Document ID: chunk:federal_register_of_legislation:F2006B04691:body:0:p2
Version: federal_register_of_legislation:F2006B04691
Segment Type: other
Provision Reference: 
Character Range: 2963–5962

Series: Mandatory Retirement Bell Maintenance and Overhaul Instructions dated 1 March 1964 incorporating Revision No. 7 dated 15 July 1981.

11.    For all models, replace P/N 47-642-102 tail rotor blades with improved blades P/N 47-642-117 prior to 1 July 1981.

12.    For aircraft fitted with Texas Helicopter Corporation modified control system in accordance with US FAA STC SH2772SW, the retirement life for the weld assembly P/N 74-150-117-13M shall be 5000 hours.

13.    For aircraft re-engined in accordance with US FAA STC SH657NW (held by Siam Hiller Holdings, Inc.), the retirement lives of the Adapter plate (P/N Soloy 660-2101), Drive shaft (P/N Soloy 660-2408) and Engine Mount (P/N Bell 47- 612-171-123) shall be as specified in US FAA STC SH657NW as amended 30 June 1999.

14.    Retire tail rotor yokes P/N 74-641-057-9 from service before 1 January 1987.

            Note: Operators of aircraft engaged in operations which involve unusual manoeuvres, such as agricultural, or cattle mustering or operations where consistently more than four rotor full stop flights per hour are achieved must consult the manufacturer giving full details including previous history of all operations for possible life revision and must advise the Authority accordingly. For the purposes of notification two flights concluding with the rotors turning while on the ground and the engine at idle or greater power setting shall be counted as equivalent to one flight to rotor full stop.

 Compliance: As specified in the Requirement references and text.

            This Amendment becomes effective on 3 December 2003.

            Background: This amendment is issued to amend requirement13 to reflect the retirement lives as listed in FAA STC number SH657NW.

            Amendment 19, effective 9 April 1987, incorporated the effect of AD/BELL 47/93 which was cancelled.

            Amendment 20 effective on 9 April 1987, cancelled all of the retirement life data previously specified in the various models' Maintenance and Overhaul Instructions and consolidated all current Airworthiness Life Limitations into the one document.

            Amendment 21, effective 11 August 2000, was issued as a result of information received from Bell Helicopter Textron by Information Letter 47-00-6 which advised that several errors had been discovered concerning the component retirement lives published in Alert Service Bulletin (ASB) 47-00-24 (the Requirement document of AD/BELL 47/61 Amdt 20), as well as authorised installation of certain components on specific 47 series helicopters. The content of AD/BELL 47/61 Amdt 19 has been reinstated until such time as a revised copy of ASB 47-00-24 is received, whereupon this Directive will be amended. As of the date of effect of Amendment 22 of this AD, service bulletin ASB 47-00-24 had not been revised. The requirements and compliance of this amendment are unchanged from Amendment 21, except for the inclusion of the Kawasaki 47G3B-KH4 model in part