AD/B737/307 Amdt 2 Main Slat Track Downstop 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/B737/307 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 737 Series Aeroplanes

AD/B737/307 Amdt 2 Main Slat Track Downstop Assembly 10/2010

Applicability:

All Model 737-600, -700, -700C, -800, -900, and -900ER series aircraft.

Requirement:

Action in accordance with the technical requirements of FAA Emergency AD
2007-18-52.

Corrective actions (repairs) that are on an FAA form 8100-9 and approved by the Manager, Seattle Aircraft Certification Office or an Authorised representative, as defined in paragraph (h)(3) of FAA AD 2007-18-52, as an Alternative Method of Compliance (AMOC) to the requirements of FAA AD 2007-18-52 Amdt 39-15197, may be carried out without the need to obtain an exclusion from CASA from this airworthiness directive.

Compliance:

The compliance time remains unchanged which was as specified in the Requirement document.

This Amendment becomes effective on 21 May 2010.

Background:

The FAA received reports of parts of the main slat track downstop assembly coming off the main slat track.  In one case, a nut fell into the slat track housing and, during a subsequent slat retraction, the track made contact with the nut, pushing it into the wall of the housing and puncturing it.  In a recent case, an initial investigation revealed that following retraction of the slats after landing on a Model 737-800 aircraft, loose parts of the main slat track downstop assembly punctured the slat track housing, which resulted in fuel leakage and a fire that ultimately destroyed the aircraft.

Amendment 2 allows the use of FAA approved AMOCs without the need to obtain an exclusion from CASA.

Amendment 1 was issued in response to a new FAA Emergency AD, which was prompted by additional reports of parts coming off the main slat track downstop assemblies.  In these cases, the parts were found in the bottom of the slat track housing.  Additionally, in one case, the slat track housing was damaged.  Based on this new information, the FAA determined that the original compliance time was not adequate to address the unsafe condition, and the compliance time has been adjusted accordingly.

Mike Higgins
Delegate of the Civil Aviation Safety Authority

13 May 2010