COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES British Aerospace BAe 146 Series Aeroplanes AD/BAe 146/37 Landing Gear 12/91 Applicability: BAe 146 All Series 100, 100A, 200, 200A, 300 and 300A equipped with hydraulic fuses P/N ACM29100 (Mod states 1 or 2). Requirements: Action in accordance with technical requirements of British Aerospace Service Bulletin, CAA(UK) Mandatory, 32-130-70295C dated 27 September 1991. Compliance: Compliance required by 31 January 1992 on all aircraft equipped with hydraulic fuses, as defined in para 1 A (1) of the requirement document, that will have completed 4 000 flights on, or before 26 December 1991 since the introduction of these fuses. All other remaining affected hydraulic fuses must be modified by 29 February 1992. Background: Two cases have occurred of failure of the fork end fitting to the hydraulic fuses in the yellow hydraulic system. The same fuses are also fitted in the green hydraulic system. Due to mode of failure , there is a possibility of a double hydraulic system failure if a fuse fails in one system, followed by fuse failure in the other system.