En-route air traffic management: An alternative basis

With advances in navigation and communications technology, it has been argued that aircraft might be allowed ‘free flight’ abandoning the current system of air routes dictated by navigational aids. It has also been argued that it should be possible to issue departure clearances for commercial aircraft that constitute a ‘seamless agreed contract’ or a ‘tube of flight’ from origin to destination. This paper describes a quantitative analysis of air traffic over Europe, and demonstrates that a ‘seamless’ clearance system for aircraft is unworkable without a considerable improvement in the predictability of the flight patterns, and in particular, the predictability of the times of arrival of aircraft at points where two flight paths intersect.