{"id":"F2006B02277","name":"AD/AL 250/66 Amdt 2 - Second Stage Turbine Wheel","slug":"ad-al-250-66-amdt-2-second-stage-turbine-wheel","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41507,"registerId":"commonwealth-F2006B02277-current","compilationNumber":null,"startDate":"2026-04-01","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AL 250/66 Amdt 2 - Second Stage Turbine Wheel","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nAllison Turbine Engines \\- 250 Series\n\nAD/AL 250/66\n\nAmdt 2\n\n  \nSecond Stage Turbine Wheel 12/89\n\nApplicability: Allison model 250-C30, C30L, C30M, C30P, C30S engines.\n\nRequirement: Install a second stage turbine wheel P/N 23032280 in accordance with the requirements of Allison Alert Service Bulletin CEB-A-72-3132, or CEB-A-72-3137 Rev.2 as applicable.\n\nNote: This Directive should be carried out in conjunction with CAO 106 AD/AL 250/64 Amdt 3. FAA AD 86-19-12 refers.\n\nCompliance: As detailed in Requirement document.\n\nBackground: This Directive has been amended to increase the engine models and helicopters affected. The requirement to install a higher burst speed second stage turbine wheel is now applicable to all C30 series engines, regardless of the type of helicopter to which the engine is fitted.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1886},"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":true,"description":"The directive has expanded significantly from its original scope. It now applies to all C30 series engines regardless of helicopter type, whereas previously it was limited to specific engine models and helicopter combinations. The background explicitly notes this amendment increases the range of affected engine models and helicopters."},"complexity_factors":["Technical aviation terminology requiring specialised knowledge (turbine wheels, part numbers)","External references to manufacturer service bulletins (CEB-A-72-3132, CEB-A-72-3137 Rev.2)","Cross-references to other airworthiness directives and foreign (FAA) regulations","Specific applicability criteria based on five engine model variants"],"plain_english_summary":"This mandatory Airworthiness Directive requires operators and maintenance organisations to replace the second-stage turbine wheel in Allison 250‑C30 series engines with part number 23032280 per manufacturer service bulletin CEB‑A‑72‑3132 or CEB‑A‑72‑3137 Rev 2. It expands the safety requirement to all C30 engines to reduce the risk of catastrophic engine failure by using a wheel with a higher burst-speed rating. Compliance timelines align with the referenced service bulletins and related directives."}},"importantCases":[],"_links":{"self":"/api/acts/ad-al-250-66-amdt-2-second-stage-turbine-wheel","history":"/api/acts/ad-al-250-66-amdt-2-second-stage-turbine-wheel/history","analysis":"/api/acts/ad-al-250-66-amdt-2-second-stage-turbine-wheel/analysis","conflicts":"/api/acts/ad-al-250-66-amdt-2-second-stage-turbine-wheel/conflicts","importantCases":"/api/acts/ad-al-250-66-amdt-2-second-stage-turbine-wheel/important-cases","documents":"/api/acts/ad-al-250-66-amdt-2-second-stage-turbine-wheel/documents"}}