{"id":"F2006B06311","name":"AD/PR/13 - Pitch Lock Assembly - Modification","slug":"ad-pr-13-pitch-lock-assembly-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47433,"registerId":"commonwealth-F2006B06311-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PR/13 - Pitch Lock Assembly - Modification","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/13 Pitch Lock Assembly - Modification NK\n\nApplicability: All model (c) R184/4-30-4/50 (Gulfstream) and model (c) R193/4-30-4/50 and -4/61 (Fokker F.27).\n\n \n\nDocument: Dowty Rotol SB No. 61-764, Rev. 1. (Mod. No. (c) VP 2774).\n\n \n\nCompliance: Before installation in an aircraft following next overhaul completed after 30 June 1971.\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":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1628},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This airworthiness directive maintains its original narrow, safety-focused scope: mandating a specific mechanical modification to pitch lock assemblies on defined propeller models. There is no indication of expansion beyond the initial intent to address a specific airworthiness concern with these Dowty Rotol propellers."},"complexity_factors":["Single, specific technical requirement limited to two aircraft types and specific propeller model numbers","Reference to external technical document (Service Bulletin 61-764) for implementation details","Straightforward compliance condition tied to maintenance overhaul schedule rather than calendar date alone","No nested exceptions, defined terms, or conditional logic within the directive text itself"],"plain_english_summary":"**What this is:** A mandatory safety directive (called an Airworthiness Directive) that requires a specific mechanical fix for certain aircraft propellers to ensure they remain safe to operate.\n\n**Who it affects:** Operators of **Gulfstream** and **Fokker F.27** aircraft fitted with specific Dowty Rotol propeller models (R184/4-30-4/50 and R193/4-30-4/50 or -4/61).\n\n**What it requires:** You must modify the **pitch lock assembly** — a critical component that prevents propeller blades from changing pitch angle unexpectedly — following the technical instructions in the manufacturer's Service Bulletin No. 61-764 (Modification VP 2774).\n\n**When to comply:** The modification must be completed before installing the propeller on an aircraft, specifically during the first overhaul completed after 30 June 1971.\n\n**Why this matters:** Pitch lock assemblies are essential for flight safety. This directive ensures these specific propeller designs meet updated safety standards to prevent potential mechanical failures that could affect aircraft control or cause loss of thrust."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pr-13-pitch-lock-assembly-modification","history":"/api/acts/ad-pr-13-pitch-lock-assembly-modification/history","analysis":"/api/acts/ad-pr-13-pitch-lock-assembly-modification/analysis","conflicts":"/api/acts/ad-pr-13-pitch-lock-assembly-modification/conflicts","importantCases":"/api/acts/ad-pr-13-pitch-lock-assembly-modification/important-cases","documents":"/api/acts/ad-pr-13-pitch-lock-assembly-modification/documents"}}