{"id":"F2006B08684","name":"AD/CT58/9 - Anti-Icing Valve","slug":"ad-ct58-9-anti-icing-valve","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51828,"registerId":"commonwealth-F2006B08684-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/CT58/9 - Anti-Icing Valve","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 - CT58 Series\n\n \n\nAD/CT58/9 Anti-Icing Valve 9/85\n\nApplicability: All CT58-100-1, 100-2, 110-1, 110-2, 140-1 and 140-2 Series fitted with anti-icing valves as detailed in the requirement document with the exception of those valves that have been modified to GE SB (CT58) 75-23.\n\n \n\nDocument: General Electric SB (CT58) A75-22; or\n\n \n\nAD/GE-T/22.\n\n \n\nCompliance: Within 100 hours time in service after 31 August 1972 and thereafter at intervals not exceeding 200 hours time in service unless modified to GE SB (CT58) 75-23.\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":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1926},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This airworthiness directive maintains a narrow, technical scope focused solely on anti-icing valve maintenance for specific CT58 engine models. It has not expanded beyond its original safety purpose of preventing ice-related engine failures through mandated inspection intervals."},"complexity_factors":["Single, clearly defined applicability clause covering specific engine model variants","Straightforward compliance timeline with fixed intervals (100 hours initial, 200 hours recurring)","Single exemption condition based on specific modification status","Minimal cross-referencing to only two technical documents","No interpretation section, definitions, or nested conditional logic"],"plain_english_summary":"Mandatory safety directive requiring regular inspections of original-design anti-icing valves on GE CT58-100/110/140 helicopter engines (e.g., Bell 212/412). Inspect within 100 flight hours after 31 Aug 1972 and every 200 hours thereafter; engines modified per GE Service Bulletin CT58 75-23 are exempt.\n\nChecks follow GE Service Bulletin A75-22 or AD/GE-T/22. The rule catches faulty valves that can allow ice buildup and risk engine power loss, preventing in-flight failures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ct58-9-anti-icing-valve","history":"/api/acts/ad-ct58-9-anti-icing-valve/history","analysis":"/api/acts/ad-ct58-9-anti-icing-valve/analysis","conflicts":"/api/acts/ad-ct58-9-anti-icing-valve/conflicts","importantCases":"/api/acts/ad-ct58-9-anti-icing-valve/important-cases","documents":"/api/acts/ad-ct58-9-anti-icing-valve/documents"}}