{"id":"F2006B03045","name":"AD/B747/144 - Engine Thrust Control - Idler Cable Pulley Support Bracket","slug":"ad-b747-144-engine-thrust-control-idler-cable-pulley-support-bracket","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":42404,"registerId":"commonwealth-F2006B03045-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/B747/144 - Engine Thrust Control - Idler Cable Pulley Support Bracket","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nBoeing 747 Series Aeroplanes\n\nAD/B747/144 Engine Thrust Control - Idler Cable Pulley Support Bracket\n\n  \n5/95\n\nApplicability: B747 Line numbers 202 to 886 inclusive equipped with GE CF6-45/50 engines.\n\nRequirement: 1. Visually inspect number 1 strut engine thrust control cable idler pulley support bracket for cracking in accordance with Boeing SB 747-76A2083. Brackets with a single crack less than 2.0 inches long may remain in service provided the interim repair is installed in accordance with Boeing SB 747-76A2083 Revision 1.\n\n2. Replace the aluminium alloy idler pulley support bracket with one made of Inconel 625 in accordance with Boeing SB 747-76A2083 Revision 2.\n\nNote: FAA AD 93-17-06 refers.\n\nCompliance: 1. a. Inspect in accordance with Requirement 1 before 9000 hours time in service or within 600 hours time in service from 27 April 1995, whichever is the later.\n\nRe-inspect at intervals not to exceed 600 hours time in service.\n\n    b. Inspect brackets with the interim repair installed in accordance with Requirement 1 at intervals not to exceed 100 hours time in service.\n\n    2. a. Replace interim repaired brackets in accordance with Requirement 2 within 750 hours time in service from repair installation.\n\n2. b. Replace brackets in accordance with Requirement 2 before 10 November 1995.\n\nNote: Replacement with brackets manufactured from Inconel 625 cancels the inspection requirements of this AD.\n\nBackground: Five operators have reported cracks in the thrust control cable idler pulley support brackets. Failure of the brackets could result in loss of control of engine thrust.","sortOrder":0}],"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":5,"scope_assessment":{"changed":false,"description":"Scope remains targeted to the reported cracking problem for B747 line numbers 202–886 with GE CF6-45/50 engines. The instrument prescribes inspections, allows a limited interim repair condition, and mandates full replacement with Inconel 625 per Boeing SBs; replacement cancels inspections. There is no textual indication in the instrument that applicability or remedial scope was broadened beyond addressing the reported bracket failures (Applicability; Requirement 1–2; Note; Background)."},"complexity_factors":["Narrow applicability tied to specific airframe line numbers and engine type — \"Applicability: B747 Line numbers 202 to 886 inclusive equipped with GE CF6-45/50 engines.\"","Technical inspection threshold and interim allowance — single crack under 2.0 inches may remain with interim repair (Requirement 1).","Multiple, overlapping compliance timings: initial inspection deadline, recurring inspection intervals, shorter intervals when interim repair installed, and separate replacement deadlines (Compliance 1.a, 1.b, 2.a, 2.b).","Mandatory part-material change to Inconel 625 and reliance on external Boeing service bulletin revisions for method and approval (Requirement 2; references to Boeing SB 747-76A2083 Revision 1 and Revision 2).","Dependency on an external document and reference to foreign regulator action (FAA AD 93-17-06) increases procedural coordination.","Safety-critical consequence (loss of engine thrust control) concentrates risk and raises the importance of timely compliance (Background).","A cancellation clause where replacing with Inconel 625 removes ongoing inspection obligations, creating a compliance trade-off between recurring inspection cost and one-off replacement cost (Note)."],"plain_english_summary":"Requires operators of Boeing 747s (line numbers 202–886) with GE CF6‑45/50 engines to inspect the engine thrust‑control idler pulley support bracket for cracking, permits a temporary repair for a single crack under 2.0 inches, and mandates replacement of aluminium brackets with Inconel 625 parts per Boeing service bulletins. Inspections and replacements must meet specified flight‑hour and date deadlines; replacing with Inconel 625 removes the inspection requirement. Operators pay for inspections, repairs and parts and must follow the Boeing SB procedures."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical failure mode in a defined aircraft population. The scope remains precisely limited to the identified bracket cracking issue and the prescribed remedy."},"complexity_factors":["Single, specific mechanical component addressed (idler pulley support bracket)","Clear applicability criteria (line numbers 202-886, specific engine type)","Two-tier compliance structure (inspection + replacement) with straightforward timelines","Cross-reference to one FAA AD and two Boeing Service Bulletins (SBs)","Simple conditional logic: 'if cracked less than 2.0 inches, may remain in service with interim repair'","No nested definitions or extensive interpretation sections","Total length: approximately 250 words"],"plain_english_summary":"This CASA Airworthiness Directive orders operators of Boeing 747s (line numbers 202–886) with GE CF6‑45/50 engines to inspect and, where needed, temporarily repair or permanently replace the idler cable pulley support bracket in the engine thrust control system.  \n\nCracks have been reported and a fractured bracket could cause loss of engine thrust control; the AD mandates recurring inspections and eventual replacement with an Inconel 625 bracket to eliminate the hazard."}},"importantCases":[],"_links":{"self":"/api/acts/ad-b747-144-engine-thrust-control-idler-cable-pulley-support-bracket","history":"/api/acts/ad-b747-144-engine-thrust-control-idler-cable-pulley-support-bracket/history","analysis":"/api/acts/ad-b747-144-engine-thrust-control-idler-cable-pulley-support-bracket/analysis","conflicts":"/api/acts/ad-b747-144-engine-thrust-control-idler-cable-pulley-support-bracket/conflicts","importantCases":"/api/acts/ad-b747-144-engine-thrust-control-idler-cable-pulley-support-bracket/important-cases","documents":"/api/acts/ad-b747-144-engine-thrust-control-idler-cable-pulley-support-bracket/documents"}}