{"id":"F2006B08455","name":"AD/CF6/11 - High Pressure Turbine Rotor - Stage 2 Disc Forward Embossment Inner Diameter Fillet Radius","slug":"ad-cf6-11-high-pressure-turbine-rotor-stage-2-disc-forward-embossment-inner-diameter-fillet-radius","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51090,"registerId":"commonwealth-F2006B08455-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CF6/11 - High Pressure Turbine Rotor - Stage 2 Disc Forward Embossment Inner Diameter Fillet Radius","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  General Electric Turbine Engines - CF6 Series\n\n \n\n# AD/CF6/11  High Pressure Turbine Rotor - Stage 2 Disc Forward Embossment Inner Diameter Fillet Radius\n\nApplicability: CF6-50/-45 series engines.\n\n# 3/89\n\nTX\n\n \n\nRequirement: Rework or inspect and rework stage 2 high pressure turbine rotor discs specified by FAA AD 89-01-02 Amendment 39-6082 in accordance with the requirements of paras (a) or (b), (c) and (d) of the AD.\n\n \n\nCompliance: Forthwith. The cycle count is to commence on the effective date specified in the AD.\n\n \n\nBackground: The FAA AD incorporates a manufacturer’s Service Bulletin which states that cracks have been found in a forward embossment inner diameter fillet and these could adversely affect engine durability. The probable cause is an undersized fillet radius which is increased by the rework specified in the AD.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The AD mirrors and implements the FAA AD and the manufacturer's Service Bulletin for CF6‑50/‑45 engines; the text does not indicate any expansion or narrowing of applicability beyond those sources and therefore does not show a change in scope from the original FAA/maker measure."},"complexity_factors":["Narrow technical scope: applies only to CF6‑50 and CF6‑45 engine series (straightforward applicability).","Cross‑reference to FAA AD 89‑01‑02 Amendment 39‑6082 and a manufacturer Service Bulletin requires readers to consult external documents for full procedures.","Requirement language references paras (a) or (b), (c) and (d) of the FAA AD, creating dependence on those subparagraphs for operative detail.","Immediate compliance (‘forthwith’) and commencement of cycle counting on the AD effective date create operational urgency and scheduling impact.","Work involves safety‑critical turbine rotor fillet machining/inspection, requiring specialised maintenance capability and potential parts/overhaul downtime."],"plain_english_summary":"Requires immediate rework or inspection-and-rework of the stage‑2 high‑pressure turbine rotor discs on General Electric CF6‑50/‑45 engines to address an undersized forward embossment inner‑diameter fillet radius. The FAA and manufacturer report cracks in that fillet which could reduce engine durability. Operators must follow the FAA AD’s specified procedures; compliance begins on the AD’s effective date and will impose inspection/repair costs and maintenance downtime for affected engines."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in specific engine models. It has not expanded beyond its original purpose of mandating repair of the Stage 2 disc fillet radius issue."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 2 defined applicability criteria (engine series)","Single requirement referencing external FAA directive rather than reproducing technical specifications","No nested exceptions or conditional logic — straightforward 'comply with external document' structure","No interpretation section or defined terms","Simple compliance timing ('forthwith') with single commencement rule"],"plain_english_summary":"This CASA Airworthiness Directive mandates immediate inspection and rework of the Stage 2 high‑pressure turbine disc fillet radius on GE CF6‑50 and CF6‑45 engines. Cracks from an undersized fillet can lead to serious engine damage or failure, so operators of affected aircraft (e.g., older 747, DC‑10, A300) must comply with the referenced FAA AD and manufacturer service bulletin."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf6-11-high-pressure-turbine-rotor-stage-2-disc-forward-embossment-inner-diameter-fillet-radius","history":"/api/acts/ad-cf6-11-high-pressure-turbine-rotor-stage-2-disc-forward-embossment-inner-diameter-fillet-radius/history","analysis":"/api/acts/ad-cf6-11-high-pressure-turbine-rotor-stage-2-disc-forward-embossment-inner-diameter-fillet-radius/analysis","conflicts":"/api/acts/ad-cf6-11-high-pressure-turbine-rotor-stage-2-disc-forward-embossment-inner-diameter-fillet-radius/conflicts","importantCases":"/api/acts/ad-cf6-11-high-pressure-turbine-rotor-stage-2-disc-forward-embossment-inner-diameter-fillet-radius/important-cases","documents":"/api/acts/ad-cf6-11-high-pressure-turbine-rotor-stage-2-disc-forward-embossment-inner-diameter-fillet-radius/documents"}}