{"id":"F2006B06750","name":"AD/S-76/9 - Cyclic Torque Tube - Inspection of Centre Support Bearing Housing","slug":"ad-s-76-9-cyclic-torque-tube-inspection-of-centre-support-bearing-housing","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114577,"registerId":"commonwealth-F2006B06750-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/S-76/9 - Cyclic Torque Tube - Inspection of Centre Support Bearing Housing","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)  Sikorsky S-76 Series Helicopters\n\n \n\nAD/S-76/9 Cyclic Torque Tube - Inspection of Centre Support Bearing Housing\n\n\n3/80\n\n \n\nApplicability: Model S-76. Document: Sikorsky CSB 76-67-7.\n\nCompliance: Within 10 hours time in service after 14 February 1980.\n\n \n\nBackground: Some bearing support housings have been incorrectly manufactured, with the bearing retaining shoulder on the wrong side. This would permit axial displacement of the bearing along the torque tube.\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":{"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The directive's scope is limited to inspection of the centre support bearing housing on Model S-76 helicopters to address a specific manufacturing defect (bearing retaining shoulder on wrong side). The text sets the same applicability and mandatory inspection timing and points users to Sikorsky CSB 76-67-7 for the inspection procedure. There is no indication in the provided text that the scope has been altered from that stated intent. (Applicability; Compliance; Background; Document: Sikorsky CSB 76-67-7)"},"complexity_factors":["Narrow and specific technical scope (single component on a single helicopter model). (Applicability)","Short, urgent compliance window (10 hours TIS) concentrates operational impact. (Compliance)","Technical inspection procedure is not detailed in the text and is delegated to an external manufacturer document (Sikorsky CSB 76-67-7), requiring users to obtain and follow that document. (Document: Sikorsky CSB 76-67-7)","Safety-critical mechanical consequence (axial displacement of bearing) requires competent maintenance personnel and potentially parts replacement. (Background)","Legal mandate (airworthiness directive) leaves little operator discretion on timing; practical scheduling and grounding costs fall to operators. (COMMONWEALTH OF AUSTRALIA... SCHEDULE OF AIRWORTHINESS DIRECTIVES; Compliance)"],"plain_english_summary":"This AD mandates owners/operators of Sikorsky S‑76 helicopters to inspect the cyclic torque tube’s centre support bearing housing (follow Sikorsky CSB 76‑67‑7) within 10 hours TIS after 14 Feb 1980. It was issued because some housings were made with the bearing‑retaining shoulder on the wrong side, risking axial bearing displacement. Operators bear inspection and any repair costs and must schedule urgent maintenance."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive from 1980 addressing a specific manufacturing defect in one helicopter model. It has not expanded beyond its original narrow safety purpose."},"complexity_factors":["Single, specific mechanical defect addressed","Only one compliance action required (visual/physical inspection)","No defined terms section — uses plain technical language","Single cross-reference to manufacturer service bulletin (CSB 76-67-7)","No conditional logic, exceptions, or nested provisions","Extremely short — approximately 100 words of substantive content","Clear, fixed compliance deadline (10 hours TIS after 14 Feb 1980)"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft operators.\n\n**What it does:**\nOrders owners and operators of **Sikorsky S-76 helicopters** to inspect a specific part called the \"cyclic torque tube centre support bearing housing.\" This component helps control the helicopter's rotor system.\n\n**The problem:**\nSome of these bearing housings were manufactured incorrectly — the shoulder that holds the bearing in place was put on the wrong side. This defect could allow the bearing to slide along the torque tube (axial displacement), potentially causing loss of control.\n\n**Who must comply:**\nAnyone operating Model S-76 helicopters in Australia.\n\n**What they must do:**\nInspect the part within **10 hours of flight time** after 14 February 1980, following the procedure in Sikorsky's service bulletin CSB 76-67-7.\n\n**Why it matters:**\nThis is a critical safety fix. A failed bearing in the flight control system could lead to catastrophic loss of control. The directive makes compliance mandatory — operators cannot legally fly the aircraft until the inspection is done."}},"importantCases":[],"_links":{"self":"/api/acts/ad-s-76-9-cyclic-torque-tube-inspection-of-centre-support-bearing-housing","history":"/api/acts/ad-s-76-9-cyclic-torque-tube-inspection-of-centre-support-bearing-housing/history","analysis":"/api/acts/ad-s-76-9-cyclic-torque-tube-inspection-of-centre-support-bearing-housing/analysis","conflicts":"/api/acts/ad-s-76-9-cyclic-torque-tube-inspection-of-centre-support-bearing-housing/conflicts","importantCases":"/api/acts/ad-s-76-9-cyclic-torque-tube-inspection-of-centre-support-bearing-housing/important-cases","documents":"/api/acts/ad-s-76-9-cyclic-torque-tube-inspection-of-centre-support-bearing-housing/documents"}}