{"id":"F2006B06320","name":"AD/PR/21 - Hub Assembly - Inspection of Blade Sockets","slug":"ad-pr-21-hub-assembly-inspection-of-blade-sockets","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47462,"registerId":"commonwealth-F2006B06320-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PR/21 - Hub Assembly - Inspection of Blade Sockets","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/21 Hub Assembly - Inspection of Blade Sockets NK\n\nApplicability: All model (c) R212/4-30-4/22/1 propellers (Argosy 222), not modified in accordance with Mod. VP 2388.\n\n \n\nRequirement: With the aid of a 3X magnifying glass, visually inspect for cracks the complete accessible exterior surface of the hub P/N RA60600, paying particular attention to the areas between the blade sockets, and the rear half circumference of the sockets.\n\n \n\nCompliance: Within 25 hours time in service after 1 November 1978.\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":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1805},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive maintains its original narrow scope: a targeted safety inspection for cracks in a specific propeller hub design. No evidence of scope expansion beyond the original airworthiness safety intent."},"complexity_factors":["Single, straightforward inspection requirement with no sub-conditions","Limited applicability (specific propeller model and modification status)","Simple compliance deadline based on flight hours","Minimal technical jargon beyond necessary part numbers"],"plain_english_summary":"**What this does:** Orders a one-time safety inspection of specific aircraft propellers to find dangerous cracks in the hub assembly.\n\n**Who it affects:** Operators of Argosy 222 aircraft using Dowty Rotol propellers (model R212/4-30-4/22/1) that have **not** been modified according to Mod. VP 2388.\n\n**What you must do:** Using a basic magnifying glass (3X magnification), visually check the entire outside surface of the hub part (P/N RA60600) for cracks. Pay special attention to two high-risk areas:\n- The spaces between the blade sockets\n- The rear half of the socket circumferences\n\n**Deadline:** Complete the inspection within 25 hours of flight time after 1 November 1978.\n\n**Why it matters:** Fatigue cracks in propeller hubs can cause the propeller to fail during flight. This simple visual check catches structural damage before it becomes catastrophic."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pr-21-hub-assembly-inspection-of-blade-sockets","history":"/api/acts/ad-pr-21-hub-assembly-inspection-of-blade-sockets/history","analysis":"/api/acts/ad-pr-21-hub-assembly-inspection-of-blade-sockets/analysis","conflicts":"/api/acts/ad-pr-21-hub-assembly-inspection-of-blade-sockets/conflicts","importantCases":"/api/acts/ad-pr-21-hub-assembly-inspection-of-blade-sockets/important-cases","documents":"/api/acts/ad-pr-21-hub-assembly-inspection-of-blade-sockets/documents"}}