AD/B737/256 Hydraulic System "B" Abex Pump Motor (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/B737/256 Hydraulic System "B" Abex Pump Motor 13/2005

Applicability:

Boeing Models 737-100, and 737-200 series aeroplanes, equipped with hydraulic system "B" Abex P/N 57186 pump motor.

Requirement:

1.    Install the ground fault protection systems in the hydraulic system "B" Abex pump motor electric power circuits in accordance with Boeing Service Bulletin 737-29-1029 Revision 2, dated 8 October 1976 or later FAA-approved revisions; or

2.    Install the hydraulic "B" system motor driven pumps, either new or upgraded, in accordance with Boeing Service Bulletin 737-29-1036, dated 30 April 1980, or later FAA-approved revisions.

Note:  FAA AD 87-02-05R1 Amdt 39-5675 refers.

Compliance:

Within 30 days after the effective date of this AD, unless previously accomplished.

This Airworthiness Directive becomes effective on 22 December 2005.

Background:

This AD is intended to prevent a hydraulic system "B" Abex P/N 57186 pump motor internal wiring fault from burning a hole in the pump motor case and providing an ignition source to any flammable liquids.

James Coyne
Delegate of the Civil Aviation Safety Authority

10 November 2005