AD/B747/347 Horizontal Stabilizer Drive Mechanism (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 747 Series Aeroplanes

AD/B747/347 Horizontal Stabilizer Drive Mechanism 8/2006

Applicability:

Boeing Model 747-100, 747-100B, 747- 100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series aeroplanes.

Requirement:

Action in accordance with FAA AD 2006-10-02 with a revised effective date of
3 August 2006.

Note:  FAA AD 2006-10-02 Amdt 39-14586 dated 28 April 2006 refers.

Compliance:

As detailed in FAA AD 2006-10-02.

This Airworthiness Directive becomes effective on 3 August 2006.

Background:

This AD results from a report of extensive corrosion of a ballscrew in the drive mechanism of the horizontal stabilizer on a similar aeroplane model.  The actions detailed in this AD are intended to prevent an undetected failure of the primary load path for the ballscrew in the horizontal stabilizer and subsequent wear and failure of the secondary load path, which could lead to loss of control of the horizontal stabilizer and consequent loss of control of the aeroplane.

James Coyne
Delegate of the Civil Aviation Safety Authority

20 June 2006