COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES DHC-3 (Otter) Series Aeroplanes AD/DHC-3/13 Propeller Counterweight Bearing Shafts NK Applicability: All models fitted with 3D40-227 propellers. Requirement: Action in accordance with De H Canada EB "O" No 39. Note: Canadian AD 56-13 refers. Compliance: Before installation on an aircraft following each propeller reconditioning.