{"id":"F2006B08468","name":"AD/CF6/25 - Fan Disks - Removal From Service","slug":"ad-cf6-25-fan-disks-removal-from-service","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51125,"registerId":"commonwealth-F2006B08468-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CF6/25 - Fan Disks - Removal From Service","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\nAD/CF6/25 Fan Disks - Removal From Service 10/92\n\nApplicability: CF6-50 and 80A series.\n\nRequirement: Action in accordance with the technical requirements of FAA AD 91-23-13. Compliance:              As specified in the Requirement Document with an effective date of 17 September\n\n1992.\n\n \n\nBackground:  This AD requires removal of certain Stage 1 Fan Disks from service. It results from the possibility of a metallurgical defect which could adversely affect the service life of the disc.\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\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive with a single purpose. There is no indication of scope creep; it addresses one specific defect in one specific engine component with a clear removal mandate."},"complexity_factors":["Extremely short document (approximately 150 words)","No defined terms section — relies entirely on external reference to FAA AD 91-23-13","Single, unambiguous requirement: remove specified fan disks","No nested conditions, exceptions, or cross-references within the document itself","Simple applicability clause limited to two engine series","Compliance date is absolute (single fixed date) rather than conditional"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA).\n\n**What it does:**\nIt orders airlines and aircraft operators to remove specific **Stage 1 Fan Disks** from certain General Electric jet engines (the CF6-50 and CF6-80A series). These are large turbine engines commonly used on wide-body aircraft like Boeing 747s and Airbus A300s.\n\n**Why it matters:**\nThe directive was triggered by the discovery of a potential **metallurgical defect** — a flaw in the metal manufacturing process that could cause the fan disk to fail prematurely. A failed fan disk can destroy an engine and potentially endanger the aircraft and passengers.\n\n**Who must comply:**\nAny Australian operator flying aircraft with these specific engine models must follow the technical requirements set out in the corresponding US Federal Aviation Administration (FAA) directive (AD 91-23-13) and complete the removal by **17 September 1992**.\n\n**In short:** This is a safety recall for aircraft engine parts — mandatory, time-sensitive, and designed to prevent catastrophic engine failure."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument maintains a focused, model-specific requirement: remove certain Stage 1 Fan Disks on CF6-50 and CF6-80A engines and follow the technical steps in FAA AD 91-23-13 (Applicability; Requirement; Background). There is no indication in the text that the scope changed from the instrument's stated purpose of removing disks because of a possible metallurgical defect."},"complexity_factors":["Reference to an external technical document (FAA AD 91-23-13) rather than including procedures increases procedural complexity for implementers","Technical subject matter (Stage 1 Fan Disk metallurgy and service-life implications) requires specialist maintenance knowledge","Limited applicability to specific engine-series narrows scope but requires checks across operator fleets to identify affected assets","Compliance timing (effective date specified) creates operational scheduling complexity for maintenance planning","Cross-jurisdiction coordination: domestic adoption of an FAA directive means implementers must access and interpret a foreign regulator's technical requirements"],"plain_english_summary":"This instrument requires operators of aircraft with General Electric CF6‑50 and CF6‑80A engines to remove certain Stage 1 fan disks from service because of a possible metallurgical defect that could shorten disk life and threaten safety. \n\nCompliance means following the technical steps in FAA Airworthiness Directive 91‑23‑13 (effective 17 September 1992). Practically, operators face inspection, removal and replacement costs, aircraft downtime, and reliance on the FAA document for detailed procedures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf6-25-fan-disks-removal-from-service","history":"/api/acts/ad-cf6-25-fan-disks-removal-from-service/history","analysis":"/api/acts/ad-cf6-25-fan-disks-removal-from-service/analysis","conflicts":"/api/acts/ad-cf6-25-fan-disks-removal-from-service/conflicts","importantCases":"/api/acts/ad-cf6-25-fan-disks-removal-from-service/important-cases","documents":"/api/acts/ad-cf6-25-fan-disks-removal-from-service/documents"}}