{"id":"F2006B08479","name":"AD/CF6/37 - High Pressure Compressor Rotor (HPCR) Stages 3-9 - Replacement","slug":"ad-cf6-37-high-pressure-compressor-rotor-hpcr-stages-3-9-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51154,"registerId":"commonwealth-F2006B08479-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CF6/37 - High Pressure Compressor Rotor (HPCR) Stages 3-9 - Replacement","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nGeneral Electric Turbine Engines \\- CF6 Series\n\nAD/CF6/37 High Pressure Compressor Rotor (HPCR) Stages 3-9 \\- Replacement\n\n  \n2/98 TX\n\nApplicability: CF6-50 and \\-80C2 Series turbofan engines identified by serial number in GE Alert Service Bulletins, GE CF6-50 SB 72-A1139 and CF6-80C2 SB 72-A906, dated 17 October 1997.\n\nRequirement: Remove from service HPCR 3-9 spools identified by serial number in the appropriate service bulletin and replace with serviceable parts as follows:\n\n    (1) For GE CF6-50 series turbofan engines, remove and replace in accordance with GE CF6-50 SB 72-A1139, dated 17 October 1997.\n\n    (2) For GE CF6-80C2 series turbofan engines, remove and replace in accordance with GE CF6-80C2 SB A906, dated 17 October 1997.\n\nNote: US FAA AD 97-22-14, amendment 39-10186, dated 17 November 1997 applies.\n\nCompliance: Within 30 days of the effective date of this directive.\n\nThis airworthiness directive becomes effective on 20 November 1997.\n\nBackground: Separation of the high pressure compressor rotor (HPCR), stages 3-9 spool has been experienced recently and traced to a manufacturing fault. The spools affected have been identified by serial number and are now being withdrawn from service and replaced at the manufacturer’s expense (including manpower costs).","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific manufacturing defect in specific engine serial numbers. There is no evidence of scope creep; it remains tightly focused on the safety-critical replacement of faulty HPCR spools."},"complexity_factors":["Single, specific mechanical component targeted (HPCR stages 3-9 spool)","Only two engine series affected, identified by explicit serial numbers in referenced service bulletins","Straightforward compliance requirement: remove and replace per manufacturer's instructions","Simple deadline: 30 days from effective date","No nested exceptions, conditional logic, or alternative compliance methods","Minimal defined terms (only standard aviation terminology like 'serviceable parts')","Short document length (approximately 200 words of substantive text)"],"plain_english_summary":"This mandatory CASA Airworthiness Directive requires operators of certain General Electric CF6-50 and CF6-80C2 engines to remove and replace defective High Pressure Compressor Rotor (HPCR) stages 3–9 spools because a manufacturing defect has caused spool separations in service. It affects airlines using these engines on wide‑body aircraft and must be completed within 30 days of 20 Nov 1997.\n\nGE will cover parts and labor. The action prevents catastrophic engine failure and aligns with the FAA AD."},"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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Scope has not changed from the instrument's stated purpose: it directs removal and replacement of the identified HPCR 3–9 spools on CF6-50 and CF6-80C2 engines as listed in the GE service bulletins, with replacement costs covered by the manufacturer and a 30‑day compliance window."},"complexity_factors":["Technical specificity: applies only to CF6-50 and CF6-80C2 engines and to HPCR stages 3–9 spools identified by serial number (Applicability / Requirement).","Prescriptive action: mandatory removal and replacement must follow GE service bulletins (Requirement).","Short compliance timeframe: 30 days from the effective date creates operational scheduling pressure (Compliance).","Cost allocation: manufacturer is stated to cover parts and manpower for replacements, reducing direct operator expense but creating dependency on manufacturer performance (Background).","External cross-reference: notes applicability of US FAA AD 97-22-14, creating regulatory alignment considerations (Note).","Enforcement mechanism: issued as an airworthiness directive by the Civil Aviation Safety Authority, making compliance legally required (Header / Compliance)."],"plain_english_summary":"This directive requires operators of GE CF6-50 and CF6-80C2 engines with specific serial-numbered high‑pressure compressor (HPCR) stages 3–9 spools to remove and replace those spools within 30 days, following the GE service bulletins. The Civil Aviation Safety Authority mandates compliance; GE will provide the replacement spools and cover replacement costs, including manpower, for the affected serial numbers."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf6-37-high-pressure-compressor-rotor-hpcr-stages-3-9-replacement","history":"/api/acts/ad-cf6-37-high-pressure-compressor-rotor-hpcr-stages-3-9-replacement/history","analysis":"/api/acts/ad-cf6-37-high-pressure-compressor-rotor-hpcr-stages-3-9-replacement/analysis","conflicts":"/api/acts/ad-cf6-37-high-pressure-compressor-rotor-hpcr-stages-3-9-replacement/conflicts","importantCases":"/api/acts/ad-cf6-37-high-pressure-compressor-rotor-hpcr-stages-3-9-replacement/important-cases","documents":"/api/acts/ad-cf6-37-high-pressure-compressor-rotor-hpcr-stages-3-9-replacement/documents"}}