{"id":"F2006B06568","name":"AD/RB211/8 - H.P. Compressor Rotor Stage 4 to 6 Shaft Assembly - Life Limitation","slug":"ad-rb211-8-h-p-compressor-rotor-stage-4-to-6-shaft-assembly-life-limitation","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48330,"registerId":"commonwealth-F2006B06568-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/RB211/8 - H.P. Compressor Rotor Stage 4 to 6 Shaft Assembly - Life Limitation","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 - RB211 Series\n\n \n\nAD/RB211/8 H.P. Compressor Rotor Stage 4 to 6\n\nShaft Assembly - Life Limitation\n\n\n5/83\n\n \n\nCANCELLED.\n\n \n\nBackground: Extensive laboratory investigation and stress analysis has now shown that the life restriction placed upon the affected assemblies by Rolls Royce RB211 SB211-72- 6420 can be removed. They can now assume the same life as their unaffected equivalent parts.\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\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This AD performs exactly its intended function — removing a previously imposed life limitation. The scope remains precisely targeted at the specific RB211 engine part mentioned in the original directive."},"complexity_factors":["Extremely short document — only 4 substantive lines of text","No defined terms section","No cross-references to other legislation (only references a Rolls-Royce service bulletin for context)","No conditional logic or exceptions","Single, straightforward operative provision: 'CANCELLED'","Essentially a notification of revocation with brief explanatory background"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety instruction issued by Australia's Civil Aviation Safety Authority (CASA) that tells aircraft operators what they must do to keep their planes airworthy.\n\n**What it does:** This particular AD **cancels a previous safety restriction** on a specific Rolls-Royce jet engine part. The part in question is the **high-pressure (H.P.) compressor rotor shaft assembly** covering stages 4 to 6 in Rolls-Royce RB211 series engines (commonly used in wide-body aircraft like the Boeing 747).\n\n**The backstory:** Previously, Rolls-Royce had issued a service bulletin (SB211-72-6420) that imposed a **life limit** on these shaft assemblies — meaning they had to be replaced after a certain number of flight hours or cycles, even if they looked fine. This AD removes that restriction.\n\n**Why it changed:** Extensive lab testing and stress analysis showed the parts were actually more durable than originally thought. The affected assemblies can now stay in service as long as their unaffected counterparts — no special early retirement required.\n\n**Who it affects:** Airlines and operators flying aircraft with RB211 engines, plus maintenance organisations that service these engines.\n\n**Why it matters:** This saves money and reduces waste. Instead of scrapping or overhauling perfectly good engine parts prematurely, operators can keep using them for their full designed lifespan."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The original scope imposed a life limitation on the H.P. compressor rotor Stage 4–6 shaft assembly (per Rolls-Royce SB211-72-6420). The AD entry now cancels that restriction and permits those assemblies to assume the same life as unaffected equivalent parts, thereby narrowing the regulatory constraint on those specific parts."},"complexity_factors":["Very short source text with limited technical detail (low information density).","Dependence on manufacturer's service bulletin (SB211-72-6420) and its unstated analytical details (technical analysis not reproduced in the AD).","Regulatory action is procedural (cancellation) rather than the imposition of a detailed new rule, reducing legal complexity.","Operational implementation requires updates to maintenance programs and records, which involves administrative coordination across operators and maintainers.","Potential for different operator responses (some may voluntarily retain conservative practices), creating operational heterogeneity despite a single regulatory change."],"plain_english_summary":"The cancelled AD removes a previously imposed life limit on Rolls‑Royce RB211 high‑pressure compressor Stage 4–6 shaft assemblies, so affected parts may now be treated the same as their unaffected equivalents. This affects operators, maintenance organisations and CASA oversight because it reduces mandated replacement frequency, lowers compliance and spare‑parts costs, and requires updates to maintenance records and programs. The change is based on Rolls‑Royce’s laboratory and stress‑analysis findings cited in the AD."}},"importantCases":[],"_links":{"self":"/api/acts/ad-rb211-8-h-p-compressor-rotor-stage-4-to-6-shaft-assembly-life-limitation","history":"/api/acts/ad-rb211-8-h-p-compressor-rotor-stage-4-to-6-shaft-assembly-life-limitation/history","analysis":"/api/acts/ad-rb211-8-h-p-compressor-rotor-stage-4-to-6-shaft-assembly-life-limitation/analysis","conflicts":"/api/acts/ad-rb211-8-h-p-compressor-rotor-stage-4-to-6-shaft-assembly-life-limitation/conflicts","importantCases":"/api/acts/ad-rb211-8-h-p-compressor-rotor-stage-4-to-6-shaft-assembly-life-limitation/important-cases","documents":"/api/acts/ad-rb211-8-h-p-compressor-rotor-stage-4-to-6-shaft-assembly-life-limitation/documents"}}