抄録
RVSM, which is the vertical separation minimum reduced from 2,000ft to 1,000ft at flight levels (FL) between 290 and 410 inclusive, was implemented on 30 September 2005 within the Japanese domestic airspace for efficient aircraft operation. As a result of safety assessment for the airspace in assumed RVSM environments using a collision risk model, an estimate of collision risk averaged for whole target airspace met a maximum allowable level of collision risk, i.e. 2.5×10^<-9> [accidents/flight hour], called the technical Target Level of Safety (TLS). However, a local collision risk value for G581 route didn't meet the TLS. The G581 route system was restructured for reducing aircraft passing frequencies by traffic flow division. Using flight progress data, the passing frequencies for the route system were estimated every month. An estimate of the collision risk after the restructuring for the route system meets the technical TLS. The estimate after the implementation of RVSM is half of that before the implementation. It's one fortieth of the estimate before route restructuring.
