{"id":"F2006B02450","name":"AD/ARRIEL/3 Amdt 2 - Free Turbine Containment Shield","slug":"ad-arriel-3-amdt-2-free-turbine-containment-shield","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41706,"registerId":"commonwealth-F2006B02450-current","compilationNumber":null,"startDate":"2026-04-01","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/ARRIEL/3 Amdt 2 - Free Turbine Containment Shield","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nTurbomeca Turbine Engines \\- Arriel Series\n\nAD/ARRIEL/3\n\nAmdt 2\n\n  \nFree Turbine Containment Shield 7/95\n\nApplicability: Arriel 1A, 1A1, 1B, 1D, 1D1 engines.\n\nRequirement: Install a free turbine containment shield in accordance with the following requirements:\n\n    Arriel 1A and 1A1 engines incorporating modification TU 13 but not incorporating modifications TU 99 and TU 215, action in accordance with Turbomeca Service Bulletins 292-72-0206 (TU 254) and 292-72-0208 (TU 259).\n\n    2. Arriel 1B and 1D engines not incorporating modifications TU 99 and TU 215, action in accordance with Turbomeca Service Bulletins 292-72-0206 (TU 254) and 292-72-0208 (TU 259).\n\n    3. Arriel 1A and 1A1 engines incorporating modifications TU 13 and TU 99, action in accordance with Turbomeca Service Bulletins 292-72-0207 (TU 255) and 292- 72-0208 (TU 259).\n\n    4. Arriel 1B, 1D and 1D1 engines incorporating modification TU 99, action in accordance with Turbomeca Service Bulletins 292-72-0207 (TU 255) and 292-72- 0208 (TU 259).\n\nNote: DGAC Airworthiness Directive 95-069(B) refers.\n\nCompliance: Effective 22 June 1995; at next disassembly of the free turbine module assembly.\n\nBackground: This Directive has been issued to require the installation of a containment shield to the free turbine module. The requirement is to prevent the release of turbine components in the event of an overspeed failure of the free turbine. This amendment reflects the requirements of DGAC Airworthiness Directive 95-069(B).","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"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original safety purpose — preventing turbine debris release. The amendment simply updates the directive to reflect revised French aviation safety requirements (DGAC AD 95-069(B)) and clarifies applicability across different engine modification states. No scope creep detected."},"complexity_factors":["Multiple conditional applicability paths based on engine modification history (TU 13, TU 99, TU 215)","Cross-references to four external Turbomeca Service Bulletins (292-72-0206, 292-72-0207, 292-72-0208)","Reference to French regulatory instrument (DGAC Airworthiness Directive 95-069(B))","Technical aviation terminology requiring specialised knowledge (free turbine, containment shield, module assembly)","Nested logic: four distinct compliance pathways depending on engine model and modification status"],"plain_english_summary":"This safety order requires owners and maintenance organisations in Australia to fit a containment shield around the free turbine on Turbomeca Arriel 1A, 1A1, 1B, 1D and 1D1 engines—by 22 June 1995 or at the next free-turbine disassembly—using procedures that depend on existing TU modifications. It protects aircraft and occupants from debris if the turbine fails and aligns Australian rules with the French DGAC directive."},"flash_summary":{"complexity_score":5,"scope_assessment":{"changed":true,"description":"This amendment (Amdt 2) refines the original requirement by specifying which Turbomeca service bulletins apply depending on prior TU modifications to each Arriel engine model and explicitly aligns the AD with DGAC Airworthiness Directive 95‑069(B); it therefore narrows the practical compliance path from a generic shield requirement to SB‑driven, modification‑dependent actions."},"complexity_factors":["Conditional applicability by engine model and combinations of TU modification status (Requirement items 1–4) increases decision complexity for operators.","Directive delegates technical work to multiple manufacturer service bulletins (292‑72‑0206, 292‑72‑0207, 292‑72‑0208) that must be obtained and followed.","Compliance timing is linked to maintenance event ('next disassembly of the free turbine module assembly'), requiring tracking of service intervals and inventory planning.","Cross‑reference to an external DGAC Airworthiness Directive (95‑069(B)) requires checking overseas certification material for consistency.","Implementation requires specialised parts and workshop capability to install a containment shield, creating procurement and labour costs for operators."],"plain_english_summary":"This airworthiness directive requires operators of specified Turbomeca Arriel 1A/1A1/1B/1D/1D1 helicopter engines to install a free‑turbine containment shield. The installation must follow the Turbomeca service bulletins identified in the directive and is due at the next disassembly of the free‑turbine module. Operators pay for parts and maintenance and must choose the correct service bulletin based on which TU modifications are already fitted. The amendment aligns the requirement with DGAC Airworthiness Directive 95‑069(B)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-arriel-3-amdt-2-free-turbine-containment-shield","history":"/api/acts/ad-arriel-3-amdt-2-free-turbine-containment-shield/history","analysis":"/api/acts/ad-arriel-3-amdt-2-free-turbine-containment-shield/analysis","conflicts":"/api/acts/ad-arriel-3-amdt-2-free-turbine-containment-shield/conflicts","importantCases":"/api/acts/ad-arriel-3-amdt-2-free-turbine-containment-shield/important-cases","documents":"/api/acts/ad-arriel-3-amdt-2-free-turbine-containment-shield/documents"}}