COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES DHC-2 (Beaver) Series Aeroplanes AD/DHC-2/12 Amdt 2 Left and Right Wing Intermediate Rib Assembly Stations 15.50, 29.00 and 42.50 - Inspection and Modification 10/84 Applicability: All model DHC-2 aircraft. Requirement: De Havilland of Canada EB Series "B" No. 35. Compliance: Unless already accomplished inspect within 250 hours time in service after 17 September 1984 and thereafter at intervals not exceeding 500 hours time in service until modification 2/1497 is incorporated. Background: This Directive is amended to correct a rib station number, include an additional rib assembly and clarify inspection and modification requirements.