AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B737/109 Amdt 1 and issues the following AD under subregulation 39.1 (1) of CAR 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/B737/109 Amdt 2 Flying Control Power Control Unit Cylinder Bore Replacement 11/2002 TX Applicability: Model 737-100, -200, -300, -400, and -500 series aeroplanes, having a main rudder power control unit (PCU) part number P/N 65-44861-( ), P/N 65C37052- ( ) or P/N 65C37053-( ), except those having a serial number of 1252A or greater or having a serial number that contains "ss", or an aileron or elevator PCU having P/N 65-44761-( ), except those having a serial number of 5360A or greater or having a serial number that contains "ss". Requirement: 1. Perform an inspection of the applicable PCU to determine if repaired or reworked PCU manifold cylinder bores containing chrome plating are installed, in accordance with Boeing Service Letter 737-SL-27-30 dated April 1, 1985. 2. Any PCUs identified with chrome plated manifold cylinder bores are to have the bores replaced in accordance with Boeing Service Letter 737-SL-27-30 dated April 1, 1985. Note 1: FAA AD 2000-02-18 Amendment 39-11536 refers and supersedes FAA AD 97-09-14 Amendment 39-10010. Compliance: 1. Within 5 years or 15,000 flight hours time in service, whichever occurs first, after 14 August 1997 for P/N 65-44761-( ) and 65-44861-( ) components as identified by serial numbers in applicability section. Within 5 years or 15,000 flight hours time in service, which ever occurs first after 13 July 2000, for P/N 65C37052-( ) and P/N 65C37053-( ) components as identified by serial numbers in the applicability section. Note 2: Any PCU that has been vibroengraved with "737-SL-27-30" has previously been inspected in accordance with Boeing SL 737-SL-27-120 for chrome plating. 2. Before further flight. This Amendment becomes effective on 28 August 2002. Background: Investigation into the Boeing 737 flight control system revealed system anomalies, which, if not corrected, could lead to reduced controllability or uncommanded control input. This directive is issued as a direct result of these investigations, with compliance times as developed by the FAA. Boeing 737 Series Aeroplanes AD/B737/109 Amdt 2 (continued) Amendment 2 has been raised to correct an error in the Applicability section. Amendment 1 has been raised to add additional rudder PCU P/Ns to the inspection requirement. Amendment 1 of this Airworthiness Directive became effective on 13 July 2002 The original issue of this Airworthiness Directive became effective on 14 August 1997. James Coyne Delegate of the Civil Aviation Safety Authority 26 August 2002 The above AD is notified in the Commonwealth of Australia Gazette on 28 August 2002.