{"id":"F2006B09232","name":"AD/DHC-8/74 - Oxygen - Deletion of Selector Stop on Flow Control Valve","slug":"ad-dhc-8-74-oxygen-deletion-of-selector-stop-on-flow-control-valve","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53118,"registerId":"commonwealth-F2006B09232-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-8/74 - Oxygen - Deletion of Selector Stop on Flow Control Valve","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)  \n![](image.002.png)  \nBombardier (Boeing Canada/De Havilland) DHC-8 Series Aeroplanes\n\nAIRWORTHINESS 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.\n\nAD/DHC-8/74 Oxygen \\- Deletion of Selector Stop\n\non Flow Control Valve\n\n  \n11/2000\n\nApplicability: DHC-8 aircraft Models 102, 103, 106, 201, 202, 301, 311, 314, and 315, serial numbers 003 to 468 inclusive and 472 with all-passenger oxygen configurations CR 835CH00009, CR 835CH00011, CR 835CH02001, CSI 82279 or CSI 82093\n\ninstalled.\n\nRequirement: Incorporate Bombardier Modification 8/2989 (Deletion of Selector Stop on Flow Control Valve) in accordance with Bombardier Service Bulletin 8-35-19 dated 17 August 2000.\n\nNote: Transport Canada AD CF-2000-26 refers.\n\nCompliance: Unless previously accomplished, within 90 days time in service after the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 2 November 2000.\n\nBackground: This Directive addresses aircraft fitted with an Automatic Passenger Presentation of Oxygen System (APPOS). Field reports have indicated that the selector stop on the flow valve control panel can be installed incorrectly, preventing the selection of either “ON” or “AUTO”. In such a case, oxygen would be prevented from being available to passengers in case of an emergency.\n\n![](image.003.png)  \n\nEugene Paul Holzapfel\n\nDelegate of the Civil Aviation Safety Authority 25 September 2000\n\n![](image.002.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 4 October 2000.","sortOrder":0}],"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's scope aligns with its stated purpose: it targets the specific flow-control valve selector stop on defined DHC-8 models/serial numbers with particular oxygen configurations and mandates a defined manufacturer modification within a set compliance period. No broader changes to applicability or additional obligations beyond the single modification requirement are introduced in the text provided."},"complexity_factors":["Narrow technical scope: targets a specific component (selector stop on flow-control valve) and requires a single manufacturer modification (Bombardier Mod 8/2989) — Requirement section.","Precise applicability: limited to listed DHC-8 models, serial numbers and particular all-passenger oxygen configurations — Applicability section.","Reliance on external document: compliance mandated by following Bombardier Service Bulletin 8-35-19 (operator must obtain and implement that SB) — Requirement section.","Time pressure: fixed compliance window of 90 days time in service after the effective date creates scheduling and maintenance-planning constraints — Compliance section.","Safety-critical consequence: failure mode (selector stop installed incorrectly) can prevent ON/AUTO selection and block passenger oxygen in emergencies — Background section.","Regulatory enforcement: issued under CAR 1998 subregulation 39.1(1), creating a mandatory airworthiness obligation for operators — introductory paragraph.","Operational impact: modification likely requires maintenance resources, potential aircraft downtime and parts/labour paid by the operator (implied by who must accomplish the AD)."],"plain_english_summary":"Requires removal of the selector stop on the passenger oxygen flow-control valve by incorporating Bombardier Modification 8/2989, in accordance with Bombardier Service Bulletin 8-35-19. It applies to DHC-8 Models 102–315, serial numbers 003–468 and 472 with specified all-passenger oxygen configurations. The Directive responds to reports that an incorrectly installed selector stop can prevent selection of ON or AUTO, which would stop passenger oxygen supply in an emergency; operators must complete the modification within 90 days time in service after the effective date."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow Airworthiness Directive addressing a specific unsafe condition in specific aircraft. It has not expanded beyond its original purpose of mandating a safety modification to the oxygen system."},"complexity_factors":["Single, specific technical requirement with clear reference to manufacturer documentation","Limited applicability — only 9 specific aircraft models with 5 specific oxygen system configurations","No nested exceptions or conditional logic; straightforward 90-day compliance deadline","Only one defined term implied (APPOS — Automatic Passenger Presentation of Oxygen System) in background","No cross-references to other legislation beyond a note about a Canadian equivalent directive","Total length: approximately 300 words"],"plain_english_summary":"This mandatory Airworthiness Directive orders airlines operating certain Bombardier DHC‑8 (Dash 8) aircraft with specified serial numbers and passenger oxygen system part numbers to remove a mechanical selector stop on the flow control valve (Bombardier Mod 8/2989 per Service Bulletin 8‑35‑19). The change prevents incorrect installation that can block crew from selecting passenger oxygen ON/AUTO in depressurisation events. Compliance is required within 90 days of the directive (effective 2 Nov 2000)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-8-74-oxygen-deletion-of-selector-stop-on-flow-control-valve","history":"/api/acts/ad-dhc-8-74-oxygen-deletion-of-selector-stop-on-flow-control-valve/history","analysis":"/api/acts/ad-dhc-8-74-oxygen-deletion-of-selector-stop-on-flow-control-valve/analysis","conflicts":"/api/acts/ad-dhc-8-74-oxygen-deletion-of-selector-stop-on-flow-control-valve/conflicts","importantCases":"/api/acts/ad-dhc-8-74-oxygen-deletion-of-selector-stop-on-flow-control-valve/important-cases","documents":"/api/acts/ad-dhc-8-74-oxygen-deletion-of-selector-stop-on-flow-control-valve/documents"}}