{"id":"F2006B06554","name":"AD/RB211/23 - HP Compressor Rotor Shaft to HP Turbine Rotor Disc Retaining Bolts","slug":"ad-rb211-23-hp-compressor-rotor-shaft-to-hp-turbine-rotor-disc-retaining-bolts","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48285,"registerId":"commonwealth-F2006B06554-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.002.png)\n\n![](image.002.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.","sortOrder":0},{"sectionNumber":"AD/RB211/23 HP Compressor Rotor Shaft to","sectionType":"part","heading":"AD/RB211/23 HP Compressor Rotor Shaft to HP Turbine","content":"# AD/RB211/23 HP Compressor Rotor Shaft to HP Turbine\n\nRotor Disc Retaining Bolts\n\nApplicability: RB211-524G2, \\-524G3 and 524H2 series engines.","sortOrder":1},{"sectionNumber":"8/2000","sectionType":"part","heading":"8/2000","content":"# AD/RB211/23 HP Compressor Rotor Shaft to HP Turbine\n\nRotor Disc Retaining Bolts\n\nApplicability: RB211-524G2, \\-524G3 and 524H2 series engines.\n\n#   \n8/2000","sortOrder":2}],"analysis":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The instrument, as supplied, applies to RB211-524G2, -524G3 and 524H2 series engines and mandates corrective action under subregulation 39.1(1) of CAR 1998. There is no information in the provided text indicating the AD's scope differs from its stated applicability or purpose."},"complexity_factors":["Technical engineering subject: concerns HP compressor-rotor-shaft to HP turbine rotor-disc retaining bolts (Applicability) — requires specialist maintenance and engineering competence.","Mandatory regulatory power under subregulation 39.1(1) of CAR 1998 creates binding obligations and an enforceable compliance timetable (subreg 39.1(1) cited).","Applicability is narrowly defined to specific RB211 engine series, concentrating impact on operators that use those engines (Applicability).","Key operational details (the exact corrective actions, timings and instructions) are set out in the Requirement and Compliance sections but are not included in the supplied text, increasing implementation uncertainty.","Financial and resource burden falls to operators or their maintenance organisations who must perform and fund the required work (Requirement/Compliance as described).","Decisionmaker concentration: a CASA delegate issues and prescribes the required measures, centralising procedural discretion (delegate signature and subreg 39.1(1))."],"plain_english_summary":"This Airworthiness Directive requires corrective action concerning the HP compressor-rotor-shaft to HP turbine rotor-disc retaining bolts on RB211-524G2, -524G3 and 524H2 series engines (Applicability). It addresses an identified unsafe condition by mandating the actions set out in the AD. The CASA delegate issues the AD under subregulation 39.1(1) of CAR 1998 and prescribes the work, timing and instructions; affected operators or maintenance organisations must carry out and fund the required actions within the AD's compliance schedule (Requirement, Compliance sections)."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This appears to be a standard, targeted Airworthiness Directive addressing a specific safety-critical mechanical defect in defined engine models. There is no indication of scope creep; it maintains the typical narrow focus of ADs on particular unsafe conditions."},"complexity_factors":["Short, single-issue directive focused on one specific mechanical component","Limited applicability — only three specific engine variants affected","Standard CASA AD structure with clearly separated sections (Applicability, Requirement, Compliance)","No complex cross-referencing to other legislation or regulations beyond the basic CAR 1998 citation","Technical content is straightforward mechanical engineering rather than legal conditional logic","Missing the actual Requirement and Compliance sections in this extract, which would contain the detailed instructions"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a safety order issued by the Civil Aviation Safety Authority (CASA) that legally requires aircraft owners or operators to fix a specific safety problem.\n\n**What it does:**\nThis directive targets a specific mechanical fault in certain Rolls-Royce jet engines (the RB211-524G2, -524G3, and 524H2 series). The problem involves the **retaining bolts** that hold together two critical rotating parts: the High Pressure (HP) Compressor Rotor Shaft and the HP Turbine Rotor Disc. If these bolts fail, the engine could break apart in flight.\n\n**Who it affects:**\n- Airlines or operators flying aircraft with these specific Rolls-Royce RB211 engine models\n- Maintenance organisations servicing these engines\n\n**What must be done:**\nThe directive legally mandates specific inspection or replacement actions (detailed in the \"requirement section\" referenced but not fully shown here) to prevent bolt failure. These actions must be performed:\n- When specified conditions are met (mentioned in the requirement section)\n- Following exact instructions provided\n- By the deadline set in the compliance section\n\n**Why it matters:**\nEngine rotor failures can cause catastrophic damage, potentially destroying the engine and endangering the aircraft. This AD prevents that by forcing operators to address a known design or manufacturing defect before it causes an accident."}},"importantCases":[],"_links":{"self":"/api/acts/ad-rb211-23-hp-compressor-rotor-shaft-to-hp-turbine-rotor-disc-retaining-bolts","history":"/api/acts/ad-rb211-23-hp-compressor-rotor-shaft-to-hp-turbine-rotor-disc-retaining-bolts/history","analysis":"/api/acts/ad-rb211-23-hp-compressor-rotor-shaft-to-hp-turbine-rotor-disc-retaining-bolts/analysis","conflicts":"/api/acts/ad-rb211-23-hp-compressor-rotor-shaft-to-hp-turbine-rotor-disc-retaining-bolts/conflicts","importantCases":"/api/acts/ad-rb211-23-hp-compressor-rotor-shaft-to-hp-turbine-rotor-disc-retaining-bolts/important-cases","documents":"/api/acts/ad-rb211-23-hp-compressor-rotor-shaft-to-hp-turbine-rotor-disc-retaining-bolts/documents"}}