{"id":"F2005L01043","name":"AD/DAUPHIN/4 Amdt 5 - Fin to Tailboom Attachments","slug":"ad-dauphin-4-amdt-5-fin-to-tailboom-attachments","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":34595,"registerId":"commonwealth-F2005L01043-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Eurocopter SA 360 and SA 365 (Dauphin) S","sectionType":"division","heading":"Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters","content":"### Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters\n\n| AD/DAUPHIN/4 Amdt 5 | Fin to Tailboom Attachments | 6/2005 |\n| ------------------- | --------------------------- | ------ |\n\n| Applicability: | Models SA 360C, 361, 365C, C1, and C2 helicopters; pre. Mod. 07-2457 or SB 53.09 installation. |\n| -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |\n| Requirement: | 1. Unless coated with a clear lacquer, strip the paint from the external surface of the ‘fairing’ plate joining the upper tailboom to the lower fin leading edge; and perform a detailed visual inspection of the ‘fairing’ plate for cracks at the rivet lines and bend radius.Note: DGAC AD 80-238-9(B) and Aerospatiale Dauphin Service Bulletin No. 05.04 refer.2. Perform a detailed external and internal visual inspection for cracks in the fin to tailboom attachment structure. Pay particular attention to the crown attachment finger doubler, the tailboom end rib, the ends of the tailboom stringers and the inclined fenestron rib P/N 360A23.1061.01.3. Perform an X-ray inspection of the fin to tailboom attachment structure in accordance with NDT Procedure RAD/DAUPHIN/4 or other scheme approved by the Authority, to check for cracks in the crown attachment finger doubler. |\n| Compliance: | 1. Inspect in accordance with Requirement 1:a. for models modified to AMS 365A.07.2457 with a 1.6mm chemically milled fairing’ - at intervals not to exceed 100 hours time in service; or,b. for models not modified to AMS 365A.07.2457 - at intervals not to exceed 25 hours time in service.2. Inspect in accordance with Requirement 2 at each 100 hourly `S’ inspection.3. Inspect in accordance with Requirement 3 at whichever 3.a. or 3.b. time occurs later; and at the 3.c. time:a. before the tailboom to fin attachment finger doubler exceeds 500 hours total time in service; or, |\n\n| | b. before exceeding 500 hours time in service after the installation of a CAR 35 designed and approved repair to the subject crown tailboom to fin attachment finger doubler.c. thereafter at each 100 hourly `S’ inspection.Note: Any CAR 35 repair scheme must include a re-verification of the effectiveness of each of the above inspections in the presence of the repair. |\n| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| | This Amendment becomes effective on 9 June 2005. |\n| Background: | There has been a history of fatigue cracking at the tailboom to fin attachment area in the reinforcement fairing plate, the crown attachment finger doubler, the tailboom end flange, the tailboom stringers and the inclined fenestron rib P/N/ 360A23.1061.01. Reports of multiple site cracking in the crown attachment finger doubler of two Australian SA 365C-1’s extending, in one case, over a total length of 395mm, indicate that aircraft modified to AMS 365A.07.2457 are still subject to fatigue. Post modification aircraft are cracking underneath the 1.6mm chemically milled reinforcement fairing plate and are not amenable to visual inspection, due to the location of the internal frame.Amendment 1 introduced an X-ray inspection for modified aircraft with the inspection interval aligned to the 25 hour visual inspection interval for unmodified aircraft.Amendment 2 extended the X-ray inspection interval to 100 hours and introduced an inspection threshold of 500 hours for repaired aircraft, as a result of laboratory investigation. There is now also a detailed visual inspection. Further variations to the threshold and interval will be considered if a fracture mechanics based analysis is received.Amendment 3 introduced some operational flexibility by aligning the X-ray and visual inspections with the 100 hour `S’ inspection. The visual inspection is now a separate requirement and applies to all models.Amendment 4 enhanced the visual inspection of Service Bulletin No. 05.04 by requiring the external paint to be removed. This followed the discovery of a 45mm crack in a ‘fairing’ plate - inspection of this part was hindered by a thick flexible paint coating. To alleviate the burden of repetitive paint stripping, an option of coating with a suitable clear lacquer was introduced.Amendment 5 is issued to clarify applicability by specifying affected helicopters; with no change to technical content. |\n\n| | The original issue of this Airworthiness Directive became effective on 28 February 1981. |\n| --- | ---------------------------------------------------------------------------------------- |\n\n![](image.001.png) \nDavid Villiers \nDelegate of the Civil Aviation Safety Authority\n\n19 April 2005","sortOrder":0},{"sectionNumber":"AD/DAUPHIN/4 Amdt 5","sectionType":"part","heading":"AD/DAUPHIN/4 Amdt 5","content":"## AD/DAUPHIN/4 Amdt 5","sortOrder":1},{"sectionNumber":"Fin to Tailboom Attachments","sectionType":"part","heading":"Fin to Tailboom Attachments","content":"## Fin to Tailboom Attachments","sortOrder":2},{"sectionNumber":"6/2005","sectionType":"part","heading":"6/2005","content":"## 6/2005","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":7,"scope_assessment":{"changed":true,"description":"Amendment 5 clarifies applicability by specifying affected SA 360/361/365 models and pre‑modification installation status; it does not change the technical inspection or compliance requirements. The amendment alters who must comply (clarified model set) but leaves the substantive inspection regime intact."