AD/B737/232 - Horizontal Stabiliser Pivot Hinge Pins (Cth)

COMMONWEALTH OF AUSTRALIA (Civil Aviation Safety Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES

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 39.1 (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/B737/232 Horizontal Stabiliser Pivot Hinge Pins 12/2004

Applicability: Model 737-100, -200, -200C, -300, -400, and -500 series aircraft, line numbers 1 through 3132.

Requirement: Action in accordance with the technical requirements of FAA AD 2004-19-10 Amdt 39-13804.

Note: Boeing Alert Service Bulletin 737-55A1077 original issue, or later FAA approved revision, refers.

Compliance: As specified in the Requirement document, with a revised effective date of 25 November 2004.

This Airworthiness Directive becomes effective on 25 November 2004.

Background: Reports have been received of corrosion in the pivot hinge pins that attach the horizontal stabiliser centre section to the Body Station 1156 support bulkhead. The degree of corrosion found on outer primary pins, and inner fail-safe pins made from both 4330steel and 15-5 PH corrosion resistant steel, could increase the likelihood of stress corrosion cracking. An undetected failure of the outer primary pin and the inner fail-safe pin could enable the pins to migrate out of the stabiliser hinge joint and result in intermittent movement of the horizontal stabiliser structure, and consequent loss of controllability of the aircraft.