Defining Appropriate Inter -Aircraft Separation Requirements

In order to maintain minimum separation standards between two aircraft, proper avoidance maneuvers must be initiated before their relative separation reaches the minimum separation due to aircraft dynamics, controller and pilot response delays, and other delays. This paper presents the concept and a systematic procedure for the calc ulation of required action thresholds, which is the time or distance when the conflict resolution process must begin in order to maintain minimum separation requirements. It sets an upper boundary or latest alert time for the conflict detection and resolu tion process. In this paper, 5 main segments in the process of conflict resolut ion are identified and modeled: s tate information acquisition, comprehension and decision, communication, pilot response, and aircraft maneuver. Then, the models of the five segments are brought together in a simulation where a robust aircraft maneuver time can be calculated through extensive simulations. The models and simulation are then used to determine the required action threshold. Three example scenarios are studied to illustrate the determinations of appropriate required action thresholds.