{"id":"F2006B06329","name":"AD/PR/3 - Pitch Lock Support Sleeve - Modification","slug":"ad-pr-3-pitch-lock-support-sleeve-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47492,"registerId":"commonwealth-F2006B06329-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PR/3 - Pitch Lock Support Sleeve - 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/3 Pitch Lock Support Sleeve - Modification NK\n\nApplicability: All model R193/4/-30-4/50 installed on Fokker F27; R184/4-30-4/50 installed on Grumman G159; and R179/4-20-4/33 installed on Viscount 810.\n\nDocument: Dowty Rotol SB No. 61-185 (Mod. No. (c) VP 2032), Rev. 4. Compliance:  Before installation in an aircraft following next overhaul completed after\n\n28 February 1966.\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 vintage Airworthiness Directive from 1966 (compliance deadline references February 1966). It remains a narrow, targeted safety order addressing a specific mechanical defect in specific propeller models. No scope creep is evident; it has not expanded beyond its original technical purpose."},"complexity_factors":["Single, specific technical modification with clear applicability","Only 3 aircraft types and 3 propeller models affected","Single compliance pathway (modification at next overhaul post-28 Feb 1966)","References only one external technical document (Dowty Rotol SB 61-185)","No nested exceptions, conditional logic, or defined terms section","Extremely short — approximately 100 words of substantive content"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires a specific mechanical modification to certain aircraft propellers to keep them airworthy.\n\n**What it does:**\n- Orders owners and operators to modify the \"pitch lock support sleeve\" on specific Dowty Rotol propeller models\n- The modification prevents the propeller from failing to maintain proper blade angle (pitch), which could cause loss of thrust or engine damage\n\n**Who it affects:**\n- Operators of three specific aircraft types:\n  - **Fokker F27** (with R193/4/-30-4/50 propellers)\n  - **Grumman G159** (with R184/4-30-4/50 propellers)  \n  - **Vickers Viscount 810** (with R179/4-20-4/33 propellers)\n\n**What must be done:**\n- Install a modified support sleeve per Dowty Rotol Service Bulletin No. 61-185 (Modification VP 2032), Revision 4\n- **Deadline:** Before installing the propeller in an aircraft, following the next overhaul completed after 28 February 1966\n\n**Why it matters:**\nAirworthiness Directives are legally binding. Non-compliance grounds the aircraft — it cannot fly until fixed. This particular AD addresses a known defect in the propeller's pitch-locking mechanism that could compromise flight safety."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive’s scope remains limited to the specified propeller models installed on the listed aircraft types and requires the pitch lock support sleeve modification per the cited Dowty Rotol service bulletin prior to installation after the next overhaul completed after 28 February 1966. There is no indication in the text that the applicability or required modification was expanded beyond those stated models, aircraft or the single referenced service bulletin."},"complexity_factors":["Narrow technical scope limited to three specific propeller models and three aircraft types (low breadth). (Applicability)","Dependence on an external technical document (Dowty Rotol SB No. 61-185 Rev. 4) for procedural detail increases practical complexity. (Document)","Compliance timing is tied to the event of \"next overhaul completed after 28 February 1966,\" which is an event-driven trigger that operators must track for each unit. (Compliance)","Vintage date and potential obsolescence of the directive or referenced SB could create ambiguity in implementation and parts availability.","Regulatory enforcement requires coordination between operators, approved maintenance organisations and the Civil Aviation Safety Authority, introducing administrative tasks (recording, sign-off, oversight)."],"plain_english_summary":"This directive requires a specific modification to the pitch‑lock support sleeve of certain Dowty Rotol variable‑pitch propellers (per Service Bulletin No. 61‑185, Rev.4) for listed Fokker F27, Grumman G159 and Viscount 810 installations. Affected owners/operators and maintenance organisations must complete the modification before re‑installation after the next overhaul completed after 28 Feb 1966; operators bear costs and CASA enforces compliance."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pr-3-pitch-lock-support-sleeve-modification","history":"/api/acts/ad-pr-3-pitch-lock-support-sleeve-modification/history","analysis":"/api/acts/ad-pr-3-pitch-lock-support-sleeve-modification/analysis","conflicts":"/api/acts/ad-pr-3-pitch-lock-support-sleeve-modification/conflicts","importantCases":"/api/acts/ad-pr-3-pitch-lock-support-sleeve-modification/important-cases","documents":"/api/acts/ad-pr-3-pitch-lock-support-sleeve-modification/documents"}}