{"id":"F2006B06560","name":"AD/RB211/3 Amdt 2 - Speed and Temperature Governing System","slug":"ad-rb211-3-amdt-2-speed-and-temperature-governing-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48304,"registerId":"commonwealth-F2006B06560-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/RB211/3 Amdt 2 - Speed and Temperature Governing System","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nRolls Royce Turbine Engines \\- RB211 Series\n\nAD/RB211/3\n\nAmdt 2\n\n  \nSpeed and Temperature Governing System 10/99\n\nApplicability: RB211 engines as detailed in Rolls Royce Service Bulletin Number RB.211-73-4305 Revision 6.\n\nRequirement: To identify possible dormant failures within the speed and temperature governing system which may prevent response of the governing system to an overspeed; carry out a maintenance test of the speed governing system as described in the Aircraft Maintenance Manual, Chapter 73-21-00, Adjustment/Test. Rolls Royce Service Bulletin Number RB.211-73-4305 Revision 6 refers.\n\nNote: The requirements of Rolls Royce Service Bulletin Number RB.211-73-4305 Revision 6 have been declared mandatory by the CAA (UK).\n\nCompliance: Unless previously accomplished; within 750 hours time in service from the effective date of this directive and thereafter at intervals not to exceed 750 hours time in service.\n\nThis Amendment becomes effective on 7 October 1999.\n\nBackground: This directive was originally issued to require a periodic test of the speed and temperature governing system. The requirement reflected advice of a dormant failure could result in the governing system not responding to an overspeed or over temperature condition.\n\nAmendment 1 was issued in June 1982 to include the RB211-524D4-19 model.\n\nThis amendment reflects the manufacturer’s latest revision to the requirement document. The revision, in part, deletes the requirement to carry out a periodic test of the temperature governing function. Automatic control of the temperature channel is no longer considered essential for the safe operation of the engine.\n\nAmendment 1 of this Airworthiness Directive became effective 30 June 1982.\n\nThe original issue of this Airworthiness Directive became effective on 31 January 1982.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":true,"description":"The scope has narrowed from the original directive. The original required testing of both speed AND temperature governing systems. This amendment removes the temperature test requirement, reducing the regulatory burden based on updated safety analysis from the manufacturer. The scope is now limited to speed governing only."},"complexity_factors":["Single, specific technical requirement (one maintenance test)","Clear applicability statement referencing a single engine series and specific service bulletin","Simple compliance timeline (750 hours recurring)","Minimal cross-referencing (only to Aircraft Maintenance Manual chapter and one Service Bulletin)","No nested exceptions or conditional logic","Short document (approximately 250 words)","Only 2 defined/referenced technical terms (time in service, effective date)"],"plain_english_summary":"This safety rule requires operators and maintenance crews of Rolls‑Royce RB211 engines to perform a speed‑governor functional test every 750 flight hours to detect dormant faults that could allow a dangerous engine overspeed. It drops the prior temperature‑governor test (manufacturer says it’s no longer safety‑critical) and updates the referenced Rolls‑Royce service bulletin to the latest revision. CASA enforces the requirement to reduce the risk of engine failure from undetected governor faults."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"Amendment 2 narrows the AD’s obligations by removing the requirement for a periodic test of the temperature governing function while retaining mandatory periodic testing of the speed governing system (Background). The AD continues to apply to the RB211 models listed by the Service Bulletin and keeps the 750‑hour recurring compliance interval (Applicability; Requirement; Compliance)."},"complexity_factors":["Narrow technical scope limited to RB211 series engines listed in the referenced Service Bulletin (Applicability).","Dependence on an external manufacturer Service Bulletin (RB.211‑73‑4305 Rev 6) for procedural detail (Requirement).","Simple, uniform compliance interval (750 hours) and recurring maintenance obligation (Compliance).","A specific change in scope (deletion of temperature-channel periodic test) reduces rather than increases technical complexity (Background).","Reference to another regulator’s mandatory declaration (CAA UK) introduces an inter-jurisdictional linkage but no additional procedural steps (Note)."],"plain_english_summary":"This Airworthiness Directive requires operators of specified Rolls‑Royce RB211 engines to carry out a periodic maintenance test of the speed governing system (see Rolls Royce Service Bulletin RB.211‑73‑4305 Rev 6) to detect dormant failures that might prevent an overspeed response. The amendment removes the previous mandatory periodic test of the temperature governing function (Background). Operators must perform the test within 750 hours time in service and repeat it every 750 hours; operators bear the cost and CASA enforces compliance (Requirement, Compliance)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-rb211-3-amdt-2-speed-and-temperature-governing-system","history":"/api/acts/ad-rb211-3-amdt-2-speed-and-temperature-governing-system/history","analysis":"/api/acts/ad-rb211-3-amdt-2-speed-and-temperature-governing-system/analysis","conflicts":"/api/acts/ad-rb211-3-amdt-2-speed-and-temperature-governing-system/conflicts","importantCases":"/api/acts/ad-rb211-3-amdt-2-speed-and-temperature-governing-system/important-cases","documents":"/api/acts/ad-rb211-3-amdt-2-speed-and-temperature-governing-system/documents"}}