Solution-Space-Based Complexity Analysis of the Difficulty of Aircraft Merging Tasks

Air traffic controller workload is considered to be a limiting factor in the growth of air traffic worldwide. In this paper a new method of assessing controller task demand load will be developed and tested. Based on the hypothesis that operator workload is primarily caused by the difficulty of the task to be conducted, the concept of the solution space is described. For any particular air traffic control problem, the solution space describes the constraints in the environment that limit (and therefore guide) air traffic controller decisions and actions. The difficulty of that particular control problem can then be analyzed by considering the properties of the solution space. The task of merging an aircraft into a stream of other aircraft that fly along a fixed route is considered. An experiment has been conducted in which subjects were instructed to solve several merging problem scenarios of varying difficulty. After completing each scenario, subjects were asked to rate the difficulty of their task. High correlations are found between several solution-space properties and self-reported task difficulty.