A collision risk model for a crossing track separation methodology

A mathematical model for estimating collision risk for a method of separating aircraft on intersecting tracks is proposed. The model includes an allowance for a small proportion of crossings to be made in the absence of any control. Numerical results are presented for some typical en-route airway intersection points in the Tasman Sea area. Also presented is a sensitivity analysis with respect to the crossing angles, Required Navigational Performance (RNP) values, and aircraft speed variations. Some justification for the assumed probability distributions is also given.