{"id":"F2006B07254","name":"AD/T53/6 - Overspeed Pickup Gear and Shaft - Inspection and Modification","slug":"ad-t53-6-overspeed-pickup-gear-and-shaft-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49152,"registerId":"commonwealth-F2006B07254-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/T53/6 - Overspeed Pickup Gear and Shaft - Inspection and Modification","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\n# AD/T53/6 Overspeed Pickup Gear and Shaft - Inspection\n\nand Modification Applicability: All model T5313A, T5313A S/No. Suffix \"A\", and T5313B. Document:               1.              Lycoming Field service Bulletin No. 0022, Rev. 1; and\n\n2.        Lycoming Overhaul Mod. Bulletin No. 0036, Rev. 1; or\n\n \n\n3.        AD/LYC-T/6A.\n\n# 1/86\n\n \n\nCompliance: 1. Inspect in accordance with Lycoming FSB No. 0022, Rev. 1 Part 1 within 25 hours time in service after 25 February 1971 and thereafter at intervals not exceeding 25 hours time in service until modified.\n\n \n\n2. Modify within 200 hours time in service after 30 June 1971 in accordance with Part 11 of FSB No. 0022 Rev. 1, or OMB No. 0036, Rev. 1.\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":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive remains tightly focused on its original purpose: addressing a specific mechanical defect in the overspeed pickup gear and shaft of three T53 engine variants. The scope has not expanded beyond this single component and these specific models."},"complexity_factors":["Very short document (approximately 200 words)","Only 3 defined engine models in applicability section","Simple two-step compliance structure (inspect, then modify)","Heavy reliance on external technical documents (Lycoming service bulletins) for actual implementation details — the directive itself contains no technical specifications","No nested exceptions or conditional logic","Clear, absolute deadlines (25 hours, 200 hours)","Single purpose: one component, one problem, one solution"],"plain_english_summary":"This CASA Airworthiness Directive mandates owners/operators of specified AlliedSignal (Lycoming) T53 turbine engines (T5313A, T5313A with \"A\" suffix, T5313B) to inspect the overspeed pickup gear and shaft every 25 flight hours and complete a permanent modification within 200 flight hours. It targets a component that prevents engine over‑speeding; the measures address a serious risk of uncontrolled overspeed and potential catastrophic engine failure until the defect is corrected."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The text sets applicability, inspection intervals and a modification deadline without stating any amendment to or departure from an earlier scope. There is no indication in this instrument that the covered population or required actions differ from an original intent within the provided text."},"complexity_factors":["Cross-references to external manufacturer documents (Lycoming FSB No. 0022 Rev.1; OMB No. 0036 Rev.1; AD/LYC-T/6A) — implementers must obtain and follow those documents (Applicability; Document).","Short, recurring inspection interval (every 25 hours TIS) until modification and a finite modification deadline (200 hours) — creates scheduling and operational burden (Compliance paras 1–2).","Narrow applicability by model and serial-number suffix requires accurate fleet identification to determine who is covered (Applicability).","The directive states required actions but delegates technical procedure details to the referenced Lycoming bulletins, producing dependence on external technical material (Document; Compliance).","Administrative enforcement within the airworthiness directive framework implies record-keeping and compliance verification obligations for operators (header; Compliance)."],"plain_english_summary":"This airworthiness directive requires owners/operators of AlliedSignal (Lycoming) T5313A, T5313A with serial‑number suffix “A”, and T5313B turbine engines to inspect the overspeed pickup gear and shaft and then carry out a prescribed modification. Inspections must begin within 25 hours time‑in‑service after 25 February 1971 and repeat every 25 hours until the modification is done; the modification must be completed within 200 hours after 30 June 1971 (Compliance paras 1–2). Owners/operators pay costs and manage downtime; CASA enforces the directive."}},"importantCases":[],"_links":{"self":"/api/acts/ad-t53-6-overspeed-pickup-gear-and-shaft-inspection-and-modification","history":"/api/acts/ad-t53-6-overspeed-pickup-gear-and-shaft-inspection-and-modification/history","analysis":"/api/acts/ad-t53-6-overspeed-pickup-gear-and-shaft-inspection-and-modification/analysis","conflicts":"/api/acts/ad-t53-6-overspeed-pickup-gear-and-shaft-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-t53-6-overspeed-pickup-gear-and-shaft-inspection-and-modification/important-cases","documents":"/api/acts/ad-t53-6-overspeed-pickup-gear-and-shaft-inspection-and-modification/documents"}}