COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bell Helicopter Textron 205 Series Helicopters AD/BELL 205/52 Tail Rotor Trunnion Bearing Housing 9/86 DM Applicability: All model 205A and 205A-1 helicopters fitted with kit P/N 212-704-129-101 (refer SI 212-68). Requirement: Action in accordance with Bell Alert Service Bulletin No. 205-86-24, Revision A. Compliance: Part I of the Requirement Document: Within 25 hours time in service or seven days whichever occurs first after 6 August 1986 and thereafter at intervals not exceeding 25 hours time in service or 7 days, whichever occurs first, until Part II is complied with. Part II of the Requirement Document: Within 150 hours time in service or 60 days whichever occurs first after 31 July 1986. Background: A trunnion bearing housing end web has been found below specified dimensions. Failure of the housing caused excessive tail rotor vibration and loss of control.