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/B737/250 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 737 Series Aeroplanes
AD/B737/250 Amdt 3
Forward Entry Door Forward
and Aft Side Intercostals
4/2010
 
Applicability:
Model 737-100, -200, -200C, -300, -400, and -500 series aircraft; as identified in Boeing Special Attention Service Bulletin 737-53A1204 Revision 1, or later FAA approved revision.

Requirement:
Action in accordance with the technical requirements of FAA AD 2009-16-14 Amdt 39-15987.
Corrective actions (repairs and/or repeat inspections) that are approved on an FAA form 8100-9 and acceptable as an Alternative Method of Compliance (AMOC) to FAA AD 2009-16-14, may be carried out without the need to obtain an exclusion from CASA from this Airworthiness Directive.
Corrective actions (repairs and/or repeat inspections) that were approved on FAA form 8100-9 and acceptable as an Alternative Method of Compliance (AMOC) to superseded FAA AD 2005-20-03, are approved for the corresponding provisions of this Directive, provided the repetitive inspection intervals (if any) do not exceed 6,000 flight cycles.  Such corrective actions may be carried out without the need to obtain an exclusion from CASA from this Airworthiness Directive.

Compliance:
As specified in the Requirement document, with a revised effective date of
24 September 2009.

 
This Amendment becomes effective on 2 March 2010.

Background:
The FAA received reports of fatigue cracks on several Model 737-200 series aircraft.  The actions required by this Directive are intended to detect and correct fatigue cracking of the intercostals on the forward and aft sides of the forward entry door, which could result in loss of the forward entry door and rapid depressurisation of the aircraft.
Amendment 1 allowed the automatic acceptance of repair schemes, without the need for an exclusion application to be forwarded to CASA, provided that the repair scheme was approved as an AMOC to FAA AD 2005-20-03 paragraphs (l) and (m) and accompanied by FAA form 8100-9.

 
 
 
Amendment 2 was prompted by additional reports of fatigue cracks.  The new FAA AD reduces the repetitive inspection intervals, and expands the inspection area for Model 737-200C series aircraft to include the area aft of the forward entry door.
Amendment 3 is issued to allow automatic acceptance of repairs and/or repeat inspections that are approved by the FAA as an Alternative Method of Compliance to FAA AD 2009-16-14, without the need to obtain an exclusion from CASA.

Mike Higgins
Delegate of the Civil Aviation Safety Authority
25 February 2010