COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Cessna 185 Series Aeroplanes AD/CESSNA 185/12 Engine Mount 7/68 Applicability: All models. Requirement: Visually inspect the engine mount for cracking, with particular attention to the rear engine bearers and rear cross tube. Compliance: At intervals not exceeding 100 hours time in service.