{"id":"F2006B02278","name":"AD/AL 250/67 Amdt 1 - Increased Labyrinth Seal Clearance Second Stage Turbine Nozzle","slug":"ad-al-250-67-amdt-1-increased-labyrinth-seal-clearance-second-stage-turbine-nozzle","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41508,"registerId":"commonwealth-F2006B02278-current","compilationNumber":null,"startDate":"2026-04-01","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AL 250/67 Amdt 1 - Increased Labyrinth Seal Clearance Second Stage Turbine Nozzle","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)  Allison Turbine Engines - 250 Series\n\n \n\nAD/AL 250/67\n\nAmdt 1\n\n\nIncreased Labyrinth Seal Clearance Second Stage Turbine Nozzle\n\n\n12/85\n\n \n\nApplicability: All Model 250-C28B and C28C engines and turbine assemblies listed in the Requirement Document.\n\n \n\nRequirement: Allison 250-C28B, C28C CEB-72-2123 Rev 1.\n\n \n\nNote: Compliance with the previous issue of this Directive constitutes compliance with this issue.\n\n \n\nCompliance: In accordance with the Requirement Document.\n\n \n\nBackground: This Directive is amended to reference Rev 1 of CEB-72-2123 which amplifies model and turbine effectivity by serial number and clarifies para (c) of accomplishment instructions.\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":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1905},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The amendment refines and narrows the original scope by specifying affected engine serial numbers and clarifying accomplishment instructions, but does not expand beyond the original safety purpose of addressing second stage turbine nozzle seal clearance."},"complexity_factors":["Extremely brief legislative text (under 200 words)","Single requirement delegating all technical detail to external service bulletin (CEB-72-2123)","Limited applicability (only two specific engine models)","No conditional logic, exceptions, or defined terms within the text","Simple backwards compliance note (previous issue satisfies current issue)"],"plain_english_summary":"This AD requires owners/operators of Allison 250‑C28B and C28C turbine engines to follow Service Bulletin CEB‑72‑2123 Rev 1 to increase clearance of the second‑stage turbine nozzle labyrinth seal. It addresses a tight seal condition that can lead to engine damage or failure. The amendment updates the referenced service document and clarifies affected serial numbers and repair steps; prior compliance with the original 1985 directive satisfies this amendment."}},"importantCases":[],"_links":{"self":"/api/acts/ad-al-250-67-amdt-1-increased-labyrinth-seal-clearance-second-stage-turbine-nozzle","history":"/api/acts/ad-al-250-67-amdt-1-increased-labyrinth-seal-clearance-second-stage-turbine-nozzle/history","analysis":"/api/acts/ad-al-250-67-amdt-1-increased-labyrinth-seal-clearance-second-stage-turbine-nozzle/analysis","conflicts":"/api/acts/ad-al-250-67-amdt-1-increased-labyrinth-seal-clearance-second-stage-turbine-nozzle/conflicts","importantCases":"/api/acts/ad-al-250-67-amdt-1-increased-labyrinth-seal-clearance-second-stage-turbine-nozzle/important-cases","documents":"/api/acts/ad-al-250-67-amdt-1-increased-labyrinth-seal-clearance-second-stage-turbine-nozzle/documents"}}