ABSTRACT
Although the global air traffic control (ATC) system represents one of the most complex human-machine systems ever developed, ATC upgrades are having a difficult time keeping pace with the ever-increasing demand for air transportation. By even conservative projections, air traffic is expected to rise by some 40% over the current decade. Unfortunately, increasing "sectorization" of the airspace — simply carving up the total airspace into smaller regions—does not solve this problem, as increased intersector communication and coordination demands are likely to deny any net gain in system throughput. The goal of designers, therefore, has been to create future ATC systems that permit the individual controller to handle more aircraft at present or better levels of safety. This goal is reflected in current efforts to develop new automated tools (e.g., decision-aiding conflict probes), interfaces (e.g., datalink communication modes), and operational concepts (e.g., free flight, in which aircraft assume greater responsibility for route selection and separation assurance). Historically, one of the chief design criteria for such developments has been the mental workload they impose on the controller.
