AD/B747/299 Amdt 1 Yaw Damper Actuator (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/B747/299 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 747 Series Aeroplanes

AD/B747/299 Amdt 1 Yaw Damper Actuator 11/2006

Applicability:

Model 747-400, -400D, and -400F series aircraft, as listed in Boeing Service Bulletin 747-27A2397 Revision 2, dated 21 September 2005.

Requirement:

Action in accordance with the technical requirements of FAA AD 2006-18-17
Amdt 39-14756.

Compliance:

As specified in the Requirement document, with a revised effective date of
26 October 2006.

This Amendment becomes effective on 26 October 2006.

Background:

The original issue of this Airworthiness Directive required an ultrasonic inspection of the yaw damper portion of the upper and lower rudder power control modules main manifold for cracking.  Such cracking, unless detected and corrected, could result in an uncommanded left rudder hardover, consequent increased pilot workload, and possible runway departure upon landing.

This amendment expands the applicability and discontinues certain requirements of the previous Airworthiness Directive.

The original issue of this Airworthiness Directive became effective on
22 January 2004.

David Villiers
Delegate of the Civil Aviation Safety Authority

14 September 2006