{"id":"F2006B09385","name":"AD/ECUREUIL/81 - Main Gearbox Cowling Seals","slug":"ad-ecureuil-81-main-gearbox-cowling-seals","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":53700,"registerId":"commonwealth-F2006B09385-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 AS 350 (Ecureuil) Series Helicopters","sortOrder":0},{"sectionNumber":"AD/ECUREUIL/81 Main Gearbox Cowling Seal","sectionType":"part","heading":"AD/ECUREUIL/81 Main Gearbox Cowling Seals 1/2003","content":"# AD/ECUREUIL/81 Main Gearbox Cowling Seals 1/2003\n\nApplicability: Model AS 350 helicopters versions B, B1, B2, B3, BA, BB, and D, delivered before July 1 2002.\n\nRequirement: Replace the neoprene seals on the main gearbox cowlings with glass/silicone seals in accordance with Eurocopter Alert Service Bulletin 53.00.31.\n\nNote: DGAC AD 2002-537-094(A) refers.\n\nCompliance: Unless previously accomplished, prior to 31 May 2003.\n\nThis Airworthiness Directive becomes effective on 23 January 2003.\n\nBackground: The neoprene seals currently installed on the main gearbox cowling do not meet certification criteria regarding fire resistance.\n\n![Signature of James Coyne, Delegate of the Civil Aviation Safety Authority.](image.002.png)  \n\nJames Coyne\n\nDelegate of the Civil Aviation Safety Authority 27 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":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The AD is limited to specified AS350 model variants delivered before 1 July 2002 and mandates one corrective action (seal replacement) by a stated date, matching the safety justification that neoprene seals lack required fire resistance (Background). No expansion or narrowing of that scope beyond the text provided is evident."},"complexity_factors":["Narrow applicability — specific AS350 variants and delivery-date cutoff (Applicability).","Single, clearly stated technical action — replace neoprene seals with glass/silicone per a named Alert Service Bulletin (Requirement).","Firm compliance deadline and effective date (Compliance; Effective date).","Dependence on manufacturer service bulletin for technical instructions (Requirement).","Regulatory authority exercised under a single subregulation; limited administrative discretion (opening paragraph).","Cross-reference to a foreign AD (DGAC) but no additional procedural layers."],"plain_english_summary":"Requires owners/operators of Eurocopter AS350 (B, B1, B2, B3, BA, BB and D) helicopters delivered before 1 July 2002 to replace neoprene main-gearbox-cowling seals with glass/silicone seals, following Eurocopter Alert Service Bulletin 53.00.31, by 31 May 2003 (Applicability; Requirement; Compliance). CASA issued the AD under its regulatory power because neoprene seals do not meet fire‑resistance certification (Background).\n\nCosts fall to aircraft owners (parts and labour); compliance requires following the manufacturer service bulletin and scheduling maintenance before the deadline, with implementation risk limited mainly to parts availability and maintenance capacity."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope: addressing a specific fire-resistance deficiency in a specific component (main gearbox cowling seals) on specific helicopter models. There is no evidence of scope creep or expansion beyond this targeted safety correction."},"complexity_factors":["Very short document (under 300 words)","Only 3 operative sections: Applicability, Requirement, and Compliance","Single, unambiguous action required (seal replacement)","No defined terms section or interpretation provisions","No nested exceptions or conditional logic — straightforward deadline-based compliance","Single cross-reference to a French aviation authority directive (DGAC AD 2002-537-094(A)) and manufacturer service bulletin, but these are informational only"],"plain_english_summary":"Mandatory CASA safety order requiring owners/operators of Eurocopter AS350 (Ecureuil) B/B1/B2/B3/BA/BB/D helicopters delivered before 1 July 2002 to replace neoprene main gearbox cowling seals with fire‑resistant glass/silicone seals per Eurocopter guidance. The neoprene seals don’t meet fire-safety standards and could let flames or toxic fumes spread; the upgrade is required to keep the aircraft airworthy and legally operable, to be completed by 31 May 2003."},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-ecureuil-81-main-gearbox-cowling-seals","history":"/api/acts/ad-ecureuil-81-main-gearbox-cowling-seals/history","analysis":"/api/acts/ad-ecureuil-81-main-gearbox-cowling-seals/analysis","conflicts":"/api/acts/ad-ecureuil-81-main-gearbox-cowling-seals/conflicts","importantCases":"/api/acts/ad-ecureuil-81-main-gearbox-cowling-seals/important-cases","documents":"/api/acts/ad-ecureuil-81-main-gearbox-cowling-seals/documents"}}