{"id":"F2006B04336","name":"AD/BELL 204/33 - Main Transmission Spiral Bevel Gear","slug":"ad-bell-204-33-main-transmission-spiral-bevel-gear","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44151,"registerId":"commonwealth-F2006B04336-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 204/33 Main Transmission Spiral ","sectionType":"part","heading":"AD/BELL 204/33 Main Transmission Spiral Bevel Gear 8/2000","content":"# AD/BELL 204/33 Main Transmission Spiral Bevel Gear 8/2000\n\nApplicability: All model 204B with main transmission spiral bevel gear P/N 204-040-701-103 with;\n\n    less than 250 hours time in service at the effective date of this directive, and\n    delivered as spares or in a new or overhauled transmission between 01 January 1988 and 04 April 1989, and\n\n    with the serial numbers specified in the Requirement document.\n\n    Requirement: Action in accordance with the technical requirements of FAA AD 89-08-05.\n\nCompliance: As specified in the Requirement document.\n\nThis Airworthiness Directive becomes effective on 10 August 2000.\n\nBackground: This directive is issued to prevent failure in service of particular spiral bevel gears which in turn could cause the loss of a helicopter. It 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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive is narrowly targeted to specified spiral bevel gears (part number, hours, delivery dates, and listed serial numbers) and invokes FAA AD 89‑08‑05 for technical action. The text reinstates the AD series but does not expand the population or obligations beyond preventing failure of those listed gears (Applicability; Requirement; Background)."},"complexity_factors":["Cross‑reference to an external technical instrument (FAA AD 89‑08‑05) requires consultees to obtain and follow another regulator's document (Requirement).","Narrow, multi‑condition applicability (part number, hours in service, delivery window, and specific serial numbers) increases administrative burden to identify affected items (Applicability).","Compliance timing is delegated to the referenced Requirement document rather than stated in full here, creating reliance on external compliance details (Compliance).","Traceability and record‑checking for serial numbers and time‑in‑service impose operator/maintenance workload and potential cost (Applicability; Compliance).","Regulatory decision comes from a CASA delegate and reinstates the AD series after a lapse, indicating administrative discretion in issuance (Background)."],"plain_english_summary":"This Airworthiness Directive requires owners/operators to perform the FAA‑specified inspection/repair actions for particular main transmission spiral‑bevel gears used in Bell 204B helicopters (and those delivered as spares) to prevent in‑service gear failure. It applies to gears with limited hours and listed serial numbers; the Civil Aviation Safety Authority (CASA) issued the directive and affected owners/operators must comply and bear the inspection/repair costs (Applicability; Requirement; Compliance; Background)."},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This is a narrow, targeted safety directive addressing a specific mechanical defect in a specific helicopter model. It has not expanded beyond its original purpose of preventing gear failure."},"complexity_factors":["Short document (under 500 words)","Only 3 defined applicability criteria (hours, date range, serial numbers)","Single cross-reference to external technical document (FAA AD 89-08-05) — actual work instructions are 'incorporated by reference' rather than spelled out","No nested exceptions or conditional logic within the document itself","Straightforward temporal compliance structure"],"plain_english_summary":"Australia’s Civil Aviation Safety Authority has ordered inspection or replacement of a specific spiral bevel gear in Bell 204B main transmissions (certain part numbers/serials delivered 1988–89 with under 250 flight hours). Operators and owners must follow the FAA’s technical instructions (AD 89‑08‑05) by its deadlines. The action addresses a gear failure that can cause catastrophic in‑flight loss and marks the reinstatement of Australia’s Airworthiness Directive system."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-204-33-main-transmission-spiral-bevel-gear","history":"/api/acts/ad-bell-204-33-main-transmission-spiral-bevel-gear/history","analysis":"/api/acts/ad-bell-204-33-main-transmission-spiral-bevel-gear/analysis","conflicts":"/api/acts/ad-bell-204-33-main-transmission-spiral-bevel-gear/conflicts","importantCases":"/api/acts/ad-bell-204-33-main-transmission-spiral-bevel-gear/important-cases","documents":"/api/acts/ad-bell-204-33-main-transmission-spiral-bevel-gear/documents"}}