Information Transfer in Pilots' Use of a Collision Avoidance System

Abstract

This paper describes a study of pilots' use of the Traffic-alert and Collision Avoidance System. Three levels of information on the location of other air traffic were presented to different groups of airline pilots. (These levels represent the approaches taken by several airlines who have installed the collision avoidance system for an in-service evaluation.) Current airline flight crews flew a Boeing 727 simulator for eight flights with a set of encounters with other aircraft.

To ensure safe separation from the approaching aircraft, the collision avoidance system commands a climb, a descent, or a reduction in rate of climb or descent. Aircraft separation was effective when the system was in use; no aircraft came within 200 feet vertically and 1000 feet horizontally.

No measure of response time showed performance effects across display conditions. Response accuracy, as measured by the overshoot in rate of climb or descent, was significant: the mean for condition 1 (no traffic information) was 2246 feet/minute, condition 2 1220 feet/minute, and condition 3 1304 feet/minute (F=4.57, df=2,64, p<.05). However there were no resultant differences in the amount of altitude change.

No learning effects were observed. Differences in flight experience did not contribute to the performance difference found.

The results of this research represent pilot behavior when introduced to the Traffic-alert and Collision Avoidance System. The findings of this program also have more fundamental importance in addressing how much and in what manner information should be presented to flight crews.