Supervisory control: Air traffic control specialist performance in shared versus traded states

The National Airspace System (NAS) is currently undergoing a restructuring in order to reduce flight delays and to increase airspace capacity, flight predictability, process visibility and safety. In general the reduction of constraints and the redistribution of information, authority and decision making capability has been termed "free flight." One aspect of this process of restructuring involves exploring the possibility of delegating some portions of aircraft separation authority to the flight deck. This process of delegation for self-separation to the flight deck and its implications for pilots and air traffic controllers was the topic of this simulation experiment. Seventeen Air Traffic Control Specialists performed in shared and traded supervisory control states. Shared control is the performance of a task by a human operator with the concurrent assistance of automation. Traded control is the process of shifting the handling of a task by either the human operator or automation. In the shared condition, the specialists monitored the airspace with the assistance of a conflict probe. In the traded condition, the specialists performed a secondary task, in addition to monitoring the traffic with the assistance of the conflict probe. The researcher also manipulated the percentage of planes in free flight, 80% and 100%. Indices included controller workload, separation performance, secondary task performance, and questionnaire data. Results indicated that workload was significantly higher in the traded condition, and that there were less separation violations in the shared condition. The participants also performed better on the secondary task in the Traded/100% condition than the Traded 80% condition. The study was funded by the FAA and NASA.