COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES British Aerospace BAe 125 Series Aeroplanes AD/HS 125/58 Landing Gear Hydraulic System - Inspection and Modification Applicability: All models without Modification No. 252837. Document: British Aerospace 125 SB No. 32-190. Compliance: Before 1 April 1982. 11/81 Background: Blockage of a landing gear restrictor valve may prevent lowering of the gear by either the normal or the auxiliary hydraulic system. Filters are introduced at each side of the restrictor valves.