COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Eurocopter AS 350 (Ecureuil) Series Helicopters AD/ECUREUIL/21 Amdt 1 Main G/Box Bevel Reduction Gear Module 11/85 Applicability: All model AS 350 helicopters fitted with a maingear box containing the bevel reduction gear assembly part number 350A32.0300.00, 01 and 02, not modified under A.M.S. 07.7082, A.M.S. 07.7083 or A.M.S. 07.7098. Requirement: AS 350 SB 05.10. Rev. 1. Note: Bureau Veritas AD 82-176-28(B) refers. Compliance: PART 1: Within 10 hours time in service after 31st March 1983 and every 50 hours, prior to compliance with Part 2, carry out the visual check. PART 2: Within 300 hours time in service after 31 March 1983, carry out the screw tightening check, as a one time only inspection. PART 3: Every 300 hours time in service, after compliance with Part 2, carry out the visual check. Background: The manufacturer advises that there have been several cases of sheared and loose bolts, securing the bevel ring gear to the vertical shaft, found during maintenance operations. This directive is amended to add modification A.M.S. 07.7098 to the list of exclusion in the aircraft applicability.