COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bell Helicopter Textron Canada (BHTC) 206 and Agusta Bell 206 Series Helicopters AD/BELL 206/51 Amdt 2 Vertical Fin Support Forgings 8/93 Applicability: All models with serial numbers referenced in the Requirement Documents. Requirement: 1. For aircraft equipped with a vertical fin assembly which has an external doubler installed on the left-hand side, adjacent to the support forgings - inspect and modify in accordance with Bell Alert Service Bulletin 206-91-60, dated 28 June 1991, or Agusta Bollettino Technico 206-202, dated 20 July 1992, as appropriate. 2. For aircraft equipped with a vertical fin assembly which does not have a doubler installed - inspect in accordance with Bell Service Bulletin 206-01-73-5 Revision A, dated 21 September 1973. Note: FAA AD 73-21-3 refers. Compliance: For Requirement 1: Unless already accomplished, at the next inspection for issue of a Maintenance Release (this shall mean a period not exceeding 110 hours time in service) or by 19 August 1993 whichever occurs first. For Requirement 2: Unless already accomplished within the last 1000 hours, at the next inspection for issue of a Maintenance Release (this shall mean a period not exceeding 110 hours time in service) or by 12 March 1991 whichever occurs first. Background: Amendment 1 was the result of further instances of cracking in the fin support forgings. For those aircraft fitted with a doubler, action was provided to alleviate unacceptable stress in the forgings. Amendment 2 has been raised to include the Agusta Bell model 206.