Occurrence investigations consist of three phases, the factual data collection phase, the analysis phase and final report phase. Each phase usually takes about 3 to 4 months. In general, totally 11 to 12 months are usually required for the ASC to complete one  occurrence investigation. As for the major occurrence investigation, the ASC usually hopes to complete it within two years.

        Compared with other countries, the time period required for the ASC to investigate a major accident is obviously shorter. For example, the Hong Kong Civil Aviation Authority took near five years to complete the investigation of CI642 accident that occurred at Chek Lap Kok airport in 1999. The United States took about 4 years to complete the investigation of TWA Flight 800 accident and Canada took 4 years and 6 months to complete the investigation of Swissair Flight 111 accident. Compared with our country, they took much longer time. In addition, their manpower and resources are larger than those of the ASC.

To continuously improve and monitor the investigation schedule and efficiency, the ASC has launched the Investigation Management and Control System since 2010. Recent years, the ASC completed most of the occurrence investigation within 12 months which is recommendation by the ICAO Annex 13.