{"id":"F2006B09338","name":"AD/ECUREUIL/3 - Vibration Absorber Mounting Flange - Inspection","slug":"ad-ecureuil-3-vibration-absorber-mounting-flange-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53536,"registerId":"commonwealth-F2006B09338-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/ECUREUIL/3 - Vibration Absorber Mounting Flange - Inspection","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)  Eurocopter AS 350 (Ecureuil) Series Helicopters\n\n \n\n# AD/ECUREUIL/3 Vibration Absorber Mounting Flange - Inspection\n\nApplicability: All models not incorporating modification AMS 350.07.6063. Document:  Aerospatiale AS 350 SB 05.03.\n\n# 8/79\n\nCompliance: Within 25 hours time in service after 4 July 1979 and thereafter at intervals not exceeding 25 hours time in service.\n\n \n\nBackground: Several cracks have been found at the blending radius of the vibration absorber mounting flange installed on the main rotor shaft.\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":2,"scope_assessment":{"changed":false,"description":"The instrument maintains a narrowly targeted scope: it applies to all AS 350 (Ecureuil) helicopters that do not incorporate modification AMS 350.07.6063 and prescribes a recurring inspection interval. There is no indication in the source text that the scope has been expanded or narrowed from its original stated purpose (Applicability; Compliance; Background)."},"complexity_factors":["Narrow applicability: affects only AS 350 helicopters not incorporating modification AMS 350.07.6063 (Applicability).","Simple, fixed compliance interval: inspection within 25 hours after 4 July 1979 and every 25 hours thereafter (Compliance).","Procedural detail delegated to an external service bulletin (Aerospatiale AS 350 SB 05.03), which operators must obtain and follow (Document: Aerospatiale AS 350 SB 05.03).","Operational impact arises from frequency of inspections rather than complicated legal conditions (Compliance).","Potential practical complexity in execution: need for qualified maintenance personnel and possible downtime if defects are found (Background; Compliance)."],"plain_english_summary":"- What this instrument does (mechanical change):\n  - Requires regular visual inspection of the vibration absorber mounting flange on Eurocopter AS 350 (Ecureuil) series helicopters that have not had modification AMS 350.07.6063 fitted. (Applicability; Document: Aerospatiale AS 350 SB 05.03)\n  - The first inspection must be done within 25 hours time in service after 4 July 1979 and then at intervals not exceeding 25 hours time in service thereafter. (Compliance)\n\n- Why it was issued (official rationale):\n  - The AD states that \"several cracks have been found at the blending radius of the vibration absorber mounting flange installed on the main rotor shaft.\" The Aerospatiale service bulletin named in the AD is the referenced procedure for inspection. (Background; Document: Aerospatiale AS 350 SB 05.03)\n\n- Who is affected and who decides:\n  - Affected parties: operators and owners of Eurocopter AS 350 (Ecureuil) helicopters that do not incorporate modification AMS 350.07.6063. (Applicability)\n  - Decision-maker for compliance: the operator (or their maintenance organisation) must schedule and carry out the inspections required by the AD; the Civil Aviation Safety Authority issues the AD and sets the compliance interval. (Applicability; Compliance)\n\n- Who pays and what behaviour changes:\n  - Operators/owners bear the direct costs of performing repeated inspections, any consequential repairs or part replacements, and any downtime while inspections or repairs are carried out. (Compliance)\n  - Operators can avoid repeated inspections for an individual helicopter by fitting modification AMS 350.07.6063; choosing whether to install that modification is a commercial/operational decision for the owner. (Applicability)\n\n- Practical implementation details and compliance mechanics:\n  - The AD points to Aerospatiale AS 350 SB 05.03 for the inspection method; operators must obtain and follow that service bulletin to perform the inspections. (Document: Aerospatiale AS 350 SB 05.03)\n  - Inspections must start within a short window (25 hours TIS after the AD’s effective date) and be repeated frequently (every 25 hours TIS), which requires operators to integrate the checks into routine maintenance scheduling. (Compliance)\n\n- Trade-offs, incentives and risks (source-grounded):\n  - Incentives: Frequent mandated inspections increase maintenance costs but create an incentive to fit modification AMS 350.07.6063 to stop the recurring burden. (Applicability; Compliance)\n  - Compliance burden: The 25-hour inspection interval is frequent relative to many maintenance checks; it may increase labour and scheduling demands on operators and certified maintenance organisations. (Compliance)\n  - Opportunity cost: Time and resources spent on these inspections are not available for other operations or maintenance tasks; if inspections uncover cracks, repair or part replacement will add further downtime and cost. (Background; Compliance)\n  - Implementation risk: The AD requires inspections per the referenced service bulletin; the quality of the inspection depends on access to that bulletin, availability of suitably qualified maintenance personnel, and detection limits of the inspection method. (Document: Aerospatiale AS 350 SB 05.03)\n  - Bureaucratic discretion: The AD prescribes the inspection interval and applicability; the procedural detail is delegated to the referenced Aerospatiale service bulletin, so some implementation detail is supplied by the manufacturer document rather than the AD text itself. (Document: Aerospatiale AS 350 SB 05.03)\n\n- Effects on private enterprise and market responses:\n  - The AD increases short-term operating costs for affected operators via more frequent inspections and potential repairs. (Compliance)\n  - It may raise demand for maintenance labour and parts for the relevant flange or for the modification AMS 350.07.6063, creating concentrated commercial opportunities for maintenance providers and modification suppliers. (Applicability; Background)\n\n- Net practical summary:\n  - If your AS 350 does not have AMS 350.07.6063, you must inspect the vibration absorber mounting flange within 25 hours TIS after 4 July 1979 and then every 25 hours TIS. The rule rests on reported cracking at the flange blending radius and refers operators to Aerospatiale AS 350 SB 05.03 for the inspection procedure. Operators bear the cost and scheduling burden and can avoid repeated inspections by installing the identified modification. (Applicability; Compliance; Background; Document: Aerospatiale AS 350 SB 05.03)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of mandating inspections for cracked vibration absorber mounting flanges."},"complexity_factors":["Extremely short document (approximately 150 words)","Only 1 defined applicability criterion (modification status)","Single compliance requirement with clear time intervals","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1998","No conditional logic or exceptions","Straightforward technical reference to a single Service Bulletin (Aerospatiale AS 350 SB 05.03)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** issued by Australia's Civil Aviation Safety Authority (CASA) for a specific type of helicopter: the **Eurocopter AS 350 (Ecureuil) series**.\n\n**What it does:**\nIt requires helicopter operators to **inspect the vibration absorber mounting flange** on the main rotor shaft for cracks. This is a safety-critical component — if it fails, the helicopter could lose its main rotor.\n\n**Who it affects:**\n- Owners and operators of Eurocopter AS 350 helicopters that **haven't been modified** with a specific fix (modification AMS 350.07.6063)\n- Maintenance engineers responsible for these aircraft\n\n**What must be done:**\n- **First inspection:** Within 25 hours of flying time after 4 July 1979\n- **Ongoing inspections:** Every 25 hours of flying time thereafter\n\n**Why it matters:**\nCracks had been discovered in this part at the \"blending radius\" (the curved transition area where the flange meets the shaft). Without regular inspection, these cracks could grow and cause catastrophic failure of the main rotor system. This AD is a mandatory safety order — compliance is legally required, not optional.\n\n**Key terms explained:**\n- **Airworthiness Directive (AD):** A legally enforceable safety notice requiring specific maintenance or inspections\n- **Time in service:** Actual flying hours, not calendar time\n- **Service Bulletin (SB):** A manufacturer's technical notice referenced here as the inspection procedure source"}},"importantCases":[],"_links":{"self":"/api/acts/ad-ecureuil-3-vibration-absorber-mounting-flange-inspection","history":"/api/acts/ad-ecureuil-3-vibration-absorber-mounting-flange-inspection/history","analysis":"/api/acts/ad-ecureuil-3-vibration-absorber-mounting-flange-inspection/analysis","conflicts":"/api/acts/ad-ecureuil-3-vibration-absorber-mounting-flange-inspection/conflicts","importantCases":"/api/acts/ad-ecureuil-3-vibration-absorber-mounting-flange-inspection/important-cases","documents":"/api/acts/ad-ecureuil-3-vibration-absorber-mounting-flange-inspection/documents"}}