{"id":"F2009L03112","name":"AD/BO 105/28 - Tail Rotor Balance Weights","slug":"ad-bo-105-28-tail-rotor-balance-weights","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":80828,"registerId":"commonwealth-F2009L03112-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Eurocopter BO 105 Series Helicopters","sectionType":"division","heading":"Eurocopter BO 105 Series Helicopters","content":"### Eurocopter BO 105 Series Helicopters\n\n| AD/BO 105/28 | Tail Rotor Balance Weights | 9/2009 |\n| ------------ | -------------------------- | ------ |\n\n| Applicability: | Eurocopter Canada BO 105 LS A-3 helicopters.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Perform the initial and repeat inspections of the tail rotor balance weights and control levers in accordance with the accomplishment instructions of Eurocopter Canada Alert Service Bulletin (ASB) BO 105 LS 30-12, dated 12 December 2008, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.2. If, as a result of the inspections above, the detected damage exceeds the acceptable limits specified in ASB BO 105 LS 30-12; replace the affected parts with serviceable parts. Replacement of parts does not constitute terminating action for the repetitive inspection requirements of this directive.Note: Transport Canada AD CF-2009-12 dated 24 March 2009 refers. |\n| Compliance:    | For Requirement 1 - Initially, within the next 2 months or 100 flight hours, whichever occurs first after the effective date of this AD, unless already accomplished.Thereafter at intervals not exceeding 600 flight hours or 48 months, whichever occurs first.For Requirement 2 - Before further flight.                                                                                                                                                                                                                                                                                                                                                                                                         |\n|                | This Airworthiness Directive becomes effective on 27 August 2009.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |\n| Background:    | During a periodical inspection, corrosion was detected on the tail rotor balance weights in the area of the attachment thread.This condition, if not corrected, could lead to balance weight separation from the tail rotor, resulting in severe vibration and consequent loss of control of the helicopter.                                                                                                                                                                                                                                                                                                                                                                                                        |\n\n![](image.001.png)  \nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n15 July 2009","sortOrder":0},{"sectionNumber":"AD/BO 105/28","sectionType":"part","heading":"AD/BO 105/28","content":"## AD/BO 105/28","sortOrder":1},{"sectionNumber":"Tail Rotor Balance Weights","sectionType":"part","heading":"Tail Rotor Balance Weights","content":"## Tail Rotor Balance Weights","sortOrder":2},{"sectionNumber":"9/2009","sectionType":"part","heading":"9/2009","content":"## 9/2009","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive remains focused on corrosion detection and mitigation for tail rotor balance weights and control levers on BO 105 LS A‑3 helicopters. It does not expand applicability beyond that model or add additional types of corrective action; obligations are limited to inspections per the specified ASB and replacement when damage exceeds stated limits."},"complexity_factors":["Narrow applicability: applies only to Eurocopter Canada BO 105 LS A‑3 helicopters (limits stakeholder scope).","Two-tier compliance timing: initial action within 2 months or 100 flight hours, then recurring at 600 flight hours or 48 months (either/or framing adds scheduling detail).","Mandatory adherence to an external document: inspections must follow Eurocopter ASB BO 105 LS 30‑12 or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada (delegates substantive technical detail to ASB and regulator approvals).","Non‑terminating remedial action: replacing parts does not remove the requirement for future inspections (creates ongoing recurring cost).","Immediate safety imperative: detected excessive damage requires replacement before further flight (zero discretion on deferral when limits exceeded).","Referenced foreign regulator action: note refers to Transport Canada AD CF‑2009‑12 (cross‑jurisdictional referencing can complicate interpretation).","Operational burden concentrated on operators: inspections, recordkeeping and parts procurement are borne by helicopter owners/operators."],"plain_english_summary":"**What it does:** Requires operators of Eurocopter Canada BO 105 LS A‑3 helicopters to inspect tail‑rotor balance weights and control levers per Eurocopter ASB BO 105 LS 30‑12, initially within 2 months or 100 flight hours and then every 600 flight hours or 48 months, and to replace parts that exceed damage limits before further flight. **Why it matters:** Transport Canada says the inspections prevent corrosion-related weight separation that could cause severe vibration and loss of control. Operators bear inspection and replacement costs; replacements do not end the recurring inspection duty."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard Airworthiness Directive with focused, original scope. It addresses a specific safety defect in a specific helicopter model without expansion into broader regulatory areas."},"complexity_factors":["Single, specific aircraft model affected (Eurocopter BO 105 LS A-3)","Only 2 main requirements with clear conditional logic (inspect; replace if damaged)","Simple compliance timeline (initial + recurring intervals)","No defined terms section or complex interpretation provisions","Minimal cross-referencing (only references one service bulletin and one Canadian AD)","Straightforward cause-and-effect safety rationale","Document appears to be a formatted directive with redundant headers rather than complex legislative text"],"plain_english_summary":"This CASA Airworthiness Directive requires Australian owners/operators of Eurocopter BO 105 LS A‑3 helicopters to inspect (and, if needed, replace) tail rotor balance weights and control levers because corrosion can cause weights to detach, leading to violent vibration and loss of control.  \n\nInspections must start within 2 months or 100 flight hours from 27 Aug 2009 and repeat every 600 flight hours or 4 years; damaged parts must be replaced before further flight. Compliance is mandatory."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-bo-105-28-tail-rotor-balance-weights","history":"/api/acts/ad-bo-105-28-tail-rotor-balance-weights/history","analysis":"/api/acts/ad-bo-105-28-tail-rotor-balance-weights/analysis","conflicts":"/api/acts/ad-bo-105-28-tail-rotor-balance-weights/conflicts","importantCases":"/api/acts/ad-bo-105-28-tail-rotor-balance-weights/important-cases","documents":"/api/acts/ad-bo-105-28-tail-rotor-balance-weights/documents"}}