{"id":"F2005L00107","name":"AD/B747/119 Amdt 1 - Engine Bleed Air Crossover Duct","slug":"ad-b747-119-amdt-1-engine-bleed-air-crossover-duct","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":33515,"registerId":"commonwealth-F2005L00107-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Boeing 747 Series Aeroplanes","sectionType":"division","heading":"Boeing 747 Series Aeroplanes","content":"### Boeing 747 Series Aeroplanes\n\n| AD/B747/119 Amdt 1 | Engine Bleed Air Crossover Duct | 2/2005 |\n| ------------------ | ------------------------------- | ------ |\n\n| Applicability: | All model 747 aircraft, except model 747-400 series, line position 2 through 707.                                                                                                                                                                                                                         |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Action in accordance with Boeing Service Bulletin 747-36-2078 revision 2 or revision 3.Note: FAA AD 90-21-09 Amdt 39-6756 refers.                                                                                                                                                                         |\n| Compliance:    | Remains unchanged as detailed in the original issue of this Directive, as specified in the requirement document.                                                                                                                                                                                          |\n|                | This Amendment becomes effective on 17 February 2005.                                                                                                                                                                                                                                                     |\n| Background:    | The manufacturer has reported a number of failed crossover ducts which have resulted in damage to the aircraft or interruption to scheduled air services.This amendment corrects the service bulletin referenced in this Directive.The original issue of this Directive became effective on 24 June 1993. |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n13 December 2004\n\nThe above AD is notified in the Commonwealth of Australia Gazette on 26 January 2005.","sortOrder":0},{"sectionNumber":"AD/B747/119 Amdt 1","sectionType":"part","heading":"AD/B747/119 Amdt 1","content":"## AD/B747/119 Amdt 1","sortOrder":1},{"sectionNumber":"Engine Bleed Air Crossover Duct","sectionType":"part","heading":"Engine Bleed Air Crossover Duct","content":"## Engine Bleed Air Crossover Duct","sortOrder":2},{"sectionNumber":"2/2005","sectionType":"part","heading":"2/2005","content":"## 2/2005","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment corrects the reference to the applicable Boeing service bulletin and reconfirms the original compliance requirement. It does not materially broaden the AD's scope or introduce new categories of mandatory work beyond what the original 1993 Directive required."},"complexity_factors":["Short directive with a single substantive requirement (follow Boeing Service Bulletin 747-36-2078 rev 2 or rev 3)","One narrow applicability exception (excludes certain 747-400 series aircraft by line position), which may require cross-referencing operator records","Cross-reference to an external FAA AD (FAA AD 90-21-09), adding a minor jurisdictional cross-check","Reliance on an external document (the Boeing service bulletin) for technical detail rather than embedding procedures in the AD","No nested exceptions or multiple conditional branches within the AD text itself"],"plain_english_summary":"**What this directive does (mechanical change)\n\n- This is an Airworthiness Directive (AD) for Boeing 747 series aeroplanes that requires operators to carry out the work specified in Boeing Service Bulletin 747-36-2078 (either revision 2 or revision 3).  The work concerns the engine bleed air crossover duct — a duct that carries high-pressure bleed air between engine bleed systems.  The AD does not change the compliance requirements that were set out in the original 1993 Directive; it corrects the service‑bulletin reference and confirms the required action.\n\n**Which aeroplanes are affected\n\n- Applies to all model 747 aircraft except certain 747-400 series aeroplanes (the text excludes \"model 747-400 series, line position 2 through 707\").  Operators should check their aircraft serial/line position against that exclusion to determine applicability.\n\n**Why it was issued (stated purpose)\n\n- The manufacturer reported multiple failures of crossover ducts that caused aircraft damage and interruptions to scheduled services.  The stated aim of the AD is to address those failures by mandating the corrective work described in the Boeing service bulletin.  The amendment corrects which revision of the service bulletin is referenced.\n\n**How it works in practice\n\n- Operators must perform the inspection/repair/modification actions set out in Boeing Service Bulletin 747-36-2078 rev 2 or rev 3.  