AD/B747/336 Nacelle Strut Attach Pin/Bolt, Dual Side Brace, and Underwing Midspar Fitting (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(1) of CASR 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 or aeronautical product 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.

Boeing 747 Series Aeroplanes

AD/B747/336 Nacelle Strut Attach Pin/Bolt, Dual Side
Brace, and Underwing Midspar Fitting 12/2005

Applicability:	Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, -400, -400D, -400F, 747SR, and 747SP series aircraft; as identified in Boeing Service Bulletin 747-54A2218 Revision 1, dated 24 February 2005, or later FAA approved revision.
Requirement:	Action in accordance with the technical requirements of FAA AD 2005-19-09 Amdt 39-14274.
Compliance:	As specified in the Requirement document, with a revised effective date of 24 November 2005.
This Airworthiness Directive becomes effective on 24 November 2005.
Background:	The FAA received reports of corroded, migrated, and rotated bearings for the dual side braces in the inboard and outboard engine mounting struts, a report of a fractured retainer for the eccentric bushing for one of the side links of a dual side brace, and reports of wear and damage to the underwing midspar fitting on the outboard strut.  The actions required by this Directive are intended to prevent the loss of a dual side brace or underwing midspar fitting load path, which could result in the transfer of loads and motion to other areas of a strut, and possible separation of a strut and engine from the aircraft during flight.

David Villiers
Delegate of the Civil Aviation Safety Authority

12 October 2005