COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bell Helicopter Textron 47 (All Variants) Series Helicopters AD/BELL 47/59 Main Rotor Blades 10/65 Applicability: All model 47 series with metal main rotor blades. Requirement: Carry out a visual inspection for cracking of the upper and lower surfaces of the main rotor blades adjacent to the outboard extremity of the root reinforcement doublers at the trailing edge. Compliance: Before 1500 hours blade time in service and thereafter at intervals not exceeding 100 hours time in service.