AD/B737/110 Amdt 2 Rudder Yaw Damper Valve Replacement (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/B737/110 Amdt 1 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/B737/110 Amdt 2 Rudder Yaw Damper Valve Replacement 10/2005

Applicability:

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

Requirement:

1.    Unless already accomplished, perform a one time inspection of the engage solenoid valve of the yaw damper to determine the Part Number (P/N) of the valve.

2.    If any valve having one of the following part numbers is installed;

Parker P/N 59600-5011 (Boeing P/N 10-60811-9); or

Parker P/N 59600-5007 (Boeing P/N 10-60811-3 (see Note 3)); or

Parker P/N 59600-5003 (Boeing P/N 10-60811-1).

replace it with one of the following valves;

Parker P/N 881600-1001 (Boeing P/N 1060811-13), or

Sterer P/N 45080-1 (Boeing P/N 10-60811-8), or

Sterer P/N 45080 (Boeing P/N 10-60811-3 (see Note 3).

The above actions are to be accomplished in accordance with procedures specified in Chapter 22-11-61 or Chapter 22-12-21 (for 737 -100 and -200 series aircraft) of the Boeing Maintenance Manual as applicable; or Chapter 22-12-21 (for 737-300, -400, and -500 series aircraft) of the Boeing Maintenance Manual.

Accomplishment of the requirements of AD/B737/201 (FAA AD 2002-20-07) constitutes terminating action for the requirements of this Directive.

Note 1.  FAA AD 97-09-15 R1 Amdt 39-10912 refers.

Note 2.  Boeing In-Service Activities Report 95-03-2725-10 dated 16 February 1995 (for model 737-100 and -200 series aircraft), or 95-04-2725-10, dated 24 February 1995 (for Model 737-300, -400 and -500 series aircraft) provide additional information concerning interchangeability of solenoid valve part numbers.

Note 3.  Operators should note that, as identified above, two Parker and Sterer Part Numbers have the same Boeing Part Number (10-60811-3).  If, upon inspection, Boeing Part number 10-60811-3 is found to be installed, operators must ascertain the vendor part number.  Parts with Boeing P/N 10-60811-3 and Parker P/N 59600-5007 must be replaced and are not considered to be acceptable replacement parts.  In addition, some engage solenoid valves may be labelled with only the name “Bertea”, rather than “Parker” or “Parker-Bertea”.

Compliance:

1.    Within 5 years or 15,000 flights after 25 February 1999 or at the next time the PCU is removed for maintenance, whichever is the earlier.

2.    Before further flight.

The compliance times remain unchanged by this issue.

This Amendment becomes effective on 29 September 2005.

Background:

Investigation into the Boeing 737 flight control system has revealed system anomalies, which, if not corrected, could lead to reduced controllability or uncommanded control input.  This Directive was issued as a direct result of these investigations to remove a potential source of failure within the yaw system.

Amendment 1 clarified component identification and reflected the requirements of the Country of Origin Aviation Authority.

Amendment 2 is issued in response to FAA AD 2002-20-07, which requires incorporation of a new rudder control system; which when incorporated, supersedes the requirements of AD 97-09-15 R1, the Requirement document of this Directive.

The original issue of this Airworthiness Directive became effective on 17 July 1997.

David Punshon
Delegate of the Civil Aviation Safety Authority

19 August 2005