Impact of ADS-B on Controller Workload: Results from Alaska's Capstone Program

The Capstone program introduced avionics in Alaska that included ADS-B equipment, starting in the year 2000. The program succeeded in equipping 208 aircraft in the Yukon-Kuskokwim Delta by the end of 2004, resulting in Capstone-equipped aircraft accounting for nearly 100 percent of Part-135 operations by airplanes based in that region. This paper estimates the impact of the use of Capstone equipment on controller workload. It summarizes the results of a controller survey regarding the effect of Capstone equipment on controller tasks, and provides quantitative results regarding the effect of ADS-B equipment on controller workload. From the survey 57 percent of controllers indicated that they needed less time providing IFR separation services than without ADS-B, and 79 percent of the controllers felt that the overall efficiency of their operation had increased with ADS-B. An analysis of flight progress strips showed that the currently deployed Capstone equipment, when operating properly as required by ATC, would provide an 18 percent reduction in controller communications workload. The analysis also indicated that if all the aircraft in the Y-K Delta were properly equipped, the reduction in communications workload would be 26 percent.