{"id":"F2006B06569","name":"AD/RB211/9 - Fan Cowl Support Strut Stowage","slug":"ad-rb211-9-fan-cowl-support-strut-stowage","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":48335,"registerId":"commonwealth-F2006B06569-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/RB211/9 - Fan Cowl Support Strut Stowage","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/RB211/9 Fan Cowl Support Strut Stowage 7/86\n\nApplicability: RB211-524 series engines.\n\n \n\nRequirement: Modify the fan cowl support strut mechanism in accordance with Rolls Royce S.B. RB 211-71-7254 Rev 1.\n\n \n\nReference Document FAA AD 86-07-03 Amdt 39-5276.\n\n \n\nCompliance: Prior to 31 July 1987.\n\n \n\nBackground: This Directive is issued to require modification of the left rear fan cowl door support stowage mechanism. The modification is required to prevent an unrestrained cowl support jamming the throttle control linkages.\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, single-issue safety directive focused on one specific mechanical defect. It has not expanded beyond its original purpose of preventing throttle linkage jamming on a specific engine model."},"complexity_factors":["Single, specific mechanical modification required","Only one defined applicability criterion (RB211-524 series engines)","No nested exceptions or conditional logic","Clear compliance deadline (single date)","References only one external technical document","Extremely short — approximately 100 words of substantive content"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). Think of it like a recall notice for aircraft, but legally binding.\n\n**What it does:** It requires owners or operators of specific Rolls-Royce jet engines (the RB211-524 series) to modify a mechanical part called the \"fan cowl support strut.\" This is a bracket that holds the engine's protective cover (the cowl) when it's opened for maintenance.\n\n**Why it matters:** Without this fix, the support strut could come loose and jam the throttle control linkages — the cables or rods that control engine power. If that happens during flight, the crew might lose the ability to adjust engine thrust, which is obviously extremely dangerous.\n\n**Who must comply:** Anyone operating aircraft with RB211-524 engines (commonly used on Boeing 747s and similar large aircraft) had to complete this modification before 31 July 1987.\n\n**How to comply:** Follow the technical instructions in Rolls-Royce Service Bulletin RB 211-71-7254 Revision 1."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The instrument's scope is confined to RB211‑524 series engines and requires a specific modification per a named service bulletin with a fixed compliance date (Applicability, Requirement, Compliance). The text provided shows no expansion or narrowing of that scope beyond these elements, so there is no evidence in the supplied text that the scope has changed from its apparent original intent."},"complexity_factors":["Narrow applicability limited to RB211‑524 series engines (Applicability).","Single, clearly‑specified technical action: modify fan cowl support stowage mechanism per a named service bulletin (Requirement).","Dependency on an external technical document (Rolls Royce S.B. RB 211‑71‑7254 Rev 1) for implementation details (Requirement).","Fixed compliance deadline with no alternatives or exemptions set out in the text (Compliance).","Limited procedural detail in the AD itself (no cost allocation, no alternative compliance paths) increases reliance on implementers and the service bulletin for specifics (Requirement, Compliance)."],"plain_english_summary":"This AD mandates a physical modification to the fan cowl support stowage on Rolls‑Royce RB211‑524 engines, performed per Rolls‑Royce Service Bulletin RB 211‑71‑7254 Rev 1, to prevent an unrestrained fan cowl support from jamming throttle control linkages.  \n\nIt affects engine owners, operators and maintenance organisations, must be completed by 31 July 1987, and will entail parts, labour and downtime under the specified service bulletin."}},"importantCases":[],"_links":{"self":"/api/acts/ad-rb211-9-fan-cowl-support-strut-stowage","history":"/api/acts/ad-rb211-9-fan-cowl-support-strut-stowage/history","analysis":"/api/acts/ad-rb211-9-fan-cowl-support-strut-stowage/analysis","conflicts":"/api/acts/ad-rb211-9-fan-cowl-support-strut-stowage/conflicts","importantCases":"/api/acts/ad-rb211-9-fan-cowl-support-strut-stowage/important-cases","documents":"/api/acts/ad-rb211-9-fan-cowl-support-strut-stowage/documents"}}