Evaluation of collision alerting system requirements for paired approach

In the paired approach concept, pilots are given responsibility to maintain spacing between aircraft on parallel approach. By placing the trail aircraft of an approach pair in a protection zone behind the lead aircraft, safety from collision and wake vortices can be managed. The size of the protection zone may be increased using a collision alerting system that commands the trail aircraft to break out should a blunder occur. This paper describes a study to evaluate the potential increase in protection zone size with the addition of an alerting system. A variety of approach conditions, blunder types, escape maneuvers, and system delay times were examined. Climbing-turn breakout maneuvers were found to be most effective in general, though the total system delay should not exceed 10 seconds. No significant alerting system benefits are possible when aircraft lateral separations are less than 1000 ft due to the limited time to take action. However, the need to separate aircraft during a missed approach suggests that collision alerting may be necessary.