The AD cross‑references FAA AD 90-21-09 (Amdt 39-6756), so operators should note equivalent or overlapping requirements from the FAA if the aeroplane is operated internationally.  The amendment became effective 17 February 2005; the original AD first became effective 24 June 1993.\n\n**Who pays, who decides, and what changes behaviour\n\n- Who pays: aircraft owners/operators are responsible for carrying out the mandated work and for the direct costs (parts, labour, and any aircraft downtime).  If parts or service are supplied or subsidised by the manufacturer under warranty or commercial agreement, that is a separate contractual matter.\n- Who decides: the Civil Aviation Safety Authority (CASA) issued the AD; the mandated technical steps are those specified by Boeing in the referenced service bulletin.  In practice, operators or their maintenance organisations schedule and perform the work according to the bulletin and the AD.\n- Behaviour change required: operators must inspect and, where required, replace or modify the crossover duct per the service bulletin.  This imposes scheduled maintenance tasks and potential aircraft out-of-service time.\n\n**Costs, incentives and trade-offs (practical effects)\n\n- Direct costs: parts, labour, and aircraft downtime for the mandated inspections/repairs.  These are borne by the operator unless alternative commercial arrangements exist.\n- Avoided costs: the AD aims to reduce the risk of duct failure, which previously led to aircraft damage and service interruptions.  Preventing such failures can avoid larger repair bills and revenue loss from cancellations.\n- Implementation risk: the amendment corrects the referenced service bulletin, which reduces the risk of misapplication.  Practical risks remain: availability of parts, maintenance capacity, and scheduling disruptions.  Where the bulletin is ambiguous, maintenance organisations may need technical clarification from Boeing or CASA.\n- Regulatory interaction: the AD explicitly refers to a prior FAA AD. Operators that operate internationally should confirm they meet both CASA and FAA requirements where applicable.\n\n**Compliance burden and discretion\n\n- The AD requires compliance with a manufacturer service bulletin; it does not expand the range of discretionary choices available to operators beyond seeking technical clarification or, where permitted under the regulations, requesting an alternative method of compliance (not specified in the text of this AD).\n\n**Net scope effect compared to the original directive\n\n- The amendment does not change the underlying compliance obligations; it corrects the service‑bulletin reference and reconfirms the existing requirement to carry out the actions in Boeing Service Bulletin 747-36-2078.  It therefore keeps the original safety objective (prevent crossover duct failures) and does not broaden the categories of work required beyond what the original AD specified.\n\n(Operators should consult the full Boeing service bulletin and the original AD for detailed technical steps, compliance times, and any exceptions.)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a minor administrative amendment that corrects a document reference. The scope remains identical to the original 1993 directive — same aircraft, same safety issue, same compliance requirements."},"complexity_factors":["Very short document (under 300 words)","Only 1 substantive requirement referencing an external technical document","Single applicability exclusion (747-400 series, line positions 2-707)","No defined terms section","No nested conditional logic or exceptions","Cross-reference to only 1 external document (FAA AD 90-21-09) and 1 service bulletin"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of certain Boeing 747 aircraft to inspect or repair a specific part called the **engine bleed air crossover duct**.\n\n**What it does:**\n- Mandates that airlines follow specific instructions in Boeing Service Bulletin 747-36-2078 (revision 2 or 3) to address failures of the crossover duct — a component that carries hot compressed air between engines.\n\n**Who it affects:**\n- All Boeing 747 models **except** the 747-400 series built at line positions 2 through 707 (essentially early production 747-400s).\n\n**Why it matters:**\n- The manufacturer reported multiple failures of these ducts that caused aircraft damage and disrupted flights. This amendment updates which version of the repair instructions must be followed.\n\n**Key change in this amendment:**\n- Corrects the referenced service bulletin to specify revisions 2 or 3 (instead of an earlier incorrect reference).\n- The actual compliance deadline and required actions remain the same as the original 1993 directive."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-119-amdt-1-engine-bleed-air-crossover-duct","history":"/api/acts/ad-b747-119-amdt-1-engine-bleed-air-crossover-duct/history","analysis":"/api/acts/ad-b747-119-amdt-1-engine-bleed-air-crossover-duct/analysis","conflicts":"/api/acts/ad-b747-119-amdt-1-engine-bleed-air-crossover-duct/conflicts","importantCases":"/api/acts/ad-b747-119-amdt-1-engine-bleed-air-crossover-duct/important-cases","documents":"/api/acts/ad-b747-119-amdt-1-engine-bleed-air-crossover-duct/documents"}}