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 125/55 Fuel Filler Neck Flap Valve - Installation 7/81 Applicability: As detailed in the requirement document. Document: British Aerospace 125 SB No. 28-60-(2465), Rev. No. 2. Compliance: Before 31 January 1982. Background: A rubber flap valve is fitted to each of the fuel tank filler necks to minimise the inflight effects of an improperly closed fuel filler cap.