Separation Discrimination in a Simulated Air Traffic Control Display

Abstract

Terminal area controllers made separation judgments concerning whether displayed pairs of aircraft were more than or less than the standard separation of 3 nautical miles (nm) apart. The pairs of aircraft varied with respect to their location on the air map, their relative orientation, and their separation. Two different map scales (40- and 55-nm radius) were used, and the controllers made 630 separation judgments on each map. The psychometric functions obtained indicated that the mean increment in separation required for discrimination was 0.14 nm. There were no significant differences in the psychometric functions for the 40- and 55-nm maps. Small, but operationally insignificant, effects on estimates of the separation between displayed aircraft were related to the location of the aircraft on the air map and to the relative orientation of targets.