{"id":"F2006B08765","name":"AD/DAUPHIN/53 - Fuselage 9 Degree Frame Stretcher Support","slug":"ad-dauphin-53-fuselage-9-degree-frame-stretcher-support","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52045,"registerId":"commonwealth-F2006B08765-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# AIRWORTHINESS DIRECTIVE\n\n![](image.001.png)\n\n![](image.001.png)  \nFor the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.\n\nEurocopter SA 360 & SA 365 (Dauphin) Series Helicopters","sortOrder":0},{"sectionNumber":"AD/DAUPHIN/53 Fuselage 9 Degree Frame St","sectionType":"part","heading":"AD/DAUPHIN/53 Fuselage 9 Degree Frame Stretcher Support 7/2001","content":"# AD/DAUPHIN/53 Fuselage 9 Degree Frame Stretcher Support 7/2001\n\nDM\n\nApplicability: AS 365 helicopters, versions N, N1, N2, and N3.\n\nRequirement: Action in accordance with Eurocopter AS 365 N Alert Service Bulletin No. 53.00.43.\n\nNote: DGAC AD 2001-061-053(A) refers.\n\nCompliance: For the initial check, unless already accomplished:\n\n    Within 50 flight hours after 30 May 2001 for aircraft that have accumulated more than 5250 total flight hours;\n\n    b. Before the accumulation of 5300 total flight hours for aircraft that have accumulated less than 5250 total flight hours.\n\nThereafter accomplish repetitive inspections as specified in the Requirement document until a flange reinforcement plate is installed in accordance with paragraph\n\n2.B.2 of the Requirement document , or a customised repair defined by Eurocopter is accomplished.\n\nThis Airworthiness Directive becomes effective on 30 May 2001.\n\nBackground: The DGAC received a report of a web of insufficient thickness at one of the attachment holes of the stretcher support on the 9 degree fuselage frame. This deficiency was discovered during a check by the manufacturer, and if not corrected, could lead to crack propagation.\n\n![Signature of David Alan Villiers Delegate of the Civil Aviation Safety Authority](image.002.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 23 May 2001\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 30 May 2001.","sortOrder":1}],"analysis":{"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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific structural defect in specific helicopter models. It has not expanded beyond its original safety purpose."},"complexity_factors":["Short, single-purpose directive with one specific mechanical issue","Only 4 defined applicability criteria (helicopter models N, N1, N2, N3)","Simple conditional compliance structure based on flight hours (two thresholds: 5250 and 5300 hours)","Single cross-reference to French authority (DGAC) and Eurocopter service bulletin","No nested exceptions or complex definitional sections","Clear termination condition (installation of reinforcement plate or customised repair)"],"plain_english_summary":"This AD requires operators of Eurocopter Dauphin AS365 N/N1/N2/N3 helicopters to inspect and, if needed, reinforce the 9° frame stretcher support because a too‑thin support web at a bolt hole can crack and risk structural failure. \n\nAircraft with >5,250 hours must inspect within 50 flight hours after 30 May 2001; those under 5,250 must inspect before 5,300 hours. Follow Eurocopter ASB No. 53.00.43 and repeat inspections until a reinforcement or approved repair is fitted."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD remains narrowly focused on a single structural deficiency (insufficient web thickness at a stretcher-support attachment hole on the 9° fuselage frame) for a defined set of AS 365 variants. It requires inspections and either a reinforcement plate installation or an approved customised repair. There is no evidence in the text that the AD expanded beyond that original, stated safety purpose."},"complexity_factors":["Single-aircraft type applicability (4 AS 365 N-series variants) — narrow scope","Reference to a single external technical document: Eurocopter AS 365 N Alert Service Bulletin No. 53.00.43","Two-tier initial compliance timing tied to total aircraft flight hours (>5250 vs <5250)","Repetitive inspections required until a specified permanent modification (flange reinforcement plate per paragraph 2.B.2 of the Requirement document) or an approved customised repair is completed","Cross-reference to DGAC AD 2001-061-053(A) (foreign authority AD)","Short document length but dependency on the service bulletin for procedural detail","Minor textual ambiguity/formatting issue in the AD text around the paragraph reference increases practical clarity burden"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- Requires owners/operators of Eurocopter AS 365 (Dauphin) helicopters — versions N, N1, N2 and N3 — to carry out inspections and, where necessary, repairs or a reinforcement modification to the stretcher-support area of the 9° fuselage frame.\n- The inspections and any corrective work must be done in accordance with Eurocopter Alert Service Bulletin AS 365 N No. 53.00.43 (the “Requirement document”) and in the timing set out in this AD.\n- Initial inspection timing is tied to total airframe hours: either within 50 flight hours after 30 May 2001 for aircraft already above 5,250 total hours, or before they reach 5,300 total hours if they have less than 5,250 hours.