{"id":"F2006B08495","name":"AD/CF6/6 - First Stage High Pressure Turbine Disc Embossment Radii","slug":"ad-cf6-6-first-stage-high-pressure-turbine-disc-embossment-radii","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51195,"registerId":"commonwealth-F2006B08495-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CF6/6 - First Stage High Pressure Turbine Disc Embossment Radii","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/CF6/6 First Stage High Pressure Turbine Disc Embossment Radii\n\nApplicability: CF6-45, -50 Series engines.\n\n# 8/86\n\n \n\nRequirement: Remove from service, first stage high pressure turbine discs identified by serial number in General Electric S.B. A72-859, Rev 1, and return to manufacturer for inspection of both the forward and aft embossment radii.\n\n \n\nReference Document - FAA AD 86-12-03, Amdt 39-5311.\n\n \n\nCompliance: Prior to 5,500 cycles disc life since new.\n\n \n\nBackground:  This Directive has been issued to require removal from service, certain first stage high pressure turbine discs. The manufacturer advises, the discs may contain stress risers 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","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue safety directive addressing a specific manufacturing defect in specific engine components. It has not expanded beyond its original purpose of mandating inspection/removal of suspect turbine discs."},"complexity_factors":["Single, unambiguous requirement with no exceptions or conditional logic","Only 2 defined applicability criteria (engine models CF6-45 and CF6-50)","No cross-references to other legislation or regulations beyond a single FAA reference document","Clear, absolute compliance deadline (prior to 5,500 cycles)","No interpretation section or defined terms","Total length: approximately 150 words of substantive content"],"plain_english_summary":"This CASA Airworthiness Directive requires operators of aircraft with General Electric CF6-45 and CF6-50 engines to remove certain first-stage high-pressure turbine discs from service before 5,500 flight cycles due to possible manufacturing “stress risers” that can initiate cracks.  \n\nAffected discs must be identified by serial number (per GE Service Bulletin A72-859) and returned to the manufacturer for inspection to prevent in‑flight engine failure."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive applies only to CF6-45 and CF6-50 engines and to discs listed by serial number in the referenced GE service bulletin, requiring inspection before 5,500 cycles. It does not expand or narrow that stated applicability or compliance time beyond the document’s original terms."},"complexity_factors":["Direct, single-action requirement: remove listed discs and return for inspection (Requirement clause).","Cross-reference dependency: identification depends on GE Service Bulletin A72-859 Rev 1 (Requirement), requiring operators to match serial numbers.","Fixed compliance window: inspection must occur prior to 5,500 cycles since new (Compliance), creating scheduling pressure.","Third-party inspection: disc inspection performed by manufacturer imposes logistics and cost on operators (Requirement).","Regulatory enforcement: issued as an AD under Civil Aviation Regulations, so non-compliance carries operational/legal consequences (header/Authority).","Safety rationale limited to manufacturer’s advice that embossment radii may contain stress risers (Background), leaving technical judgement to manufacturer/regulator rather than the directive text."],"plain_english_summary":"This airworthiness directive requires removal from service of specified first-stage high-pressure turbine discs on General Electric CF6‑45 and CF6‑50 engines and their return to the manufacturer for inspection of the forward and aft embossment radii. The discs are identified by serial number in GE Service Bulletin A72‑859 Rev 1 and must be inspected before reaching 5,500 cycles since new. The manufacturer says embossment radii may contain stress risers that could shorten disc life. Operators bear removal, return and downtime costs; the regulator enforces compliance."}},"importantCases":[],"_links":{"self":"/api/acts/ad-cf6-6-first-stage-high-pressure-turbine-disc-embossment-radii","history":"/api/acts/ad-cf6-6-first-stage-high-pressure-turbine-disc-embossment-radii/history","analysis":"/api/acts/ad-cf6-6-first-stage-high-pressure-turbine-disc-embossment-radii/analysis","conflicts":"/api/acts/ad-cf6-6-first-stage-high-pressure-turbine-disc-embossment-radii/conflicts","importantCases":"/api/acts/ad-cf6-6-first-stage-high-pressure-turbine-disc-embossment-radii/important-cases","documents":"/api/acts/ad-cf6-6-first-stage-high-pressure-turbine-disc-embossment-radii/documents"}}