Planning for the development of a future air traffic control system, or for the improvement of an existing system, requires a substantiated appreciation of the capacity and performance of the present system and of the projected future system.

With the growing volume of air traffic and the advancement of modern technology, ATC planners are concerned with making decisions relating to the organisation, development and control of an increasingly complex and sophisticated dynamic system. In many instances it is no longer possible to decide solely on the traditional basis of experience, intuition and “rule of thumb”, especially when the decision involves the selection of the best of several alternatives, involves the employment of very large sums in capital investment and affects the safety and security of large numbers of human lives. Under these circumstances it has become essential to turn to the Operational Research techniques which have been developed and which are now readily available to derive data on which sound decisions may be based.