With the rapid increase of air traffic flow in recent years, fight conflict have become more and more serious.So it is very necessary to make a study about how to avoid flight collision in the air.

• 摘要空中交通的飞行冲突问题日益严重，笔者认为对空中飞行碰撞风险问题研究非常必要，旨在建立进近程序间隔评估模型。