AD/B737/229 Amdt 1 Lavatory Drain System (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/B737/229 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/B737/229 Amdt 1 Lavatory Drain System 4/2006

Applicability:

Boeing Model 737 -100, -200, -300, -400 and -500 series aeroplanes.

Requirement:

Action in accordance with the instructions as detailed in FAA AD 2004-06-18.

Note 1:  FAA AD 2004-06-18 Amdt 39-13544 refers which supersedes FAA AD
89-11-03 Amdt 39-6223.

Note 2:  This Directive supersedes AD/B737/25 Amdt 1.

Compliance:

As detailed in the compliance section of FAA AD 2004-06-18 with a revised effective date of 13 April 2006.

This Amendment becomes effective on 13 April 2006.

Background:

The requirement to carry out certain checks of the lavatory drain system was originally detailed in AD/B737/25; however the content of those requirements has changed significantly.  Subsequently this Directive has been issued to reflect those requirements.  The requirements previously detailed are no longer considered satisfactory to prevent the build up of “blue ice” and the problems associated with the dislodgment of the “blue ice” from the aeroplane.

This Directive requires in addition to the existing leak checks, periodic replacement of the seals, replacement of “donut valves” with other valves and a revision to the leak check interval.

This Amendment changes the title by removing “Forward” from the title of the AD with no change to the technical content.  This is to reduce confusion as to which lavatory drain systems are affected.

The original issue of this AD became effective on 28 October 2004.

Jayaprakashan Ambali
Delegate of the Civil Aviation Safety Authority

21 February 2006