COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Bell UH-1 Series Helicopters AD/UH-1/4 Tail Rotor Yoke 6/99 DM Applicability: Bell Helicopter Textron, Inc.-manufactured Model, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P helicopters. Requirement: Action in accordance with the technical requirements of FAA AD 99-07-15 Amdt 39- 11101. Accomplish the following in lieu of FAA AD 99-07-15 Paragraph (f), within the time stated in Paragraph (f): Revise the Operating Procedures and Manoeuvres Section of the Aircraft Flight Manual (AFM) to include the following additional procedures: TAIL ROTOR YOKE - PREFLIGHT VISUAL CHECK FOR STATIC STOP CONTACT DAMAGE (DEFORMED STATIC STOP OR TRUNNION YEILD INDICATOR). Note 1: Operators who use aircraft that have any of these affected yokes assemblies installed should use tail rotor tie downs when the aircraft is parked or stored. This task may be performed by inserting a copy of this applicable Directive into the Operating and Procedures Section of the AFM. Note 2: The Requirement document was forwarded with the Direct Mail copy of this Directive. Compliance: As specified in the Requirement Document for the initial and repetitive inspection requirements; with a revised effective date of 5 May 1999. This Airworthiness Directive becomes effective on 5 May 1999. Background: The FAA issued the Requirement Document in response to in-flight failures of yokes installed on civilian and military helicopters of similar type design, including three reported accidents. The actions specified by this Directive are intended to detect static or dynamic overload on the yoke due to external bending forces, which could result in failure of the yoke, loss of the tail rotor, and subsequent loss of control of the helicopter.