Collision Risk Model around Intersection of Airways

In order to estimate the collision risk caused by variable nominal separation when two aircraft on intersecting airways are flying around the intersection, a collision risk model around the airway intersection was proposed by introducing a variable of arrival time interval. A method was given to estimate the collision risk around the intersection where the nominal separation changes with time. The results of a case study show the number of increased collision risk is 1.14710-7 when aircraft are flying on airways with one intersection; as the angle between flight paths increases, the collision risk decreases gradually at first, and then increases slowly; for three different combinations of speeds, the minimal values of the collision risk are all achieved in the interval (70, 75) of angle between flight paths. The proposed collision risk model can be used to calculate the increased collision risk caused by airway intersections and analyze the influence of the angle between flight paths on the collision risk.