Evaluation of Collision Avoidance Maneuvers for Parallel Approach

Two candidate evasion maneuvers were evaluated for use with a collision alerting system for independent closely spaced parallel approaches in instrument conditions. The two maneuvers were a wings-level climb and a climbing turn away from parallel trafŽ c. Pairs of aircraft on parallel approach were simulated by use of prerecorded trajectories covering a range of normal approach and blunder examples. Each example was repeated twice, with the endangered aircraft responding to alerts with either the climb-only or the climbing-turn evasion. The climbonly maneuver is shown to result in 38-times as many collisions as the climbing-turn for nominal alert threshold settings. It is possible to reduce the collision rate by adjusting threshold parameters, but the false alarm rate increases. The climb-only maneuver is shown to be uniformly less safe than the climbing turn for all parameter combinations. Results are illustrated with system operating characteristic curves.