Emma Kelly/LONDON

The UK's National Air Traffic Services (NATS) has pioneered the use of voiceless oceanic flight clearances across the North Atlantic with the implementation of Oceanic Route Clearance Authorisation (ORCA).

Full-scale implementation of ORCA follows a successful trial and development phase which started in 1998. NATS initially worked with American Airlines to resolve early technical issues, which included ground system performance and avionics issues.

Some 21 carriers - including Air Canada, Air France, Air New Zealand, British Airways, Lufthansa, Scandinavian Airlines, Swissair and Virgin - have become users since late last year. The service allows oceanic flight clearances to be made via VHF datalink instead of voice radio telephony (R/T) in the Shanwick flight information region.

Around 40% of westbound traffic across the North Atlantic uses ORCA and the figure is growing, says NATS. Iberia has recently tested ORCA, and a further eight carriers are in the testing phase, says Keith Richardson, NATS manager of ATC oceanic.

NATS is also encouraging corporate aircraft to go on line.

ORCA is the only completely voiceless method of oceanic clearance delivery over the North Atlantic and possibly the first in the world, says NATS. The service was introduced in response to airline requests to improve the clearance delivery process.

Datalink delivery of clearances overcomes the problem of R/T congestion and is also intended to reduce cockpit and controller workload, increase delivery speed of clearances and reduce transmission errors. Other air traffic service providers, including Nav Canada, are showing interest, says Richardson.

ORCA implementation is the latest move towards datalink communications. In late January, NATS and Nav Canada implemented automatic dependent surveillance (ADS) waypoint position reporting in the Gander and Shanwick regions (Flight International, 6-12 February).

The transition to ADS position reporting has gone smoothly, says Richardson. He adds that it is saving six routine position calls on each flight across the Atlantic. Further datalink initiatives are planned, including controller-pilot datalink communications trials in conjunction with Nav Canada in the North Atlantic from next month.

Source: Flight International