Airspace Safety Assessment

        Background

        According to ICAO’s requirement, regions where RVSM is implemented should meet the requirement of safety management system and conduct safety assessment.A safety assessment consists of estimating the risk of collision associated with RVSM and comparing this risk to the agreed RVSM safety goal, the TLS.

        Regions where RVSM is implemented should establish the long-term safety assessment and monitoring mechanism and carry out airspace safety assessment regularly.

        Target Level of Safety

        An RMA supports the implementation and continued safe use of RVSM within adesignated airspace. In the context of RVSM, “safe” has a quantitative meaning: satisfaction of the agreedsafety goal, or target level of safety (TLS). Section 2.1 of Doc 9574 describes the safety objectivesassociated with RVSM implementation and use. Paragraph 2.1.4 of Doc 9574 specifies that the TLSattributable to aircraft height-keeping performance, or the technical TLS, should be no greater than2.5 x 10-9 fatal accidents per aircraft flight hour. Paragraph 2.1.6 specifies that the safety goal for overallrisk in connection with RVSM should be set by regional agreement, with several examples of precedentindicating that the value used in practice should be consistent with 5 x 10-9 fatal accidents per aircraftflight hour.

       Safety Assessment Methodology

       China RMA applies the Reich collision risk model recommended by ICAO to conduct the safety assessment. The nationwide safety assessment is conducted semiannually.

       Data Preparations for Conduct of a Safety Assessment

       China RMA collectedTraffic Sample Data (TSD) every December and Large Height Deviation (LHD) data on a monthly basis.