AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B747/250 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 747 Series Aeroplanes AD/B747/250 Amdt 1 Thrust Reverser 9/2002 Applicability: Boeing Model 747-400 series aeroplanes equipped with Pratt and Whitney PW4000 series engines. Requirement: 1. a. Install an additional locking system on each engine thrust reverser in accordance with the instructions detailed in Boeing Service Bulletin (SB) 747-78-2155, Revision 2, dated 5 November 1998. b. Modify the central maintenance computer system hardware and software in accordance with Boeing SB 747-45-2016, Revision 1, dated 2 May 1996. c. Modify the integrated display system software in accordance with Boeing SB 747-31-2245, dated 27 June, 1996. d. Install the provisional wiring for the locking system on the thrust reverser in accordance with Boeing SB 747-78-2154, Revision 3, dated 11 December 1997. 2. Carry out a function test to detect discrepancies of the additional locking system on each engine thrust reverser, in accordance with Appendix 1 of FAA AD 2000- 12-21 Amendment 39-11799. 3. Correct any discrepancies detected while carrying out Requirement 2 or 4 function test in accordance with approved maintenance data. 4. Repeat Requirement 2 functional test. Terminating Action Installation of the additional locking systems accomplished prior to the effective date of this Directive in accordance with Boeing SB 747-78-2155, Revision 1. dated 30 January 1997, satisfy the requirements of Requirement 1(a). Installation of the additional locking systems accomplished prior to the effective date of this Directive in accordance with Boeing SB 747-78-2154, Revision 1. dated 2 November 1995 and Revision 2, dated 31 October 1996, satisfy the requirements of Requirement 1(d). Boeing 747 Series Aeroplanes AD/B747/250 Amdt 1 (continued) For aeroplanes having line numbers 1067 and higher on which the intent of Boeing SB 747-78- 2155, Revision 2. dated 5 November, 1998, was accomplished during production, accomplishment of the repetitive functional tests required by Requirement 4 of this Directive is terminating action for the repetitive inspections and functional tests required by Requirement 1 of AD/B747/277. Accomplishment of the requirements of this Directive is also terminating action for the repetitive inspections and functional tests required by Requirement 1 of AD/B747/277. Note: FAA AD 2001-12-21 Amendment 39-11799, and 94-15-05 Amendment 39-8976 refer. Compliance: For Requirement 1: Prior to issue of Certificate of Airworthiness. For Requirement 2: Prior to issue of Certificate of Airworthiness. For Requirement 3: Prior to further flight. For Requirement 4: At intervals not exceeding 4000 hours time- in-service. This Amendment becomes effective on 5 September 2002. Background: This amendment includes a number of editorial and technical changes to better represent the requirements of FAA AD 2000-12-21. This Directive was issued to prevent inadvertent deployment of the thrust reverser during flight and consequent reduced controllability of the aeroplane. The original issue of this Airworthiness Directive became effective on 9 August 2001. Eugene Paul Holzapfel Delegate of the Civil Aviation Safety Authority 25 July 2002 The above AD is notified in the Commonwealth of Australia Gazette on 14 August 2002.