},"complexity_factors":["Multiple inspection types required: external visual, internal visual and X‑ray NDT (Requirements 1–3).","Different inspection intervals depending on aircraft modification (AMS 365A.07.2457) and repair status (Compliance table: 25h vs 100h; 500h threshold).","Mandated paint stripping of fairing plate unless a clear lacquer is applied, adding labour and consumable choices (Requirement 1).","Repairs designed under CAR 35 change inspection thresholds and require in‑situ re‑verification of inspection effectiveness (Compliance 3.b–c).","NDT must follow a specified procedure (RAD/DAUPHIN/4) or an Authority‑approved alternative, giving the regulator discretion over accepted methods (Requirement 3).","Applicability is limited to specific models and pre‑modification installations, requiring operators to determine applicability for their fleet.","Alignment with 100‑hour ‘S’ inspections for scheduling but retention of alternate 25‑hour cadence for unmodified aircraft increases planning complexity.","Hidden cracking under chemically milled fairings reduces effectiveness of visual checks and raises reliance on X‑ray results (Background)."],"plain_english_summary":"This AD requires operators of specified Eurocopter Dauphin models to remove paint (or apply a clear lacquer) and carry out detailed external and internal visual inspections plus X‑ray NDT of the fin‑to‑tailboom attachment at specified intervals tied to modification and repair status. The stated aim is to detect fatigue cracking. Owners/operators bear inspection, NDT, paint and repair costs; the regulator may approve alternate NDT procedures and CAR 35 repairs subject to re‑verification."},"kimi_summary":{"content_quality":"ok","complexity_score":6,"scope_assessment":{"changed":true,"description":"Originally issued in 1981 as a basic safety directive, this AD has expanded significantly through five amendments. It began with simple visual inspections but now encompasses: X-ray requirements (Amendment 1), extended intervals with laboratory justification (Amendment 2), operational alignment with scheduled maintenance (Amendment 3), paint stripping mandates with lacquer alternatives (Amendment 4), and refined applicability specifications (Amendment 5). The technical requirements have grown from a single inspection type to a multi-layered regime of visual, radiographic, and surface preparation requirements with varying intervals based on modification status and repair history."},"complexity_factors":["Multiple inspection types with different intervals (visual, X-ray, paint stripping) that must be tracked separately","Different compliance schedules based on modification status (modified vs unmodified aircraft)","Cross-references to external documents (DGAC AD 80-238-9(B), Aerospatiale Service Bulletin No. 05.04, NDT Procedure RAD/DAUPHIN/4, CAR 35 repair schemes)","Conditional logic for X-ray timing (whichever of two thresholds occurs later)","Specific part numbers and technical terminology (crown attachment finger doubler, fenestron rib P/N 360A23.1061.01, AMS 365A.07.2457)","Five amendments of cumulative history embedded in the background section, showing evolving regulatory response to emerging safety data","Requirement for re-verification of inspection effectiveness when repairs are made"],"plain_english_summary":"**What this is:** This is an Airworthiness Directive (AD) — a mandatory safety order issued by Australia's aviation regulator (CASA). It requires owners and operators of specific Eurocopter Dauphin helicopters to inspect and maintain a critical structural joint where the tail fin connects to the tailboom.\n\n**Who it affects:** Owners and operators of Eurocopter SA 360C, 361, 365C, C1, and C2 helicopters that haven't been modified with a specific factory upgrade (Mod. 07-2457 or Service Bulletin 53.09).\n\n**What it requires:**\n- **Paint stripping and visual inspection:** Remove paint from a 'fairing' plate (a protective cover plate) at the fin-tailboom joint and check for cracks around rivets and bends — unless the plate has been coated with clear lacquer (a transparent protective coating).\n- **Detailed structural inspection:** Look for cracks in the attachment structure, especially at a reinforced plate called the 'crown attachment finger doubler' and nearby ribs and stringers.\n- **X-ray inspection:** Use radiographic testing to detect hidden cracks in the crown attachment finger doubler.\n\n**How often:**\n- Paint stripping/visual inspection: Every 25 hours of flight time for unmodified helicopters; every 100 hours for modified ones.\n- Detailed visual inspection: Every 100 hours.\n- X-ray inspection: Must be done before 500 hours of service on the part, then every 100 hours after.\n\n**Why it matters:** This area has a history of metal fatigue and cracking. Cracks in this joint could lead to structural failure of the tail section, potentially causing loss of control or crash. Previous versions of this directive revealed cracks up to 395mm long in Australian aircraft. The inspections are designed to catch cracks before they become dangerous."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-dauphin-4-amdt-5-fin-to-tailboom-attachments","history":"/api/acts/ad-dauphin-4-amdt-5-fin-to-tailboom-attachments/history","analysis":"/api/acts/ad-dauphin-4-amdt-5-fin-to-tailboom-attachments/analysis","conflicts":"/api/acts/ad-dauphin-4-amdt-5-fin-to-tailboom-attachments/conflicts","importantCases":"/api/acts/ad-dauphin-4-amdt-5-fin-to-tailboom-attachments/important-cases","documents":"/api/acts/ad-dauphin-4-amdt-5-fin-to-tailboom-attachments/documents"}}