AD/B747/62 Amdt 3 Flap Carriage Spindles and Aft Link Assembly (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B747/62 Amdt 2 and issues the following 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/B747/62 Amdt 3 Flap Carriage Spindles and Aft Link Assembly 1/2009

Applicability:

Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, -400, -400D, -400F, and 747SR series aircraft.

Requirement:

Action in accordance with the technical requirements of FAA AD 2008-22-17 Amdt 39-15714.

Compliance:

As specified in the Requirement document, with a revised effective date of
15 January 2009.

This Amendment becomes effective on 15 January 2009.

Background:

In an overseas incident, undetected stress corrosion caused failure of two spindles on one flap which resulted in severe handling difficulties.  Fractured flap carriage aft links have also been detected overseas.

Amendment 1 referenced Revision 2 of the Requirement document which requires inspection and overhaul of aft link assemblies, additional inspections, revised compliance intervals and requirement to overhaul or replace spindles.

Amendment 2 required additional work, i.e. internal inspection of the spindles.  It also referenced the superseding FAA AD as the Requirement document due to the requirement and compliance diverging from Boeing Service Bulletin 747-27-2280 Revision 3.

Amendment 3 is issued in response to a new FAA AD, which adds a repetitive inspection to detect broken parts, and revises the overhaul threshold and repetitive intervals.  The FAA AD results from analysis that showed additional inspections should be done to prevent the loss of a flap, and that the flight-hour-based interval should be revised to a flight-cycle-based interval, because the greatest loads on the spindles happen during takeoff and landing.

David Villiers
Delegate of the Civil Aviation Safety Authority

27 November 2008