During large parts of the year, European airspace operates at or beyond capacity, leading to substantial delays and inefficiencies both for passengers and operators, estimated in 1988 to be at US$ 5 billion. Despite the introduction of new technology and planning methods to ameliorate the problem, the continuous growth in air traffic means these delays and inefficiencies remain. The design, planning and management of European airspace is a highly complex task, involving issues of national sovereignty, the interaction of civil and military uses, as well as detailed technological and operational considerations. Prime difficulty is the meaning of the term airspace capacity, and the fact that this is determined by the acceptable workload levels of the air traffic controllers. This workload is the sum of both physical and mental tasks undertaken by the controller from the air traffic control environment - due to the effect of both the air traffic attributes (e.g. the proportion of ascending aircraft) and those due to the physical and geographical features of the airspace (e.g. the volume of airspace controlled) - and from within the controller. In recent years, a range of modelling tools have been developed to assist in different aspects of airspace management, and despite the many factors inhibiting the greater adoption of comprehensive air traffic planning techniques, this paper considers the use of one such tool of controller workload modelling - the Reorganised ATC Mathematical Simulator (RAMS) developed by EUROCONTROL - which forms part of a PhD. thesis, to derive a better understanding of airspace capacity and to help in better management of airspace. Therefore the objectives, and structure, of this paper are as follows: (1) assess the definitions of airspace capacity as a function of controller workload; (2) introduce a new approach to modelling the capacity of airspace sectors as a function of controller workload using the RAMS model; (3) using the method outlined above, estimate the functional relationship between the controller workload and the salient sector, route and traffic variables for Europe's ATC sectors; and (4) provide alternative estimates of capacity for the ATC sectors in Europe and to understand how within these estimates, capacity is related to sector, demand and control characteristics.
Samenvatting