{"id":"F2009L03202","name":"AD/ARRIEL/32 Amdt 2 - Engine - Module M04 Power Turbine Blades","slug":"ad-arriel-32-amdt-2-engine-module-m04-power-turbine-blades","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":140525,"registerId":"commonwealth-F2009L03202-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Turbomeca Turbine Engines - Arriel Serie","sectionType":"division","heading":"Turbomeca Turbine Engines - Arriel Series","content":"### Turbomeca Turbine Engines - Arriel Series\n\n| AD/ARRIEL/32 Amdt 2 | Engine - Module M04 Power Turbine Blades | 10/2009 TX |\n| ------------------- | ---------------------------------------- | ---------- |\n\n| Applicability: | Turboméca S.A. Arriel 1B, 1D and 1D1 turboshaft engines, fitted with Modules M04 (Power Turbine) as identified in figure 1 of Turboméca Mandatory Service Bulletin (MSB) A292 72 0827 version C, and Arriel 2B, 2B1 and 2B1A turboshaft engines, fitted with Modules M04 as identified in figure 1 of Turboméca MSB A292 72 2833 version C.Note 1: Arriel 1B, 1D and 1D1 turboshaft engines are known to be installed on, but not limited to, Eurocopter AS 350 B, AS 350 BA, AS 350 BB, AS 350 B1 and AS 350 B2 helicopters; Arriel 2B, 2B1 and 2B1A turboshaft engines are known to be installed on, but not limited to, Eurocopter AS 350 B3, EC 130 B4 and Changhe Z11 helicopters.Note 2: The variants above are installed on single-engine helicopters. |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement: | 1. For engines with a Module M04 (PT module) which has accumulated 5,000 Total Power Turbine (PT) Cycles or more at the effective date of this AD:Replace the module M04, or PT wheel assembly, or PT blades, as instructed in paragraph 2.B.(1)(b) of Turboméca MSB A292 72 0827 version C for Arriel 1 engines and A292 72 2833 version C for Arriel 2 engines.2. For engines with a Module M04 which has accumulated less than 5,000 Total PT Cycles at the effective date of this AD:a. Update the module M04 log card and the engine log book to enter the 5,000 PT Cycle life-limit of the PT blades as instructed in paragraph 2.B.(1)(a) of Turboméca MSB A292 72 0827 version C for Arriel 1 engines andA292 72 2833 version C for Arriel 2 engines.b. Replace the module M04, or PT wheel assembly, or PT blades as instructed in paragraph 2.B.(1)(b) of Turboméca MSB A292 72 0827 version C for Arriel 1 engines and A292 72 2833 version C for Arriel 2 engines.The use of later approved revisions of these documents is acceptable for compliance with the requirements of this AD. |\n\n| | Note 3: Serial numbers of PT wheel assemblies and Modules M04 (PT) as listed in Figure 1 of the referenced MSB are the confirmed location of the affected PT blades. The engine serial numbers are also provided for information when available. In case of conflicts between serial numbers Turboméca should be contacted for resolution.Note 4: EASA AD 2009-0112R1 dated 30 July 2009 refers. This AD supersedes EASA AD 2009-0112. |\n| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Compliance: | For Requirement 1 - Before further flight after the effective date of the AD, unless previously accomplished.For Requirement 2a - Before accomplishment of Requirement 2b. of this AD.For Requirement 2b - Before accumulation of 5,000 Total PT Cycles on a given Module M04. |\n| | This Amendment becomes effective on 14 August 2009. |\n| Background: | During production of Arriel 1 and Arriel 2 Power Turbine (PT) wheels, geometric non-conformities on blade fir-tree roots have been detected by Turboméca. Potentially non-conforming PT blades have been traced as having been installed on Module M04 (PT) listed in Mandatory Service Bulletin (MSB) A292 72 0827 for Arriel 1 engines and A292 72 2833 for Arriel 2 engines.The geometric non-conformities of the blades may potentially lead to a reduction in the fatigue resistance of PT blades to a lower level than their authorized in service use limit. This reduction of fatigue resistance can potentially result in blade release, which could cause an uncommanded in-flight shut down. On a single-engine helicopter, the result may be an emergency autorotation landing.For the reasons stated above, the original issue of this AD required a restriction of the cyclic use limit of these PT blades to 1,000 flight cycles. For PT blades having reached a number of flight cycles superior or equal to 1,000, removal of Module M04, or PT wheel assembly, or PT blades was required prior to next flight.Amendment 1 revised the reference documents to version B. Version B includes additional modules that are affected. Additional testing has also been conducted which allowed increasing the cyclic limit to 2,000 cycles.Amendment 2 revises the reference documents to version C. Version C includes information regarding additional testing that has been conducted which allows increasing the cyclic limit to 5,000 cycles. |\n\n| | The original issue of this AD became effective on 27 March 2009.Amendment 1 of this AD became effective on 1 June 