COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Sikorsky S-76 Series Helicopters AD/S-76/21 Amdt 1 Main Gear Box Assembly - Shaft and Spur Pinion Inspection and Retirement 3/83 Applicability: All model S-76 using 76351-09000 main gear box assemblies, prior to and including - 062. Document: Sikorsky Alert SB 76-66-16B. Note: FAA AD 82-06-51 Amendment 39-43-87 dated 5th March 1982 refers in part. Compliance: As per requirement document. Background: Manufacturer's Amendment "B" includes the -062 main gear box assembly incorporating the -104 shaft and spur pinions plus an additional inspection requirement.