British Airways, Delta Air Lines and US Airways are to conduct in-trail procedure tests, beginning in the second half of the year, using equipment from the ACSS joint venture between L-3 and Thales.

The in-trail procedure trials are part of Eurocontrol's Cascade programme that co-ordinates the roll-out of automatic dependent surveillance - broadcast across Europe.

Carriers participating in the tests are using the SafeRoute software suite of products developed by ACSS featuring ADS-B "in" capability that uses GPS to allow an aircraft to communicate its position to other aircraft, survey the location of other in-trail aircraft and communicate with ground stations.

British Airways is equipping four of its Boeing 777-200s with SafeRoute functionality while Delta plans to use three Boeing 767-300s in the programme. Five of US Airways Airbus A330s are pegged for the Cascade tests.

By using ADS-B in to communicate its position and monitor the location of other aircraft, the three airlines will be able to operate at a more efficient altitude in airspace not controlled by radar, which results in reductions in fuel burn and emissions.

On average a single request for a flight-level change warrants roughly seven calls from pilots to air traffic control, said ACSS president Kris Ganase. "In the end pilots don't bother doing that."

Unlike other next-generation air traffic control technologies, Ganase stressed that in-trail procedures is "essentially done in the aircraft", and is not dependent on ground infrastructure being in place to support its functionality. Noting that it amounts to the "easiest ADS-B function", Ganase believes "it brings you savings from day one".

He cited a Eurocontrol study showing that using ADS-B functionality for in-trail procedures could result in $450,000 in annual savings per aircraft. But Ganase acknowledges that is "just a report" and needs to be "backed by real trials".

Once Eurocontrol makes public data collected from the forthcoming trials, Ganase believes the results will incentivise other carriers to equip their aircraft with merging and spacing functionality to operate more efficient routeings. He predicts that by the end of 2012 all routes over the North Atlantic will be flown with in-trail procedures.

Source: Flight International