{"id":"F2006B04699","name":"AD/BELL 47/75 Amdt 2 - Control Tubes","slug":"ad-bell-47-75-amdt-2-control-tubes","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44463,"registerId":"commonwealth-F2006B04699-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 47/75 Amdt 2 - Control Tubes","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 47 (All Variants) Series Helicopters\n\n \n\n# AD/BELL 47/75\n\nAmdt 2\n\nApplicability: All models.\n\n# Control Tubes 10/86\n\n \n\nRequirement: 1. Visually inspect the control tubes referenced in Bell SB 47-11-73-1 and Kawasaki- Bell S.B. KSB-Bell 334 for evidence of corrosion pits, particularly in the lower four (4) inches of each tube assembly; or\n\n \n\n2.    Inspect the control tubes referenced in Bell SB 47-11-73-1 and Kawasaki-Bell S.B. KSB-Bell 334 for evidence of corrosion using a suitable radiographic technique; or\n\n \n\n3.    Remove the lower end fittings from the control tubes and visually inspect the internal surface of the tube for evidence of corrosion.\n\n \n\nCompliance: 1. Within 25 hours time in service after 31 December 1973 and thereafter at intervals not exceeding 50 hours time in service.\n\n \n\n2 & 3. Within 25 hours time in service after 31 December 1973 and thereafter at intervals not exceeding 3 years.\n\n \n\nBackground: The manufacturer has received reports of failure of fore and aft control tubes caused by corrosion. This Directive has been amended to include Kawasaki-Bell Helicopters.\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_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":true,"description":"Originally applied only to Bell-manufactured helicopters. Amendment 2 expanded scope to include Kawasaki-Bell licensed production models, broadening geographic and manufacturer coverage while maintaining the same technical safety purpose."},"complexity_factors":["Single, discrete safety requirement with three alternative compliance methods","Only 4 defined terms implicitly used (time in service, control tubes, SB [Service Bulletin], visual inspection)","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1998","Simple conditional logic: three 'or' options for inspection method, with two distinct compliance intervals","No nested exceptions or sub-delegations","Length: approximately 250 words of substantive content"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspections of control tubes on all Bell 47 series helicopters (including Kawasaki‑Bell licensed builds) because corrosion pits near tube ends have caused in‑flight failures. Operators must inspect these tubes regularly — either frequent external checks or periodic internal/radiographic inspections — to prevent control loss. It applies to all Australian owners, operators and maintenance organisations and is legally binding."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"The Background states the Directive \"has been amended to include Kawasaki-Bell Helicopters\", indicating the applicability was expanded beyond Bell-only helicopters to include Kawasaki-Bell units."},"complexity_factors":["Three alternative inspection methods offered, requiring operator choice between visual, radiographic, or disassembly-based inspections","Different compliance intervals depending on chosen method (short short-term interval for initial checks and either 50-hour recurring or 3-year recurring intervals)","Requirement or allowance of radiographic inspection introduces need for specialist equipment or contracted service","Removal of lower end fittings for internal inspection requires mechanical work and potential downtime/parts handling","Applies to all models of the type and was amended to add Kawasaki-Bell—broad applicability increases number of affected operators","Specified initial compliance timing (within 25 hours after 31 December 1973) creates a retroactive action window in the text"],"plain_english_summary":"Requires owners/operators of all Bell Helicopter Textron 47 series helicopters to inspect control tubes for corrosion by one of three methods (external visual check, radiographic inspection, or remove lower end fittings to inspect internally) on set schedules. It affects aircraft operators who must arrange and pay for inspections and any repairs; the action follows manufacturer reports of control-tube failures caused by corrosion."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-47-75-amdt-2-control-tubes","history":"/api/acts/ad-bell-47-75-amdt-2-control-tubes/history","analysis":"/api/acts/ad-bell-47-75-amdt-2-control-tubes/analysis","conflicts":"/api/acts/ad-bell-47-75-amdt-2-control-tubes/conflicts","importantCases":"/api/acts/ad-bell-47-75-amdt-2-control-tubes/important-cases","documents":"/api/acts/ad-bell-47-75-amdt-2-control-tubes/documents"}}