COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bell UH-1 Series Helicopters AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/UH-1/5 Amdt 1 and issues the following AD under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section. AD/UH-1/5 Amdt 2 Tailboom Vertical Fin Spar 1/2001 TX Applicability: All UH1 Series, and UH1 derivatives with the USA FAA Type Certificate Data sheets (TCDS) listed in the Requirement document. Requirement: Action in accordance with the technical requirements of FAA AD 99-25-12 Amdt 39-11455. Note: Replacement of the vertical fin spar in accordance with the Requirement document constitutes terminating action for the requirements of this Directive. Compliance: As specified in the Requirement document with a revised effective date of 20 November 2000. This Amendment becomes effective on 20 November 2000. Background: Following accident investigations, the FAA determined that a large number of high power events can cause fatigue cracking which will result in failure of the vertical fin spar, which in turn will result in loss of control of the helicopter. Amendment 1 was raised following an administrative error, and superseded AD/UH1/3 which was cancelled. Amendment 2 is issued in response to a superseding FAA AD which requires the same modification and inspections as the previous AD, and additionally, a further two inspections and replacement of the vertical fin spar. This further FAA action was prompted by reports of six accidents, two of which involved fatalities, and involved fatigue cracks in the vertical fin spar that have occurred since the issue of AD 97-20-09. COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Amendment 1 of this Directive became effective on 24 February 2000. The initial issue of this Directive became effective on 31 December 1999. David Alan Villiers Delegate of the Civil Aviation Safety Authority 17 November 2000 The above AD is notified in the Commonwealth of Australia Gazette on 20 November 2000.