Developing a generic metric of terminal airspace traffic complexity

This article develops a generic metric for measuring the complexity of a given terminal airspace (TMA). The metric includes static and dynamic complexity, both consisting of the complexity component for arriving and departing traffic. The main objective of the developed metric is as follows: evaluation of particular alternative solutions for airspace organisation and design and related air traffic complexity under the given circumstances, which could be used for planning purposes at the strategic and the tactical level. For this reason, the proposed metric reflects the expected complexity over a certain time period, rather than the current value of complexity. The main factors influencing complexity of a given TMA are: configuration of TMA, which implies among other factors, the number and length of arrival/departure trajectories, the airport(s) runway system capacity, air traffic volume, aircraft fleet mix, spatial distribution of traffic and the air traffic control separation rules. Unlike most other approaches, the one presented in this article disregards the air traffic controller workload issue from explicit consideration, but indicates the level of complexity which could influence the workload that he or she could be faced with under the specified circumstances. The output consists of complexity values dependent of the configuration, i.e. three-dimensional geometry of the given TMA and approach/departure trajectories in it, air traffic volume, aircraft fleet mix and the spatial distribution of traffic. The developed complexity metric has been applied to TMA traffic around London Heathrow Airport, UK.