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-3/10 Exhaust System NK Applicability: As detailed in Requirement Document. Requirement: Action in accordance with De H Canada EB "O" No 19. Note: Canadian AD 56-12 refers. Compliance: Forthwith.