{"id":"F2006B06680","name":"AD/RRT-S/11 - Steel Turbine Discs","slug":"ad-rrt-s-11-steel-turbine-discs","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48685,"registerId":"commonwealth-F2006B06680-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/RRT-S/11 - Steel Turbine Discs","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)  Rolls Royce Turbine Engines - Spey Series\n\n \n\nAD/RRT-S/11 Steel Turbine Discs 13/92\n\nApplicability: Spey series engines as detailed in Rolls Royce Service Bulletin Sp72-1044. Requirement:               Action in accordance with the requirements of Rolls Royce Service Bulletin Sp\n\n72-1044.\n\n \n\nCompliance: Effective 10 December 1992: At next engine shop visit during which, either a low pressure turbine or a high pressure turbine overhaul is scheduled.\n\n \n\nBackground:  This Directive requires steel turbine discs which have completed at least 40% of their published service life, to be inspected in accordance with the overhaul manual. The requirement addresses concern with evidence of low cycle fatigue cracks originating from corrosion pits in a number of Spey steel turbine discs.\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":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical failure mode in a specific engine type. It has not expanded beyond its original purpose of mandating inspections for corrosion-induced fatigue cracking in Spey steel turbine discs."},"complexity_factors":["Single, clearly defined applicability (Spey series engines per specific Service Bulletin)","Only one substantive requirement (follow Rolls-Royce Service Bulletin Sp 72-1044)","Simple compliance trigger (next scheduled overhaul of specified turbine components)","No defined terms section, no cross-references to other legislation, no nested conditions","Background explanation provided in plain language","Extremely short document (approximately 150 words of substantive content)"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspection of steel turbine discs in Rolls‑Royce Spey engines once they have reached at least 40% of their design life, to be performed at the next major engine shop visit. \n\nIt affects airlines, military and civilian operators, and maintenance organisations using Spey engines, aiming to detect low‑cycle fatigue cracks that originate from corrosion pits and could cause catastrophic engine failure."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument, as written, implements a targeted inspection requirement for Spey-series steel turbine discs that have completed at least 40% of published life and fixes compliance timing to the next relevant overhaul. The text does not indicate an expansion or narrowing of scope beyond that targeted requirement."},"complexity_factors":["Targeted scope limited to Rolls‑Royce Spey-series steel turbine discs (explicit applicability).","A clear service‑life threshold (>= 40% of published life) that triggers inspection.","Reliance on external technical documents for procedure: Rolls‑Royce Service Bulletin Sp72‑1044 and the overhaul manual (procedural complexity outsourced).","Compliance timing tied to next scheduled low‑ or high‑pressure turbine overhaul (operational scheduling dependency).","Technical inspection and any repair outcomes require specialised maintenance facilities and certification (practical compliance cost).","Short, prescriptive directive with no broad administrative discretion or complex enforcement regime."],"plain_english_summary":"This airworthiness directive requires operators of Rolls‑Royce Spey-series engines to inspect steel turbine discs that have reached at least 40% of their published service life, following Rolls‑Royce Service Bulletin Sp72‑1044 and the engine overhaul manual. Inspections must be done at the next scheduled low- or high-pressure turbine overhaul (Compliance: effective 10 December 1992). The rule responds to evidence of low‑cycle fatigue cracks from corrosion pits. Operators and maintenance organisations must arrange and pay for inspection and any remedial work."}},"importantCases":[],"_links":{"self":"/api/acts/ad-rrt-s-11-steel-turbine-discs","history":"/api/acts/ad-rrt-s-11-steel-turbine-discs/history","analysis":"/api/acts/ad-rrt-s-11-steel-turbine-discs/analysis","conflicts":"/api/acts/ad-rrt-s-11-steel-turbine-discs/conflicts","importantCases":"/api/acts/ad-rrt-s-11-steel-turbine-discs/important-cases","documents":"/api/acts/ad-rrt-s-11-steel-turbine-discs/documents"}}