movements are managed has the potential to increase en-route traffic capacity by a factor of three, but failure to develop airport infrastructure, especially at major hubs, could render the improvement pointless, says the report. Delivered by the Single European Sky SESAR multi-disciplinary planning team, this report - entitled "ATM target concept" - is the third in a sequence of six strategic plans due to be delivered by mid-2008 under the "SESAR definition phase".

The target concept changes ATM from the traditional system, under which air navigation service providers (ANSP) imposed solutions on the airspace users, to one in which the users "own" an ideal four-dimensional (4D) trajectory (the fourth dimension is time) for every flight. There will be a gradual transition process, says the report, but the target will be met across the entire system by 2020. Airlines will be able to assume their flights can fly what has been dubbed "the business trajectory" - the best trajectory from the business point of view.

Since its inception the SESAR programme's objective has been to shift the way the ATM system works from being provider-centric to user-centric, and this "target concept" plan describes the means by which this can be achieved. The concept assumes each flight will fly an ideal trajectory: that includes a direct route from departure to destination, flown at the best speed at the best height.

The latter may allow the crew the option of a fuel-efficient cruise-climb rather than adherence to stepped flight levels. If the ideal trajectory cannot be flown, the alternative will be the most efficient available.

The principle upon which success will depend, says the SESAR report, is the establishment of a network-centric communications system, known as a "system-wide information system" that will enable collaborative decision-making in which all the parties continuously participate: that includes the flight itself, the airline, the departure and destination airports, and the ANSPs. The collaborative decision-making system will have to flexible enough to adapt to unexpected occurrences of all types, like weather, runway blockage, and aircraft or ANSP technical problems. There will be an over-arching network operations plan that will ensure demand does not exceed capacity, says the report.

Eurocontrol warns, however: "Capacity and cost-effectiveness targets in some areas (major hub airports and high density airspace) can only be achieved through supplemental actions [like] additional runways and functional airspace blocks."

Finally, the surveillance technology and controller tools (see box) have to be sufficiently smart to ensure aircraft trajectory separation the aircraft navigation systems and on-board equipment have to be capable of flying aircraft 4D trajectories with unprecedented precision and the ground and air safety-net systems must be perfectly coordinated to prevent collision if the system breaks down.

Source: Flight International