AD/B747/261 Amdt 2 Fuselage Station 800 Frame (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/B747/261 Amdt 1 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/B747/261 Amdt 2 Fuselage Station 800 Frame 10/2007

Applicability:

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

Requirement:

Action in accordance with the technical requirements of FAA AD 2007-16-08 Amdt 39-15147.

Note:  Boeing Alert Service Bulletins 747-53A2451, including Appendix A, and
747-53A2451 Revision 1, or later FAA approved revision, refer.

Compliance:

As specified in the Requirement document, with a revised effective date of
27 September 2007.

This Amendment becomes effective on 27 September 2007.

Background:

Reports were received from operators of cracks found in the strap and inner chord angle at station 800 frame.  Undetected fatigue cracks could extend and fully sever the frame, which could result in the development of skin cracks that could lead to rapid depressurisation of the aircraft.

Amendment 1 was prompted by several reports of cracks of the station 800 frame assembly on aircraft that had accumulated fewer total flight cycles than the initial inspection threshold in superseded FAA AD 2001-14-22.

Amendment 2 is issued in response to a new FAA AD, which revises certain applicabilities and compliance times of the previous FAA AD.

David Villiers
Delegate of the Civil Aviation Safety Authority

14 August 2007