{"id":"F2006B07252","name":"AD/T53/4 - Engine Oil Pump Drive Gear Spline - Inspection","slug":"ad-t53-4-engine-oil-pump-drive-gear-spline-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49145,"registerId":"commonwealth-F2006B07252-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/T53/4 - Engine Oil Pump Drive Gear Spline - Inspection","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)  AlliedSignal (Lycoming) Turbine Engines - T53 Series\n\n \n\nAD/T53/4 Engine Oil Pump Drive Gear Spline - Inspection 1/86\n\nApplicability: All model T5311A engines S/N LE08149 to LE08293 not incorporating Overhaul Modification Bulletin No. 0028: Field Service Bulletin No. 0010, or Lycoming SB No. 41.\n\n \n\nDocument: 1. Lycoming SB No. 40; or\n\n \n\n2.        Lycoming Field Service Bulletin No. 0013; or\n\n \n\n3.        Lycoming Overhaul Modification bulletin No. 0027; or\n\n \n\n4.        AD/LYC-T/2.\n\n \n\nCompliance: In accordance with the requirement documents.\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":1359},"content_quality":"ok","complexity_score":2,"rejection_reason":"","scope_assessment":{"changed":false,"description":"This directive remains tightly focused on its original 1986 safety purpose: inspecting specific T53 engine oil pump splines. There is no evidence of scope expansion beyond this specific mechanical defect in the identified engine series."},"complexity_factors":["Extremely narrow applicability limited to specific engine model and serial number range","Only 4 external document references with no internal procedural detail","Single compliance requirement ('In accordance with the requirement documents')","No defined terms section, no conditional logic, no penalty provisions"],"plain_english_summary":"This mandatory Airworthiness Directive requires operators to inspect the oil pump drive gear spline on Lycoming T53 T5311A engines (S/N LE08149–LE08293) unless the engine has already been modified per specified Lycoming bulletins.  \n\nInspections must follow one of the referenced Lycoming service/overhaul documents; the goal is to detect spline wear that could stop oil pumping and cause catastrophic engine seizure. Compliance is legally required."}},"importantCases":[],"_links":{"self":"/api/acts/ad-t53-4-engine-oil-pump-drive-gear-spline-inspection","history":"/api/acts/ad-t53-4-engine-oil-pump-drive-gear-spline-inspection/history","analysis":"/api/acts/ad-t53-4-engine-oil-pump-drive-gear-spline-inspection/analysis","conflicts":"/api/acts/ad-t53-4-engine-oil-pump-drive-gear-spline-inspection/conflicts","importantCases":"/api/acts/ad-t53-4-engine-oil-pump-drive-gear-spline-inspection/important-cases","documents":"/api/acts/ad-t53-4-engine-oil-pump-drive-gear-spline-inspection/documents"}}