Abstract: In order to study influence of yaw angle on collision risks between two aircraft in parallel approach yaw, a collision risk model of parallel approach in yaw was established by using Event model and probability theory. Then by analyzing transformation of the model's collision box, variation law of extended collision box section with time t and yaw angle α was obtained. In the meantime, collision probability ratio R was introduced in order to deduce formula for risk calculation, and it was defined as the ratio of transformed collision box volume to that of original model. Finally, risk analysis was conducted with parallel approach yaw of runways outside Beijing Capital Airport as an example. The calculation results show that with given aircraft size and runway interval, collision risk will grow as yaw angle increases in the range of [0,90 °]. It can only meet safety target when yaw angle is smaller than 32 °.

Key words: air transportation, collision risk, Event model, parallel approach, yaw