COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Beagle B121 (Pup) Series Aeroplanes AD/BEA 121/6 Fuel Tank Non-Return Valves 2/71 Applicability: All Series 1, 2 and 3 aircraft which do not have non-return valve P/N 703-AA-25 fitted to each fuel cell outlet connection. Requirement: Action in accordance with Beagle SB B121/21. Compliance: Within 100 hours time in service after 26 February 1971.