COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Eurocopter AS 355 (Twin Ecureuil) Series Helicopters AD/AS 355/9 Main Gear Box Bevel Reduction Gear Module - Inspection of Bevel Ring Gear/Vertical Shaft Attachment Bolts 3/83 Applicability: All model AS 355 helicopters fitted with a main gearbox containing bevel reduction gear assembly, Part Number 355A.32.0600.00 and 01, not modified under A.M.S. 07.7082 or A.M.S. 07.7083. Document: AS 355 SB 05.05. Note: Bureau Veritas AD 82-178-8(B) refers. Compliance: PART 1: Within 10 hours time in service after 31st March 1983 every 50 hours thereafter, prior to compliance with Part 2: Carry out the visual check. PART 2: Within 300 hours time in service after 31st 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.