{"id":"F2007L02131","name":"AD/BELL 222/38 - Power Turbine RPM Steady-State Operation","slug":"ad-bell-222-38-power-turbine-rpm-steady-state-operation","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":67289,"registerId":"commonwealth-F2007L02131-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Bell Helicopter Textron Canada (BHTC) 22","sectionType":"division","heading":"Bell Helicopter Textron Canada (BHTC) 222 Series Helicopters","content":"### Bell Helicopter Textron Canada (BHTC) 222 Series Helicopters\n\n| AD/BELL 222/38 | Power Turbine RPM Steady-State Operation | 8/2007 |\n| -------------- | ---------------------------------------- | ------ |\n\n| Applicability: | Bell Helicopter Textron Canada (BHTC) Model 230 helicopters, serial numbers 23001 through 23038.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Insert flight manual BHT-230-FM-1 Revision 5, or later approved revisions, into the rotorcraft flight manual and advise the pilot of this change.2. Install the decal as per Alert Service Bulletin 230-05-33, dated 10 June 2005, or later NAA approved revisions.Note: Transport Canada AD CF-2005-24 dated 4 July 2005 refers.                                                                                                                                                                                                                                                                           |\n| Compliance:    | 1. Within 30 calendar days after the effective date of this directive, unless previously accomplished.2. In conjunction with Requirement 1 of this AD.                                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n|                | This Airworthiness Directive becomes effective on 2 August 2007.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |\n| Background:    | Transport Canada has advised of multiple reports of failure of the third stage turbine wheel used in both the Rolls-Royce 250-C3OS and 250-C47B engines. There have been six in-flight failures of which three have occurred on the engine utilized by BHTC for the Model 230 helicopter. Rolls-Royce has determined that detrimental vibrations can occur within a particular range of turbine speed as a potential contributing factor to these failures. BHTC revised their rotorcraft flight manual and provided a decal to inform pilots to avoid steady-state operations at these engine turbine speeds. |\n\n![](image.001.png)  \nDavid Punshon  \nDelegate of the Civil Aviation Safety Authority\n\n21 June 2007","sortOrder":0},{"sectionNumber":"AD/BELL 222/38","sectionType":"part","heading":"AD/BELL 222/38","content":"## AD/BELL 222/38","sortOrder":1},{"sectionNumber":"Power Turbine RPM Steady-State Operation","sectionType":"part","heading":"Power Turbine RPM Steady-State Operation","content":"## Power Turbine RPM Steady-State Operation","sortOrder":2},{"sectionNumber":"8/2007","sectionType":"part","heading":"8/2007","content":"## 8/2007","sortOrder":3}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive implements targeted operational restrictions and information updates to mitigate third‑stage turbine wheel failures, consistent with the stated safety purpose (Background and Requirement). It does not broaden applicability beyond the listed Model 230 serial numbers or add novel regulatory powers; it prescribes specific, short-term compliance actions and references existing service bulletin and Transport Canada AD guidance."},"complexity_factors":["Narrow applicability to a small, identified fleet (Applicability: Model 230, SN 23001–23038) — lowers administrative complexity but concentrates compliance.","Simple, discrete compliance tasks (Requirement: insert flight manual revision; install decal) — reduces procedural complexity.","Short mandatory timeframe (Compliance: 30 calendar days) — increases logistical pressure on operators.","Technical root cause and operational effect are specific (Background: Rolls‑Royce found detrimental vibrations at particular turbine speeds) — requires pilot behaviour change rather than engineering modification.","Reliance on external documents (Requirement references Alert Service Bulletin 230-05-33 and NAA-approved revisions) — creates dependency on manufacturer/authority approvals.","Low regulatory discretion and clear directive form — enforcement and interpretation are straightforward."],"plain_english_summary":"Requires inserting Revision 5 (or later) of the BHT-230 flight manual and installing a cockpit decal (per Alert Service Bulletin 230-05-33) to warn pilots to avoid steady-state power‑turbine speeds that can produce harmful vibrations. Applies to Bell Model 230 helicopters, serial numbers 23001–23038, with actions due within 30 days.\n\nThe directive follows Transport Canada and Rolls‑Royce findings linking third‑stage turbine wheel failures to a specific turbine‑speed band; it changes pilot operating behaviour and imposes minor administrative and installation costs."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, targeted Airworthiness Directive addressing a specific safety defect in a specific aircraft model. The scope remains precisely limited to the identified turbine failure risk in Bell 230 helicopters and has not expanded beyond this original safety purpose."},"complexity_factors":["Very short document (approximately 250 words)","Only 2 substantive requirements with clear sequential numbering","Single applicability criterion (specific model and serial number range)","Minimal cross-referencing (only references to flight manual revision, service bulletin, and related Canadian AD)","Simple compliance timeline (30 days, concurrent implementation)","No defined terms section or interpretation provisions","No conditional logic, exceptions, or nested provisions"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of Bell Helicopter Model 230 (S/N 23001–23038) to update the flight manual (Revision 5 or later) and install a cockpit warning decal within 30 days. \n\nIt's an emergency safety measure after in‑flight turbine failures linked to certain steady engine speeds that cause damaging vibrations and can lead to catastrophic engine loss."},"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-bell-222-38-power-turbine-rpm-steady-state-operation","history":"/api/acts/ad-bell-222-38-power-turbine-rpm-steady-state-operation/history","analysis":"/api/acts/ad-bell-222-38-power-turbine-rpm-steady-state-operation/analysis","conflicts":"/api/acts/ad-bell-222-38-power-turbine-rpm-steady-state-operation/conflicts","importantCases":"/api/acts/ad-bell-222-38-power-turbine-rpm-steady-state-operation/important-cases","documents":"/api/acts/ad-bell-222-38-power-turbine-rpm-steady-state-operation/documents"}}