{"id":"F2006B08728","name":"AD/DAUPHIN/17 - Hydraulic System","slug":"ad-dauphin-17-hydraulic-system","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":51956,"registerId":"commonwealth-F2006B08728-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DAUPHIN/17 - Hydraulic System","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 SA 360 and SA 365 (Dauphin) Series Helicopters\n\n \n\nAD/DAUPHIN/17 Hydraulic System  1/87 DM\n\n \n\nApplicability: All Model SA360C, SA365C, C1, C2 and C3 helicopters.\n\n \n\nRequirement: Action in accordance with Aerospatiale SA360 and 365 Service Bulletin No. 29-01.\n\n \n\nNote: French AD 86-176-27(B) refers.\n\n \n\nCompliance: Before further flight after 31 December 1986.\n\n \n\nFor spares: before installation in an aircraft after 31 December 1986.\n\n \n\nBackground: A spring spacer is fitted to prevent an overpressure in the hydraulic systems if the flange of the regulator valve stem should come off.\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 directive's scope is consistent with its stated purpose: it applies to the listed SA360/SA365 models and extends the requirement to spares, mandating the fitting of a spring spacer to prevent hydraulic overpressure (Applicability; Requirement; For spares; Background). There is no indication in the text that the scope has been expanded or narrowed from that stated intent."},"complexity_factors":["Narrow and specific applicability to a small set of helicopter models (Applicability).","Single, discrete technical requirement tied to a manufacturer Service Bulletin (Requirement).","Firm, short compliance deadline (Compliance) creating immediate operational effect but no phased implementation rules.","Reference to an external technical document and a foreign AD (Requirement; Note) introduces dependency on availability and clarity of those documents.","Includes an explicit rule for spares (For spares) which broadens operational compliance beyond aircraft in service to parts suppliers and maintainers."],"plain_english_summary":"What this directive does (mechanical change)\n\n- Requires installation of a spring spacer in the hydraulic system of certain Eurocopter Dauphin helicopters, implemented in accordance with Aerospatiale Service Bulletin No. 29-01 (Requirement).\n\nWho it affects\n\n- Operators and owners of all Model SA360C and SA365 (C, C1, C2 and C3) helicopters (Applicability).\n- Maintenance organisations and technicians who perform the modification, and suppliers of spare hydraulic components (For spares).\n\nWhy it matters (stated purpose and practical effects)\n\n- The stated purpose is to prevent an overpressure in the hydraulic systems if the flange of the regulator valve stem should come off (Background). Mechanically, fitting the spring spacer is intended to limit the chance of hydraulic overpressure under that failure mode.\n\nCosts, incentives, trade-offs and compliance mechanics\n\n- Timing and operational effect: The work must be completed before the next flight after 31 December 1986 (Compliance). That creates an immediate compliance deadline: an aircraft that has not had the spacer fitted cannot be flown past that date until the action is done (Compliance).\n- Spare parts rule: Any spare parts covered by the rule must be modified or fitted before they are installed in an aircraft after 31 December 1986 (For spares). That places an obligation on parts suppliers and maintenance shops to ensure spares are compliant prior to installation.\n- Who pays and who decides: The aircraft operator or owner (or the party responsible for maintenance) bears the direct cost of parts and labour to perform the modification; the directive prescribes the required action (Requirement, For spares).\n- Dependence on external technical document: The mandatory technical steps are defined by Aerospatiale Service Bulletin No. 29-01 (Requirement). The AD also refers to a French airworthiness directive (French AD 86-176-27(B)) (Note). Operators must follow the Service Bulletin to comply, so availability and clarity of that Bulletin determine implementation detail and timing.\n\nImplementation risk and compliance burden\n\n- Implementation depends on access to the specified service bulletin and needed parts; if parts or approved procedures are not immediately available, operators face scheduling and grounding risk (Requirement; For spares).\n- The AD sets a firm compliance date rather than allowing staged or discretionary compliance (Compliance), reducing administrative discretion but increasing short-term burden on operators.\n\nEffects on private choice, markets and competition\n\n- The instrument mandates a specific retrofit for a limited set of helicopter models (Applicability). It imposes compliance costs on operators and creates demand for parts and maintenance labour; independent maintenance providers can perform the work subject to the Service Bulletin. The text does not create or describe any exclusive supplier or subsidy.\n\nSummary statement\n\n- In short: owners/operators of the listed Dauphin helicopters must have a spring spacer fitted to the hydraulic system in line with Aerospatiale Service Bulletin No. 29-01 before the aircraft is next flown after 31 December 1986, and any spares must be made compliant before installation (Applicability; Requirement; Compliance; For spares; Background)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, time-bound safety directive issued in 1987 (indicated by '1/87' in the reference). It addresses a specific mechanical defect in a specific aircraft type. There is no evidence of scope creep; it remains tightly focused on its original purpose of mandating a hydraulic system modification."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 1 defined term implicitly referenced (the Service Bulletin)","No cross-references to other legislation or regulations beyond a single note referencing a French AD","Simple conditional logic: single applicability test (specific helicopter models) and single compliance deadline","No nested exceptions or conditional sub-clauses","Straightforward command structure: 'Action in accordance with...'","Single technical requirement with clear external reference to manufacturer documentation"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order — issued by Australia's Civil Aviation Safety Authority (CASA) for certain Eurocopter Dauphin helicopters.\n\n**What it does:**\n- Requires owners and operators of specific Dauphin helicopter models (SA360C, SA365C, C1, C2, and C3) to carry out a safety modification to the hydraulic system.\n- The fix involves installing a \"spring spacer\" — a small mechanical part that prevents dangerous overpressure in the hydraulic system if a valve component (the flange of the regulator valve stem) fails or comes loose.\n\n**Who it affects:**\n- Anyone who owns, operates, or maintains the specified Dauphin helicopter models.\n- Also applies to spare parts — you cannot install affected hydraulic components in these helicopters after the deadline unless the modification has been done.\n\n**Why it matters:**\n- Hydraulic system failures in helicopters can lead to catastrophic loss of control. This AD addresses a known design flaw where a valve stem flange could detach, causing dangerous pressure buildup. The spring spacer acts as a failsafe to prevent this.\n\n**When it had to be done:**\n- Before any further flight after 31 December 1986 (for aircraft in service).\n- Before installation in an aircraft after 31 December 1986 (for spare parts).\n\n**Key reference:**\n- Operators must follow the specific instructions in **Aerospatiale Service Bulletin No. 29-01** (the manufacturer's official repair notice)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dauphin-17-hydraulic-system","history":"/api/acts/ad-dauphin-17-hydraulic-system/history","analysis":"/api/acts/ad-dauphin-17-hydraulic-system/analysis","conflicts":"/api/acts/ad-dauphin-17-hydraulic-system/conflicts","importantCases":"/api/acts/ad-dauphin-17-hydraulic-system/important-cases","documents":"/api/acts/ad-dauphin-17-hydraulic-system/documents"}}