{"id":"F2006B04696","name":"AD/BELL 47/68 - Control Tubes","slug":"ad-bell-47-68-control-tubes","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44460,"registerId":"commonwealth-F2006B04696-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 47/68 - 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\nAD/BELL 47/68 Control Tubes 9/71\n\nApplicability: All models fitted with Control Tubes P/N 47-150-255-1. Document:  Bell SB 47-146.\n\nCompliance: Within 100 hours time in service or 30 days after 29 October 1971 whichever occurs first and thereafter at intervals not exceeding 1200 hours time in service.\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 discrete, original airworthiness directive from 1971. It has not expanded beyond its original purpose of addressing a specific control tube defect in Bell 47 helicopters. The scope remains tightly confined to the original safety issue."},"complexity_factors":["Single, specific technical requirement (one part number)","Clear, binary applicability test (fitted with P/N 47-150-255-1 or not)","Simple compliance timeline (initial deadline + recurring interval)","No defined terms section, no cross-references to other legislation","Only 4 operative paragraphs (Applicability, Document reference, Compliance)","No conditional logic, exceptions, or nested provisions"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nOrders owners and operators of certain Bell 47 helicopters to inspect or replace specific control tubes (part number 47-150-255-1) that steer the aircraft. These tubes are critical flight controls — if they fail, the pilot could lose control of the helicopter.\n\n**Who it affects:**\nAnyone operating a Bell 47 helicopter (any variant) that has these specific control tubes installed.\n\n**What must be done:**\n- **First check:** Within 100 flight hours OR 30 days after 29 October 1971 — whichever comes first\n- **Ongoing checks:** Every 1,200 flight hours after that\n\n**Why it matters:**\nThis directive addresses a known safety defect identified by the manufacturer (Bell Helicopter) in Service Bulletin 47-146. Without compliance, the control tubes could fail in flight, risking catastrophic loss of control. This is not optional — it's legally enforceable under the Civil Aviation Regulations 1998."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD's scope is confined to Bell 47-series helicopters fitted with Control Tubes P/N 47-150-255-1 and to compliance with Bell SB 47-146 at the specified initial and recurring intervals. The instrument itself does not expand or narrow that applicability beyond the part-number limitation and the stated compliance schedule (Applicability; Document; Compliance)."},"complexity_factors":["Narrow and specific applicability (only helicopters fitted with Control Tubes P/N 47-150-255-1). (Applicability.)","Clear, simple timing rules for initial compliance and recurring intervals (100 hours or 30 days initial; 1,200 hours recurring). (Compliance.)","Requires follow-up on an external technical document (Bell SB 47-146) for procedural detail, so the AD itself does not contain full work instructions. (Document.)","Historic fixed date reference (30 days after 29 October 1971) creates a temporal anchor for initial compliance in the text.","Enforcement and any further administrative discretion are handled through the airworthiness-directive process rather than in the AD text, requiring cross-reference to regulator practice. (PART 39 - 105; Schedule of Airworthiness Directives.)"],"plain_english_summary":"This directive mandates that Bell 47-series helicopters fitted with Control Tube P/N 47-150-255-1 comply with the tasks in Bell Service Bulletin 47-146, first within 100 flight hours or 30 days after 29 Oct 1971 (whichever is sooner) and thereafter at intervals not exceeding 1,200 hours. It affects owners/operators and maintenance organisations, who bear the cost, must access SB 47-146, and schedule the required initial and recurring work."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-47-68-control-tubes","history":"/api/acts/ad-bell-47-68-control-tubes/history","analysis":"/api/acts/ad-bell-47-68-control-tubes/analysis","conflicts":"/api/acts/ad-bell-47-68-control-tubes/conflicts","importantCases":"/api/acts/ad-bell-47-68-control-tubes/important-cases","documents":"/api/acts/ad-bell-47-68-control-tubes/documents"}}