COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 747 Series Aeroplanes 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 39.1 (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. AD/B747/237 Thrust Reverser Auxiliary Track Assembly 12/2000 Applicability: Boeing 747-400 series aircraft powered by Pratt and Whitney PW4000 engines, line numbers 696 through 1100 inclusive. Requirement: 1. Carry out initial and repetitive inspections of the thrust reverser auxiliary beam assemblies in accordance with the technical instructions in FAA AD 2000-11-28, Paragraph (a). Repair or replace discrepant parts prior to further flight. 2. Incorporate improved liner and slider assemblies in accordance with the technical instructions in FAA AD 2000-11-28, either Paragraph (b) or (c), as applicable. Compliance with Requirement 2 of this Directive constitutes terminating action for the inspections specified in Requirement 1 for each modified beam assembly. Note: Boeing Alert Service Bulletin 747-78A2164, Revision 2 refers. Compliance: 1. As detailed in the Requirement document with the effective date revised to 30 November 2000. 2. No later than the respective period specified in the Requirement document. This Airworthiness Directive becomes effective on 30 November 2000. Background: Excessive wear in the thrust reverser auxiliary track beam assemblies can lead to disengagement of a slider and separation of a portion of the thrust reverser. Liberation of thrust reverser parts could damage the aircraft structure or pose a hazard to persons on the ground. Eugene Paul Holzapfel Delegate of the Civil Aviation Safety Authority 24 October 2000 The above AD is notified in the Commonwealth of Australia Gazette on 1 November 2000.