COMMONWEALTH OF AUSTRALIA (Civil Aviation Safety Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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 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/B747/305 Wire Bundle W4489 6/2004

Applicability: Model 747-400 and -400D series aeroplanes, as listed in Boeing Alert Service Bulletin (ASB) 747-21A2427 dated 24 April 2003.

Requirement: Inspect wire bundle W4489 in the area of the chiller boost fan in accordance with ASB 747-21A2427 for damage and current routing configuration. Repair any wire damage and reroute the wire bundle as required to remove possible interference between the wire bundle and the aircraft structure or components.

Note: FAA AD 2004-07-20 Amdt 39-13564 refers.

Compliance: Within 12 months after the effective date of this Directive.

This Airworthiness Directive becomes effective on 10 June 2004.

Background: The United States Federal Aviation Administration (FAA) received a report of a fire in the cargo bay left sidewall at station 900 on a Boeing Model 747-400 series aeroplane. The fire was caused by arcing between wire bundle W4489 and the receptacle housing of the chiller boost fan, which also caused fire damage to the surrounding insulation blankets and cargo liner.

In 1990, the manufacturer corrected this condition by rerouting wire bundle W4489 in the area of the chiller boost fan. However, the corrective action may not have been properly applied to certain Model 747-400 and -400D series aeroplanes delivered prior to and after 1990. The incorrect wire routing configuration could lead to possible interference between wire bundle W4489 and the receptacle housing of the chiller boost fan, drain tubes, and adjacent structure. This condition, if not corrected, could result in damage to the wire bundle and consequent arcing and fire.

James Coyne

Delegate of the Civil Aviation Safety Authority 27 April 2004

The above AD is notified in the Commonwealth of Australia Gazette on 19 May 2004.

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