{"id":"F2006B10802","name":"AD/IAI-W/26 - Oxygen Shut-off Valve","slug":"ad-iai-w-26-oxygen-shut-off-valve","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":56273,"registerId":"commonwealth-F2006B10802-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\nIsrael Aircraft Industries 1123 and 1124 (Westwind) Series Aeroplanes","sortOrder":0},{"sectionNumber":"AD/IAI-W/26 Oxygen Shut-off Valve 1/2003","sectionType":"part","heading":"AD/IAI-W/26 Oxygen Shut-off Valve 1/2003","content":"# AD/IAI-W/26 Oxygen Shut-off Valve 1/2003\n\nApplicability: Model 1123, 1124 and 1124A series aeroplanes.\n\nRequirement: Remove the existing oxygen shut-off valve and replace it with a Scott® slow opening valve having part number 27550-3 in accordance with Israel Aircraft Industries Alert Service Bulletin (ASB) 1123-35-048 or ASB 1124-35-137 both dated 23 September 2002, as applicable.\n\nNote: Israel CAA AD 35-02-10-12 refers.\n\nCompliance: Within 200 hours time in service after the effective date of this Directive.\n\nThis Airworthiness Directive becomes effective on 23 January 2003.\n\nBackground: The oxygen system of the Astra is designed so that high oxygen pressure is maintained from the cylinder to the pressure reducer-regulator located downstream of the shut-off valve. If this valve is quickly opened, overheating and subsequent fire may occur due to rapid adiabatic compression.\n\nThis Directive requires the replacement of the existing oxygen shut-off valve with a slow opening valve.\n\n![Signature of James Coyne](image.002.png)  \n\nJames Coyne\n\nDelegate of the Civil Aviation Safe ty Authority 25 November 2002\n\n![](image.001.png)  \n\nThe above AD is notified in the Commonwealth of Australia Gazette on 18 December 2002.","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 is a targeted safety directive addressing a specific mechanical defect in a narrow class of aircraft. The scope remains precisely limited to the oxygen valve replacement as originally intended."},"complexity_factors":["Single, unambiguous requirement with one specific action","Only 3 aircraft models covered in applicability section","Single compliance timeframe (200 hours time in service)","No nested exceptions, conditional logic, or alternative compliance paths","Only one defined term of note ('time in service')","No cross-references to other legislation beyond the enabling regulation (CAR 1998 subreg 39.1(1))","Straightforward causal chain in background (quick opening → compression → heat → fire)"],"plain_english_summary":"This safety order requires owners/operators of Israel Aircraft Industries Westwind 1123, 1124, and 1124A aircraft to replace a hazardous oxygen shut-off valve with a slow-opening Scott® valve (P/N 27550-3) to eliminate a fire risk from rapid oxygen adiabatic compression.  \n\nAffected operators must install the specified valve per the manufacturer’s service bulletin within 200 flight hours. The directive took effect 23 January 2003."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The Directive's scope is consistent with its stated safety purpose: it targets specified Astra models and mandates a one‑for‑one valve replacement to mitigate overheating/fire risk from rapid valve opening. It neither broadens affected aircraft beyond the listed models nor adds ongoing monitoring or reporting obligations beyond the replacement and ASB compliance (Applicability; Requirement; Compliance)."},"complexity_factors":["Narrow applicability: applies only to IAI models 1123, 1124 and 1124A (Applicability).","Single, discrete action required: remove existing valve and fit specified Scott slow‑opening valve P/N 27550‑3 (Requirement).","Clear compliance window: replacement required within 200 hours time in service (Compliance) — creates scheduling but not procedural uncertainty.","Work governed by referenced manufacturer service bulletins (IAI ASB 1123‑35‑048 / 1124‑35‑137 dated 23 Sep 2002), which centralise technical instructions but require access to those documents (Requirement).","Regulatory basis: issued by CASA delegate under CAR 1998 subregulation 39.1(1) — discretionary regulatory instrument with compulsory effect for affected operators (preamble/signature).","Operational risks lie in part availability and maintenance scheduling rather than in diagnostic complexity (Background + Requirement).","Precise part number requirement reduces interpretation ambiguity but increases dependence on supply chain for P/N 27550‑3 (Requirement)."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of Israel Aircraft Industries models 1123, 1124 and 1124A to remove the existing oxygen shut-off valve and install a Scott slow‑opening valve (P/N 27550‑3) per the applicable IAI Alert Service Bulletin, within 200 hours time in service of the effective date (23 Jan 2003). CASA issued the AD under CAR 1998 subregulation 39.1(1) to address a fire risk from rapid valve opening. Operators pay for and schedule the mechanical replacement according to the ASB instructions."}},"importantCases":[],"_links":{"self":"/api/acts/ad-iai-w-26-oxygen-shut-off-valve","history":"/api/acts/ad-iai-w-26-oxygen-shut-off-valve/history","analysis":"/api/acts/ad-iai-w-26-oxygen-shut-off-valve/analysis","conflicts":"/api/acts/ad-iai-w-26-oxygen-shut-off-valve/conflicts","importantCases":"/api/acts/ad-iai-w-26-oxygen-shut-off-valve/important-cases","documents":"/api/acts/ad-iai-w-26-oxygen-shut-off-valve/documents"}}