Research On Aircraft Collision Risk In RVSM Airspace

globally, while China began to implement RVSM on November 22th,2007.RVSM didn’t change the existing airspace an flight routes, six available flight levels were added between FL290 and FL410,for which delay and fuel cost would be reduced, more benefits would be obtained.However, reduced vertical separation increased aircraft collision risk and had impact on aviation safety. On one side,collision risk needed to be reasonably assessed against the defined target safety level; on the other side, aircraft performance requirements should be enhanced to meet RVSM operation standards; Non-RVSM approved aircraft may presumably fly in RVSM without applicable ATC clearances, which led to collision risk.Firstly,technical risk related to aircraft collision risk was researched, aircraft height keeping performance was analyzed, which included altimetry system error and flight technical error, vertical overlap probability was computed in terms of their respective probability density; technical collision risk was modeled based on Reich model combined with aircraft passing frequency and lateral overlap probability. Secondly, large height deviation events was analyzed and classified in details, operational risk computation model was also given, therefore total collision risk was modeled. In the second part of this paper, the impact of controller/pilots operation errors and in-flight contingency events on collision risk were researched by event trees. In the end, several kinds of corrective measures on collision risk were proposed.