{"id":"F2006B08754","name":"AD/DAUPHIN/43 - Main Rotor Head Frequency Adapter","slug":"ad-dauphin-43-main-rotor-head-frequency-adapter","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52021,"registerId":"commonwealth-F2006B08754-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DAUPHIN/43 - Main Rotor Head Frequency Adapter","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nEurocopter SA 360 and SA 365 (Dauphin) Series Helicopters\n\nAD/DAUPHIN/43 Main Rotor Head Frequency Adapter 10/96\n\nApplicability: Model AS365N, N1, and N2 fitted with main rotor head frequency adapters:\n\n    P/N 704A33-640-031 (E1T2624-01A) or delivered in pairs under P/N 365A31- 1858-01, manufactured before the second quarter of 1991 (2T91) with a serial number equal to, or less than 8188; or\n\n    2. P/N 704A33-640-046 (E1T3023-01) or delivered in pairs under the P/N 365A31- 1858-02, manufactured before the second quarter of 1991 (2T91) with a serial number equal to, or less than 3122.\n\nRequirement: Action in accordance with Eurocopter AS 365 SB 01.00.44.\n\nNote: DGAC AD 96-117-040 refers.\n\nCompliance: Within 100 hours time in service after 12 September 1996, or prior to 12 March 1997 whichever occurs first.\n\nBackground: Severe vibration has been found to be caused by separation of the elastomer and the centre metal section of the frequency adapters. The separation may be caused by a fault in the production process for certain frequency adapters.","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive stays within its original technical remit: it identifies affected parts and helicopters, mandates corrective action per the manufacturer’s service bulletin, and sets a compliance deadline (Applicability; Requirement; Compliance). It continues to target the specific defect (elastomer/metal separation) described in the Background rather than expanding to other systems or models."},"complexity_factors":["Targeted technical scope: specific helicopter models and narrowly defined part numbers/serial ranges (Applicability).","Dependency on an external technical document for required actions (Eurocopter AS365 SB 01.00.44) rather than full steps stated in the directive (Requirement).","Short, mandatory compliance window with a dual trigger (100 hours TIS after 12 Sept 1996 or before 12 Mar 1997) creates scheduling pressure (Compliance).","Clear, single-mode failure cause identified (elastomer separation causing vibration) which narrows diagnostic ambiguity (Background).","Operational impact concentrated on affected operators who must fund and schedule maintenance; limited fleet breadth reduces regulatory complexity."],"plain_english_summary":"This airworthiness directive requires operators of Eurocopter AS365 N/N1/N2 helicopters fitted with specified main-rotor frequency adapters (parts made before 2Q1991 with listed serial numbers) to perform the corrective steps in Eurocopter Service Bulletin AS365 SB 01.00.44. Compliance is within 100 hours time‑in‑service after 12 Sept 1996 or before 12 Mar 1997. Operators must arrange and pay for inspections/repairs, CASA enforces the requirement, and the action addresses a defect where the elastomer can separate from the centre metal and cause severe vibration."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific manufacturing defect in specific helicopter components. It has not expanded beyond its original purpose of mandating corrective action for the identified vibration risk."},"complexity_factors":["Single, specific technical requirement referencing an external manufacturer service bulletin","Precise applicability criteria using part numbers, manufacturing dates, and serial number ranges","Simple compliance deadline structure (hours-based or calendar-based, whichever is earlier)","No nested exceptions or conditional logic — straightforward 'if your helicopter has these parts, do this action'","Limited cross-referencing (only to French aviation authority DGAC AD and Eurocopter SB)","Short document length (single page directive)"],"plain_english_summary":"This CASA Airworthiness Directive mandates owners/operators of certain Eurocopter Dauphin (AS365/SA360) helicopters to inspect or replace specific main rotor head frequency adapters (older serials/part numbers) because the elastomer can separate from the metal core, causing severe vibration and potential catastrophic rotor failure. Compliance must follow Eurocopter Service Bulletin 01.00.44 within the specified flight‑hour/time limits. Non‑compliance grounds the aircraft."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dauphin-43-main-rotor-head-frequency-adapter","history":"/api/acts/ad-dauphin-43-main-rotor-head-frequency-adapter/history","analysis":"/api/acts/ad-dauphin-43-main-rotor-head-frequency-adapter/analysis","conflicts":"/api/acts/ad-dauphin-43-main-rotor-head-frequency-adapter/conflicts","importantCases":"/api/acts/ad-dauphin-43-main-rotor-head-frequency-adapter/important-cases","documents":"/api/acts/ad-dauphin-43-main-rotor-head-frequency-adapter/documents"}}