AD/B747/281 Amdt 1 Upper Deck Floor Beam Upper Chord and Web (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/B747/281 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/B747/281 Amdt 1 Upper Deck Floor Beam Upper Chord and Web 7/2005

Applicability:

Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747SP, and 747SR series aircraft, line numbers 1 through 810; and not equipped with a nose cargo door.

Requirement:

Action in accordance with the technical requirements of FAA AD 2005-06-12 Amdt 39-14020.

Note:  Boeing Alert Service Bulletins 747-53A2459 original issue, 747-53A2459 Revision 1, or a later FAA approved revision, refer.

Compliance:

As specified in the Requirement document, with a revised effective date of 7 July 2005.

This Amendment becomes effective on 7 July 2005.

Background:

The manufacturer received several reports of cracked upper deck floor beam upper chords on two aircraft.  The upper deck floor beams connect to the body frames in the flat sided area of the upper body, and cracking in the floor beams could extend and sever floor beams adjacent to the body frame and result in rapid decompression of the aircraft.

Amendment 1 is issued in response to a new FAA AD, which expands the existing inspection area and requires inspecting fastener holes in certain areas of aircraft modified previously, and taking corrective action if necessary.  The AD was prompted by reports of fatigue cracking of the upper chord of certain upper deck floor beams.

David Villiers
Delegate of the Civil Aviation Safety Authority

26 May 2005