{"id":"F2006B04319","name":"AD/BELL 204/11 - Servo Cylinder Upper Control Tube Fittings - Inspections","slug":"ad-bell-204-11-servo-cylinder-upper-control-tube-fittings-inspections","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44134,"registerId":"commonwealth-F2006B04319-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 204/11 - Servo Cylinder Upper Control Tube Fittings - Inspections","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 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Bell Helicopter Textron 204 Series Helicopters\n\n \n\nAD/BELL 204/11 Servo Cylinder Upper Control NK\n\nTube Fittings - Inspections\n\n \n\nApplicability: All model 204B. Document: Bell SL No. 204B-87.\n\nCompliance: Within 100 hours’ time in service after 31 May 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","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The text as provided clearly states the scope: it applies to all Bell model 204B helicopters and mandates inspection of the servo cylinder upper control tube fittings within the stated time window. The document does not indicate any alteration to that stated scope."},"complexity_factors":["Narrow applicability: applies only to Bell model 204B (Applicability).","Single, time‑limited action: one inspection requirement with a specific compliance window (Compliance).","Procedural detail omitted: inspection steps are delegated to an external manufacturer document (Bell SL No. 204B-87), creating reliance on that document for implementation (Document).","Ambiguity on recurrence: the AD text does not specify whether inspections are one‑off or recurring, which may require consultation of the service letter or regulator guidance (Compliance; Document).","Dated compliance deadline: the compliance window is tied to a historical date (31 May 1971), which may raise record‑keeping or applicability questions for airworthiness records (Compliance)."],"plain_english_summary":"This Airworthiness Directive mandates inspection of the servo cylinder upper control tube fittings on all Bell model 204B helicopters, to be completed within 100 hours’ time in service after 31 May 1971. Operators/owners must obtain and follow Bell Service Letter No. 204B‑87, pay for inspections and any repairs, and absorb downtime; the AD gives the compliance window but delegates procedural detail to the service letter and does not state whether inspections recur."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive issued in 1971. It has not expanded beyond its original narrow purpose of addressing a specific mechanical inspection on one helicopter model. The scope remains tightly constrained to the servo cylinder upper control tube fittings inspection requirement."},"complexity_factors":["Extremely short document — only 4 substantive lines of regulatory text","No defined terms section — relies entirely on external reference (Bell SL No. 204B-87)","Single, clear compliance requirement with unambiguous deadline","No cross-references to other legislation beyond the enabling Civil Aviation Regulations 1998","No conditional logic, exceptions, or nested provisions","Simple applicability test (model 204B only)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:**\nOrders owners and operators of **Bell 204B helicopters** to inspect the **servo cylinder upper control tube fittings** — these are mechanical parts that help control the helicopter's flight surfaces.\n\n**Who it affects:**\nAnyone who owns or operates a **Bell Helicopter Textron 204 Series** (specifically model 204B) in Australia.\n\n**What must be done:**\nOperators must complete the inspection described in **Bell Service Letter No. 204B-87** within **100 hours of flight time** after **31 May 1971**.\n\n**Why it matters:**\nAirworthiness Directives are legally binding safety instructions. If you don't comply, you cannot legally fly the aircraft. This particular AD addresses a specific mechanical component that, if it fails, could affect flight control and safety. The reference to 1971 indicates this is a historical directive for an older aircraft type still in service."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-204-11-servo-cylinder-upper-control-tube-fittings-inspections","history":"/api/acts/ad-bell-204-11-servo-cylinder-upper-control-tube-fittings-inspections/history","analysis":"/api/acts/ad-bell-204-11-servo-cylinder-upper-control-tube-fittings-inspections/analysis","conflicts":"/api/acts/ad-bell-204-11-servo-cylinder-upper-control-tube-fittings-inspections/conflicts","importantCases":"/api/acts/ad-bell-204-11-servo-cylinder-upper-control-tube-fittings-inspections/important-cases","documents":"/api/acts/ad-bell-204-11-servo-cylinder-upper-control-tube-fittings-inspections/documents"}}