{"id":"F2006B04347","name":"AD/BELL 204/43 - Tailboom Vertical Fin Spar","slug":"ad-bell-204-43-tailboom-vertical-fin-spar","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44161,"registerId":"commonwealth-F2006B04347-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.002.png)\n\n![](image.002.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.","sortOrder":0},{"sectionNumber":"AD/BELL 204/43 Tailboom Vertical Fin Spa","sectionType":"part","heading":"AD/BELL 204/43 Tailboom Vertical Fin Spar 8/2000","content":"# AD/BELL 204/43 Tailboom Vertical Fin Spar 8/2000\n\nApplicability: Model 204B.\n\nRequirement: Action in accordance with FAA AD 97-18-11.\n\nCompliance: Modify and inspect before further flight after the effective date of this directive, thereafter inspect at intervals not exceeding 8 hours time in service.\n\nThis Airworthiness Directive becomes effective on 10 August 2000.\n\nBackground: The directive was raised following the inflight failure of fin spars in both civil and military helicopters of the same design. This directive also follows the re-introduction of the AD Series after sixteen years.\n\n![](image.003.png)  \n\nDavid Alan Villiers\n\nDelegate of the Civil Aviation Safety Authority 6 July 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 12 July 2000.","sortOrder":1}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific structural failure in a specific helicopter model. The reference to the AD Series reintroduction is contextual background, not an expansion of regulatory scope."},"complexity_factors":["Very short document (under 300 words)","Only 1 defined applicability (Model 204B)","Single requirement referencing external document (FAA AD 97-18-11)","Simple compliance structure: one-time modification + recurring inspection","No nested exceptions or conditional logic","No internal cross-references to other legislation","Clear, linear structure: Applicability → Requirement → Compliance → Background"],"plain_english_summary":"This mandatory AD requires Australian owners/operators of Bell 204B helicopters to modify and inspect the tailboom vertical fin spar — a component that has failed in flight — following FAA AD 97-18-11. The work must be done before next flight after 10 Aug 2000, then re-inspected every 8 flight hours.\n\nIt’s issued by CASA (adopting the FAA AD) and affects anyone who owns, operates, or maintains Bell 204Bs in Australia."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"Based solely on this text, the directive reaffirms requirements for Model 204B helicopters by mandating compliance with FAA AD 97-18-11. The instrument does not state any expansion or narrowing of applicability compared with prior ADs; it simply re‑introduced the AD series and applied the FAA AD requirements to Model 204B."},"complexity_factors":["External cross-reference: the Requirement directs compliance with FAA AD 97-18-11, so operators must obtain and follow an external technical document rather than relying solely on this instrument.","Immediate and frequent compliance: mandate to modify and inspect before further flight and then at intervals not exceeding 8 hours (Compliance clause) increases operational disruption and scheduling complexity.","Technical engineering work: the subject is a primary structural component (tailboom vertical fin spar), requiring qualified maintenance, possible parts, and engineering approvals.","Narrow applicability but concentrated impact: applies only to Model 204B (Applicability), concentrating compliance costs on a specific operator group.","Delegated enforcement basis: issued under subregulation 39.1(1) of CAR 1998 by a CASA delegate, indicating administrative discretion in issuing the AD (preamble).","Safety-driven origin: Background cites in‑flight failures in civil and military helicopters, implying urgent corrective action and potential for operational restrictions.","Administrative history: re‑introduction of the AD Series after sixteen years may require operators to reconcile previous guidance with current requirements."],"plain_english_summary":"Requires operators of Bell Model 204B helicopters to modify the tailboom vertical fin spar and carry out inspections in accordance with FAA AD 97-18-11. Compliance must be completed before the next flight after the directive’s effective date, with repeat inspections at intervals not exceeding eight hours time in service.\n\nIssued after reported in‑flight fin‑spar failures, the directive imposes maintenance work, inspection time and potential downtime on owners/operators while leaving the technical instructions to the referenced FAA AD."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-204-43-tailboom-vertical-fin-spar","history":"/api/acts/ad-bell-204-43-tailboom-vertical-fin-spar/history","analysis":"/api/acts/ad-bell-204-43-tailboom-vertical-fin-spar/analysis","conflicts":"/api/acts/ad-bell-204-43-tailboom-vertical-fin-spar/conflicts","importantCases":"/api/acts/ad-bell-204-43-tailboom-vertical-fin-spar/important-cases","documents":"/api/acts/ad-bell-204-43-tailboom-vertical-fin-spar/documents"}}