\n- After the initial check, operators must carry out the repetitive inspections specified in the Requirement document until either a flange reinforcement plate is installed (as specified in paragraph 2.B.2 of the Requirement document) or a Eurocopter-defined customised repair is completed.\n- The AD became effective on 30 May 2001.\n\n**Who this affects**\n\n- Direct: owners, operators and maintenance organisations responsible for AS 365 N-series helicopters.\n- Indirect: lessors and insurers who need to ensure compliance, and third-party maintenance providers that perform the inspections and modifications.\n\n**Why it matters (stated purpose and how the rule addresses it)**\n\n- The stated safety concern: the manufacturer found a section of insufficient thickness at an attachment hole of the stretcher support on the 9° fuselage frame; if uncorrected, this could allow crack propagation.\n- The AD uses a prescriptive, manufacturer-sourced remedy: (a) inspect for the defect on a flight-hours schedule tied to total airframe hours, (b) repeat inspections at the intervals in the service bulletin, and (c) fit a reinforcement plate or an approved customised repair to terminate the inspection cycle.\n\n**Who pays and who decides**\n\n- The cost of inspections, parts (reinforcement plate if fitted), labour and aircraft downtime falls on the operator/owner. If the operator uses a maintenance organisation, that business will bill for labour and parts.\n- Civil Aviation Safety Authority (CASA), through its delegate, imposes the mandatory requirement; Eurocopter (manufacturer) supplies the technical instructions and defines acceptable customised repairs.\n\n**Practical effects on behaviour and operations**\n\n- Operators must track total airframe hours and schedule the required initial check within the specified thresholds.\n- Operators will perform recurring inspections until the reinforcement plate or an approved repair is fitted; this creates recurring maintenance tasks and possible aircraft downtime until the permanent fix is done.\n- Maintenance providers will implement the inspection and either fit the reinforcement plate per paragraph 2.B.2 of the service bulletin or carry out a manufacturer-defined customised repair.\n\n**Costs, incentives, trade-offs and implementation risks**\n\n- Direct costs: inspection labour, possible non-destructive testing or access/tear-down time, spare part (reinforcement plate) and fitting labour. Aircraft may be out of service while work is done.\n- Incentive structure: operators can avoid repeated inspections by installing the reinforcement plate or completing an approved customised repair, which concentrates cost up-front in exchange for lower ongoing inspection burden.\n- Opportunity cost: aircraft hours lost to inspections/repairs could reduce revenue or require replacement capacity.\n- Implementation risk: the AD mandates compliance with an external service bulletin; operators depend on that document for detailed procedures. Any ambiguity in the service bulletin (the AD references paragraph 2.B.2 and a “customised repair” definition) or delays in obtaining parts could slow compliance.\n- Compliance burden: repetitive inspections until fixed create ongoing monitoring and maintenance scheduling requirements. Failure to comply risks regulatory enforcement and, if the defect manifests, structural damage.\n\n**Effects on competition, prices and business choice (market-liberal lens)**\n\n- Small or single-aircraft operators face proportionally higher per-aircraft costs and downtime; larger fleets can spread the one-off fix cost.\n- Independent MROs (maintenance, repair and overhaul providers) can compete to perform the inspections and modifications, provided they follow the service bulletin and hold any required approvals.\n- No change to ownership rights or contracts is imposed by the AD itself, but operators may negotiate lease or insurance arrangements to manage the cost/risk.\n\n**Cross-references and provenance**\n\n- The AD cites Eurocopter Alert Service Bulletin AS 365 N No. 53.00.43 for the technical steps and refers to DGAC AD 2001-061-053(A). The AD becomes effective 30 May 2001 and is signed by a CASA delegate.\n\n**Net summary**\n\n- This is a targeted airworthiness directive requiring time-limited inspections, and ultimately either a reinforcement plate installation or authorised customised repair, to address a specific insufficient‑thickness condition at a stretcher-support attachment on the 9° fuselage frame of AS 365 N-series helicopters. Operators bear the costs and scheduling burden; the AD reduces inspection burden only after the permanent modification or approved repair is fitted."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dauphin-53-fuselage-9-degree-frame-stretcher-support","history":"/api/acts/ad-dauphin-53-fuselage-9-degree-frame-stretcher-support/history","analysis":"/api/acts/ad-dauphin-53-fuselage-9-degree-frame-stretcher-support/analysis","conflicts":"/api/acts/ad-dauphin-53-fuselage-9-degree-frame-stretcher-support/conflicts","importantCases":"/api/acts/ad-dauphin-53-fuselage-9-degree-frame-stretcher-support/important-cases","documents":"/api/acts/ad-dauphin-53-fuselage-9-degree-frame-stretcher-support/documents"}}