Collision and missed approach risks in high-capacity airport operations

A study is made to develop a risk model for airport landing operations. Particular emphasis is placed on simultaneous use of closely spaced parallel runways and on reduction of longitudinal separation on final approach. Based upon certain simplifying assumptions, the missed approach and collision rates are evaluated. For the parameters considered it is found that a safe separation distance for parallel runways is approximately 2500 ft. Further, an acceptable missed approach rate can be maintained if the average spacing at the runway threshold is 62 seconds without speed adjustments on final approach; with some speed adjustments, 55 seconds is sufficient, assuming a runway occupancy time of 40 seconds. A description is given of the type of studies required in order to validate the conclusions suggested by the model.