{"id":"F2006B06337","name":"AD/PR/9 - Hub Driving Centre - Inspection","slug":"ad-pr-9-hub-driving-centre-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47519,"registerId":"commonwealth-F2006B06337-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PR/9 - Hub Driving Centre - Inspection","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 - 107 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Propellers - Variable Pitch - Dowty Rotol\n\n \n\nAD/PR/9  Hub Driving Centre - Inspection NK Applicability:  All model (c) R184/4-30-4/50 propellers not incorporating Mod. No. (c) VP 2486. Document:              Dowty Rotol SB No. 61-633.\n\nCompliance:  Before exceeding 2500 hours total time in service and thereafter at intervals not exceeding 750 hours time in service.\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\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 focused on a specific known defect in a specific propeller model. It has not expanded beyond its original purpose of preventing hub driving centre failures."},"complexity_factors":["Single, specific mechanical component targeted (hub driving centre)","Clear, binary applicability test (specific model AND absence of specific modification)","Simple compliance schedule (one-time threshold + fixed interval)","No defined terms section, no cross-references to other legislation","No conditional exceptions or nested logic","References external technical document (Service Bulletin) for detailed procedures rather than embedding them"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:**\nIt requires owners and operators of specific aircraft propellers to inspect the \"hub driving centre\" (a critical component that connects the propeller blades to the engine) for cracks or damage.\n\n**Who it affects:**\nAnyone operating aircraft with **Dowty Rotol model R184/4-30-4/50 variable-pitch propellers** that have **not** been modified with \"Mod. No. VP 2486\".\n\n**What must be done:**\n- **First inspection:** Before the propeller reaches 2,500 total flight hours\n- **Repeat inspections:** Every 750 flight hours thereafter\n\n**Why it matters:**\nHub driving centre failures can cause catastrophic propeller detachment or loss of control. This AD prevents accidents by catching fatigue cracks before they cause failure. The directive references a Dowty Rotol Service Bulletin (SB 61-633) which contains the detailed inspection instructions.\n\n**Key terms explained:**\n- **Variable pitch propeller:** A propeller whose blade angles can be adjusted in flight to optimise performance\n- **Time in service:** Actual flight hours (not calendar time)\n- **Service Bulletin:** A manufacturer's technical notice recommending maintenance actions"},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The source text is a standalone airworthiness directive that sets applicability, an exclusion, the required inspection procedure reference, and explicit time-in-service intervals. It does not indicate any change in scope from an earlier instrument or a prior version; no information in the text shows that the directive expands or restricts a previously stated scope."},"complexity_factors":["Narrow technical scope: applies to a single propeller model and a single component (hub driving centre) (Applicability).","Clear, prescriptive compliance schedule: one initial threshold and a fixed recurring interval (Compliance).","Exclusion clause: reference to Mod. No. (c) VP 2486 creates a binary applicability condition (Applicability).","Dependence on an external document for procedural detail: Dowty Rotol SB No. 61-633 must be consulted for the actual inspection steps (Document).","Operational impacts: recurrent inspections imply scheduling, downtime and potential repairs that operators must manage (Compliance)."],"plain_english_summary":"This airworthiness directive mandates a physical inspection of the hub driving centre on Dowty Rotol model (c) R184/4-30-4/50 propellers (unless Mod. No. (c) VP 2486 is fitted), using Dowty Rotol Service Bulletin No. 61-633. Owners/operators must inspect before the propeller exceeds 2,500 hours TIS and repeat at intervals not over 750 hours. Compliance and inspection costs fall to operators, who may fit the excluded modification to avoid the recurring requirement."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pr-9-hub-driving-centre-inspection","history":"/api/acts/ad-pr-9-hub-driving-centre-inspection/history","analysis":"/api/acts/ad-pr-9-hub-driving-centre-inspection/analysis","conflicts":"/api/acts/ad-pr-9-hub-driving-centre-inspection/conflicts","importantCases":"/api/acts/ad-pr-9-hub-driving-centre-inspection/important-cases","documents":"/api/acts/ad-pr-9-hub-driving-centre-inspection/documents"}}