2009. |\n| --- | ----------------------------------------------------------------------------------------------------------------------- |\n\n![](image.001.png) \nJames Coyne \nDelegate of the Civil Aviation Safety Authority\n\n12 August 2009","sortOrder":0},{"sectionNumber":"AD/ARRIEL/32 Amdt 2","sectionType":"part","heading":"AD/ARRIEL/32 Amdt 2","content":"## AD/ARRIEL/32 Amdt 2","sortOrder":1},{"sectionNumber":"Engine - Module M04 Power Turbine Blades","sectionType":"part","heading":"Engine - Module M04 Power Turbine Blades","content":"## Engine - Module M04 Power Turbine Blades","sortOrder":2},{"sectionNumber":"10/2009 TX","sectionType":"part","heading":"10/2009 TX","content":"## 10/2009 TX","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This legislation maintains its original scope. It is an amendment to an existing Airworthiness Directive that progressively adjusts the technical compliance parameters (flight cycle limits) based on new testing data, without expanding beyond the original purpose of addressing the specific manufacturing defect in Arriel engine power turbine blades."},"complexity_factors":["Multiple engine variants with slightly different compliance paths (Arriel 1 vs Arriel 2 series)","Two-tier compliance structure based on accumulated flight cycles (5,000+ vs under 5,000)","Three-part sequential requirement for lower-use engines (logbook update before replacement, with separate deadlines)","Cross-references to external manufacturer documents (Turboméca MSBs) that are incorporated by reference and version-controlled (version C specifically)","Nested applicability criteria requiring cross-checking serial numbers against manufacturer figures","Amendment history creates layered context (original AD, Amendment 1, Amendment 2) with evolving cycle limits","Technical aviation terminology requiring specialized knowledge (PT cycles, fir-tree roots, modules, MSBs)"],"plain_english_summary":"This AD orders owners/operators of Turboméca Arriel turboshaft engines (used in single‑engine helicopters such as the AS350 series, EC130 B4 and Changhe Z11) to inspect and replace power turbine blades with defective fir‑tree roots to prevent fatigue and in‑flight blade loss. Compliance depends on engine cycles: high‑use units must be rectified immediately; others must be limited to a 5,000‑cycle life and have parts replaced before that limit. It prevents catastrophic engine failure and forced autorotation on single‑engine helicopters."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":true,"description":"The AD's scope has been amended since issue: initial cyclic limit restrictions were progressively increased (originally 1,000 cycles, then 2,000, now 5,000) and the referenced Turboméca MSBs were updated to include additional affected modules. The amendment both relaxes the short term cycle restriction compared with the original AD and expands the set of modules identified in the MSBs; it also supersedes the earlier EASA AD referenced in the document."},"complexity_factors":["Different actions depending on module accumulated PT cycles at the AD effective date (≥5,000 vs <5,000).","Multiple compliance timings (before further flight; before accumulation to 5,000 PT cycles; administrative logbook update).","Applicability across several engine variants and helicopters increases tracking burden for operators.","Compliance requires use of specific Turboméca Mandatory Service Bulletin versions (later approved revisions acceptable).","Serial‑number mapping in the MSB identifies affected PT wheel assemblies/modules; conflicts require contacting Turboméca for resolution.","Amendment history changed the numeric life limit (1,000 → 2,000 → 5,000), so affected operators must reconcile prior actions with the current limit."],"plain_english_summary":"This airworthiness directive requires operators of Turboméca Arriel 1B/1D/1D1 and 2B-series turboshaft engines fitted with Module M04 power turbines to record a 5,000 Total Power Turbine (PT) cycle life limit for the PT blades and to replace the M04 module, PT wheel assembly or PT blades according to the cited Turboméca Mandatory Service Bulletins. Engines already at or above 5,000 PT cycles must have the parts replaced before the next flight. The rule addresses detected geometric non‑conformities that can reduce blade fatigue life and risk blade release."},"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"}},"importantCases":[],"_links":{"self":"/api/acts/ad-arriel-32-amdt-2-engine-module-m04-power-turbine-blades","history":"/api/acts/ad-arriel-32-amdt-2-engine-module-m04-power-turbine-blades/history","analysis":"/api/acts/ad-arriel-32-amdt-2-engine-module-m04-power-turbine-blades/analysis","conflicts":"/api/acts/ad-arriel-32-amdt-2-engine-module-m04-power-turbine-blades/conflicts","importantCases":"/api/acts/ad-arriel-32-amdt-2-engine-module-m04-power-turbine-blades/important-cases","documents":"/api/acts/ad-arriel-32-amdt-2-engine-module-m04-power-turbine-blades/documents"}}