Abstract: Contingency route is an important means of ensuring a certain amount of aircraft keep flying in the airspace of air traffic control zeros where the ground control units totally lose their service competence. A programming method of contingency route was developed in this paper on the basis of similar traffic flow pattern by analyzing the characteristic of traffic flow time series in busy waypoints. Furthermore, a hierarchical clustering method based on similarity measurement of Euclidean distance was used to analyze time series of different points in generalized airway networks according to the actual flight operating data in Beijing Area Control Center. Contingency routes were programmed for a certain controlled airspace in Beijing by selecting different distance threshold values combined with some composite factors such as route connection type and conflict points. With this method, a minority of aircraft can keep flying safety in the airspace of air traffic control zeros, and the working pressure of the ground control units can be reduced.

Key words: contingency route, time series, hierarchical clustering, traffic flow pattern, euclidean distance