{"id":"F2006B03198","name":"AD/B747/305 - Wire Bundle W4489","slug":"ad-b747-305-wire-bundle-w4489","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42570,"registerId":"commonwealth-F2006B03198-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)  \n\nFor 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.\n\n![](image.001.png)  \n\nBoeing 747 Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/B747/305 Wire Bundle W4489 6/2004","sectionType":"part","heading":"AD/B747/305 Wire Bundle W4489 6/2004","content":"# AD/B747/305 Wire Bundle W4489 6/2004\n\nApplicability: Model 747-400 and \\-400D series aeroplanes, as listed in Boeing Alert Service Bulletin (ASB) 747-21A2427 dated 24 April 2003.\n\nRequirement: 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.\n\nNote: FAA AD 2004-07-20 Amdt 39-13564 refers.\n\nCompliance: Within 12 months after the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 10 June 2004.\n\nBackground: 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.\n\nIn 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.\n\n![Signature of James Coyne, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nJames Coyne\n\n![](image.001.png)Delegate of the Civil Aviation Safety Authority 27 April 2004","sortOrder":1}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":true,"description":"The AD makes mandatory inspection and corrective action for a rerouting fix the manufacturer implemented in 1990 where that fix may not have been applied. It targets specific 747-400/-400D aeroplanes listed in the Boeing ASB and requires retrospective verification and correction where needed, rather than introducing a new design change (Background; Applicability; Requirement)."},"complexity_factors":["Narrow technical focus: single wire bundle and localised area (Requirement).","Dependency on an external Boeing Alert Service Bulletin for inspection and corrective steps (Requirement).","Need to verify historical maintenance records to determine whether the 1990 reroute was performed (Background).","Variable repair scope: extent of wire or insulation damage determines labour and parts required (Requirement).","Fixed compliance period (12 months) imposes operational scheduling and potential downtime (Compliance).","Regulatory enforcement by CASA delegate provides limited administrative discretion over timing and applicability (preamble/signature)."],"plain_english_summary":"This Directive requires operators of Boeing 747-400 and -400D aeroplanes to inspect wire bundle W4489 near the chiller boost fan, repair any damage, and reroute the bundle where it could interfere with structure or components, in accordance with Boeing ASB 747-21A2427 (Applicability; Requirement). CASA's delegate sets a 12‑month compliance deadline; operators pay for inspections and repairs and must verify whether the manufacturer's 1990 rerouting was applied to their aircraft (Background; Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with a narrow, specific safety purpose. It addresses a known wiring defect in specific aircraft models and requires a targeted inspection/repair. The scope remains tightly focused on the original safety issue (fire risk from wire bundle W4489) without expansion into broader regulatory areas."},"complexity_factors":["Single specific technical requirement (inspect and reroute one wire bundle)","Only one applicability criterion (specific Boeing models listed in a service bulletin)","Simple compliance deadline (12 months from effective date)","No nested exceptions or conditional logic","Only 4 defined/document references (ASB 747-21A2427, FAA AD 2004-07-20, CASR 1998 subregulation 39.1(1))","Short document (approximately 300 words)"],"plain_english_summary":"This safety order requires operators of Boeing 747-400 and 747-400D passenger aircraft to inspect and, if needed, re‑route an incorrectly installed wire bundle (W4489) near the cargo bay cooling fan to stop chafing that can cause sparks and fires. Affected airlines and maintenance organisations must comply by June 2005 to prevent cargo‑hold electrical fires, following a similar FAA action after an actual fire."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-305-wire-bundle-w4489","history":"/api/acts/ad-b747-305-wire-bundle-w4489/history","analysis":"/api/acts/ad-b747-305-wire-bundle-w4489/analysis","conflicts":"/api/acts/ad-b747-305-wire-bundle-w4489/conflicts","importantCases":"/api/acts/ad-b747-305-wire-bundle-w4489/important-cases","documents":"/api/acts/ad-b747-305-wire-bundle-w4489/documents"}}