{"id":"F2010L02761","name":"AD/CF6/81 - Low Pressure Turbine (LPT) Nozzle Lock Assembly Studs","slug":"ad-cf6-81-low-pressure-turbine-lpt-nozzle-lock-assembly-studs","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":84718,"registerId":"commonwealth-F2010L02761-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"General Electric Turbine Engines - CF6 S","sectionType":"division","heading":"General Electric Turbine Engines - CF6 Series","content":"### General Electric Turbine Engines \\- CF6 Series\n\n| AD/CF6/81 | Low Pressure Turbine (LPT)Nozzle Lock Assembly Studs | 21/2010 |\n| --------- | ---------------------------------------------------- | ------- |\n\n| Applicability: | General Electric Company CF6 engines as specified in FAA AD 2001-04-16.                                                                                                                                                                                                                                                                                                                                                                                                                                                      |\n| -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Unless already accomplished, perform the actions and inspections in accordance with the requirements of FAA AD 2001-04-16.Repeat the inspections in accordance with the requirements of FAA AD 2001-04-16.Later revisions to the Service Bulletins referred in the Requirement Document that are approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2001-04-16, are considered acceptable for compliance with the equivalent Requirements of this AD. |\n| Compliance:    | As specified in the Requirement Document with a revised effective date of11 November 2010.                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n|                | This Airworthiness Directive becomes effective on 11 November 2010.                                                                                                                                                                                                                                                                                                                                                                                                                                                          |\n| Background:    | This AD is prompted by a report of an uncontained engine failure. The actions specified in this AD are intended to detect cracked, loose or missing stage 2 LPT nozzle lock assembly studs that could lead to failure of the locks, nozzle segment rotation, LPT case machining, and subsequent uncontained failure of the engine. The actions also provide for modifications of nozzle lock assemblies if the nozzle lock studs are found cracked, loose, or missing.                                                       |\n\n![](image.001.png)\n\nMike Higgins  \nDelegate of the Civil Aviation Safety Authority\n\n18 October 2010","sortOrder":0},{"sectionNumber":"AD/CF6/81","sectionType":"part","heading":"AD/CF6/81","content":"## AD/CF6/81","sortOrder":1},{"sectionNumber":"Low Pressure Turbine (LPT)Nozzle Lock As","sectionType":"part","heading":"Low Pressure Turbine (LPT)Nozzle Lock Assembly Studs","content":"## Low Pressure Turbine (LPT)  \nNozzle Lock Assembly Studs","sortOrder":2},{"sectionNumber":"21/2010","sectionType":"part","heading":"21/2010","content":"## 21/2010","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":false,"description":"This AD adopts and enforces the requirements of FAA AD 2001-04-16 for the specified CF6 engines and accepts FAA‑approved alternate methods of compliance. The instrument does not indicate an expansion beyond the FAA AD’s technical scope; it transposes those requirements into the national regulatory framework with an effective date of 11 November 2010 (Applicability; Requirement; Compliance)."},"complexity_factors":["Cross-reference to FAA AD 2001-04-16 for mandatory actions and inspection intervals (Requirement) — compliance depends on an external, technical document.","Technical nature of inspections and potential modifications of LPT nozzle lock assemblies requires specialised maintenance skills, tooling and engine access (Background; Requirement).","Repeating inspections over time increases ongoing operational and maintenance scheduling burden for operators (Requirement).","Acceptance of FAA‑approved AMOCs introduces regulatory discretion and potential variation in compliance methods (Requirement).","Applicability limited to specified CF6 engines requires fleet-level identification and record checks to determine which aircraft are in scope (Applicability).","Safety‑critical consequences (uncontained engine failure) raise enforcement and documentation requirements for regulators and operators (Background).","Compliance effective date and administrative adoption by the national authority require coordination between CASA enforcement and operator implementation (Compliance; Effective date)."],"plain_english_summary":"This Airworthiness Directive requires operators of specified General Electric CF6 turbine engines to carry out the inspections and corrective actions in FAA AD 2001-04-16 to detect and fix cracked, loose or missing low‑pressure turbine (LPT) nozzle lock assembly studs. Engine owners/operators must perform repeated inspections and make any required modifications; compliance follows the FAA AD timetable and FAA‑approved alternate methods of compliance are accepted. The directive matters because studs failure can lead to nozzle rotation and uncontained engine failure, so it imposes inspection, repair and compliance costs on operators."},"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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a standard airworthiness directive with a narrow, specific safety purpose. It has not expanded beyond its original intent of addressing the LPT nozzle lock assembly stud failure risk."},"complexity_factors":["Short, single-purpose directive with one primary requirement","No defined terms section — relies entirely on external FAA document (AD 2001-04-16) for technical specifications","Single cross-reference to external US regulation rather than detailed domestic provisions","Minimal conditional logic — essentially 'inspect and repair if needed' with repeat intervals","No nested exceptions or complex compliance pathways"],"plain_english_summary":"This CASA Airworthiness Directive mandates repetitive inspections of low‑pressure turbine nozzle lock assembly studs on specified GE CF6 engines and requires repair or modification if studs are cracked, loose, or missing. It applies to Australian operators of affected CF6‑powered wide‑body aircraft.\n\nThe action prevents turbine nozzle rotation and engine‑case damage that can cause uncontained engine failure — prompted by a real incident — and was made mandatory from 11 November 2010."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf6-81-low-pressure-turbine-lpt-nozzle-lock-assembly-studs","history":"/api/acts/ad-cf6-81-low-pressure-turbine-lpt-nozzle-lock-assembly-studs/history","analysis":"/api/acts/ad-cf6-81-low-pressure-turbine-lpt-nozzle-lock-assembly-studs/analysis","conflicts":"/api/acts/ad-cf6-81-low-pressure-turbine-lpt-nozzle-lock-assembly-studs/conflicts","importantCases":"/api/acts/ad-cf6-81-low-pressure-turbine-lpt-nozzle-lock-assembly-studs/important-cases","documents":"/api/acts/ad-cf6-81-low-pressure-turbine-lpt-nozzle-lock-assembly-studs/documents"}}