Safely reducing aircraft separation distances

With the steady increase in air traffic, civil aviation authorities are under continual pressure to increase aircraft handling capacity. One potential approach is to reduce the separation distance between aircraft at take-off and landing without compromising safety.

Finishing on 31 December 2005, IST project ATC-WAKE participants aimed to develop and build an integrated platform for ATC (Air Traffic Control) that would allow variable aircraft separation distances, as opposed to the fixed distances presently applied at airports.

The present minimum separation of six nautical miles for small aircraft (coming in behind a larger one), and three nautical miles for larger aircraft is designed to counter the problems aircraft can encounter in the wake of larger types. If these fixed distances can be reduced in favourable weather conditions without compromising safety, then an airport’s aircraft-handling capacity increases accordingly.

The ATC-WAKE platform aims to manage separation distances down to 2.5 nautical miles, in perfect weather conditions, for all aircraft types regardless of size. "We have tested the system with air-traffic controllers from five different countries at the national aerospace laboratory NLR in Amsterdam," says project coordinator Lennaert Speijker of NLR.

The ATC-WAKE system integrates weather and wake sensors, weather forecasting, wake-vortex prediction system, aircraft-spacing predictors and the air-traffic-controller interface. When used with planned new European harmonised safety regulations, it should be able to provide airports and aircraft handling organisations with significant increases in accuracy and aircraft-handling capacity, while maintaining safety.

Participating air-traffic controllers were directly involved in selecting the best method for on-screen display of aircraft position information. All chose the ‘Variable Wake Vortex’ method of display as the best solution. "We set up various real-time simulations on the system, and the controllers were all very positive about the results," says Speijker.

A key requirement for the researchers was that the platform be interoperable with existing ATC systems at airports. Meeting this target was an essential step towards the development of an integrated ATC decision-support system at airports, one that would enable air-traffic controllers to apply weather-based aircraft separation safely.

With the project now in its closing phase, the challenge faced by researchers is to take the next step and get the operational concept tested live at an airport. Project partner Eurocontrol Experimental Centre has lead the work on ensuring operational acceptability. And an approach to Madrid airport has lead to the planning of follow-up project, now in the approval stages, to test the system in a live environment.

ATC Wake contact:
Lennaert Speijker
Stichting Nationaal Lucht- en Ruimtevaartlaboratorium
Mathematical Models and Methods Department
Anthony Fokkerweg 2
PO Box 90502
NL-1059 CM Amsterdam
The Netherlands
Tel: +31-20-5113654
Fax: +31-20-5113210
Email: speijker@nlr.nl
http://www.nlr.nl/public/en/index.php?pid=6100

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