AD/B737/352 Air Conditioning Outlet Extrusion Support Brackets (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 737 Series Aeroplanes

AD/B737/352 Air Conditioning Outlet
Extrusion Support Brackets 4/2009 DM

Applicability:	Model 737-600, -700, -700C, -800, and -900 series aircraft; as identified in Boeing Special Attention Service Bulletin 737-25-1544 Revision 1, or later FAA approved revision.
Requirement:	Action in accordance with the technical requirements of FAA AD 2009-01-02 Amdt 39-15780.
Compliance:	As specified in the Requirement document, with a revised effective date of 12 March 2009.
This Airworthiness Directive becomes effective on 12 March 2009.
Background:	The FAA received numerous reports of multiple cracks in the frames between BS 360 and BS 907 around the attachment holes of certain support brackets of the air conditioning outlet extrusions.  Undetected frame cracking could lead to a severed frame that, combined with cracking of the skin lap splice above stringer 10, could result in rapid decompression of the aircraft.

David Punshon
Delegate of the Civil Aviation Safety Authority

3 February 2009