{"id":"F2006B07312","name":"AD/TB20/1 - Engine Mount - Inspection/Replacement","slug":"ad-tb20-1-engine-mount-inspection-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49327,"registerId":"commonwealth-F2006B07312-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TB20/1 - Engine Mount - Inspection/Replacement","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 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Aerospatiale (Socata) TB20 (Trinidad) Series Aeroplanes\n\n \n\nAD/TB20/1 Engine Mount - Inspection/Replacement 9/84\n\nApplicability: To model TB20 with S/Nos. 339, 355, 358, 360, 379, 380, 384, 385 and 386. Requirement:               a. Inspect engine mount P/No. TB20.51.000.001 for the following S/Nos. 37, 38, 39,\n\n40, 47, 43, 51, 50 and 45.\n\n \n\nb. Replace any of the above and install an engine mount P/No. TB20.51.000.001 made of 15CDV6 steel not bearing one of the above numbers.\n\n \n\nNote: Aerospatiale SB No. 20 GR 71-09 refers.\n\n \n\nCompliance: Before further flight.\n\n \n\nBackground: The manufacturer reports that the subject engine mounts were manufactured from an incorrect specification steel.\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":1664},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive maintains its original narrow scope targeting the specific manufacturing defect in engine mounts for the identified aircraft batch, with no expansion into broader operational or maintenance requirements."},"complexity_factors":["Narrow applicability limited to 9 specific aircraft serial numbers","Precise identification required using both part numbers and component serial numbers","Single unconditional compliance requirement with no exceptions","Immediate effective date (before further flight) with no grace period"],"plain_english_summary":"This urgent safety order affects owners/operators of Aerospatiale TB20 Trinidad aircraft serials 339, 355, 358, 360, 379, 380, 384, 385, and 386. You must inspect engine mount part TB20.51.000.001 and, if its serial is 37, 38, 39, 40, 47, 43, 51, 50, or 45, replace it with a mount made of the correct 15CDV6 steel before the aircraft flies (aircraft grounded until done). The mounts were made from the wrong steel and could fail, risking engine separation."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tb20-1-engine-mount-inspection-replacement","history":"/api/acts/ad-tb20-1-engine-mount-inspection-replacement/history","analysis":"/api/acts/ad-tb20-1-engine-mount-inspection-replacement/analysis","conflicts":"/api/acts/ad-tb20-1-engine-mount-inspection-replacement/conflicts","importantCases":"/api/acts/ad-tb20-1-engine-mount-inspection-replacement/important-cases","documents":"/api/acts/ad-tb20-1-engine-mount-inspection-replacement/documents"}}