Nats said: ‘In radar airspace there is either a five nautical mile or three nautical mile minimum separation laterally between aircraft, however, over the North Atlantic it is 60nm laterally and for aircraft following on the same route it is based on time – essentially 10 minutes apart. For aircraft crossing another aircraft at the same level it is increased further to 15 minutes.’
And aircraft are given fixed speeds to make sure they don’t catch up with the plane in front.
The tracks are set up after requests for preferred routeings are received from airlines.
Nats positions them according to winds, costs and airspace restrictions and labels them from ‘alpha’ upwards.
Carriers must then follow the track structure.
However, a revolution is about to take place that will mark one of the biggest transformations in transatlantic flight in decades.