{"id":"F2006B07471","name":"AD/TPE 331/61 - 1st Stage Turbine Disk","slug":"ad-tpe-331-61-1st-stage-turbine-disk","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49864,"registerId":"commonwealth-F2006B07471-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AIRWORTHINESS DIRECTIVE","sectionType":"part","heading":"AIRWORTHINESS DIRECTIVE","content":"# ![](image.001.png)  \nAIRWORTHINESS DIRECTIVE\n\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 CASR 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\n![](image.001.png)\n\nAlliedSignal (Garrett/AiResearch) Turbine Engines \\- TPE 331 Series","sortOrder":0},{"sectionNumber":"AD/TPE 331/61 1st Stage Turbine Disk 9/2","sectionType":"part","heading":"AD/TPE 331/61 1st Stage Turbine Disk 9/2004","content":"# AD/TPE 331/61 1st Stage Turbine Disk 9/2004\n\nApplicability: Honeywell International Inc. (formerly AlliedSignal Inc.) TPE331 series engines as detailed in Honeywell International Inc. Alert Service Bulletin (ASB) TPE331-A72- 2102, dated 28 March 2002, fitted with 1st stage turbine disk part number (P/N) 3101520-1 or P/N 3107079-1, with serial numbers (SNs) listed in Table 1 of Honeywell International Inc. ASB TPE331-A72-2102.\n\nNote 1: These engines are installed on, but not limited to Mitsubishi MU-2B series, Construcciones Aeronauticas S.A. (CASA) C-212 series, Fairchild SA226 series (Swearingen Merlin and Metro series), Twin Commander 680 and 690 series (Jetprop Commander), Dornier 228 series, Beech 18 and 45 series, Beech Models JRB-6, 3N, 3TM, and B100, Cessna Aircraft Company Model 441 Conquest, and Jetstream 3201 series aeroplanes.\n\nRequirement: 1. Unless previously accomplished perform a initial fluorescent penetrant inspection (FPI) of first stage turbine disks, P/N 3101520-1, in accordance with 2.A. (4)(a) through 2.A. (4)(d) of Accomplishment Instructions of ASB TPE331-A72-2102.\n\n    2. Perform repetitive FPIs of first stage turbine disks P/N 3101520-1 and P/N 3107079-1, in accordance with 2.B. (3)(a) through 2.B. (3)(d) of Accomplishment Instructions of ASB TPE331-A72-2102.\n\nNote 2: First stage turbine disks, P/N 3107079-1, do not require initial inspection because they received an initial FPI and ECI at the time of conversion.\n\n    3. For first stage turbine disks that pass FPI, perform eddy current inspection (ECI).\n\nNote 3: FAA AD 2004-09-29 Amdt 39-13619 refers.\n\nNote 4: First stage turbine disks that pass FPI must be ECI before they are returned to service. Information on procedures for returning disks to Honeywell Engines, Systems, & Services, for ECI, can be found in ASB TPE331-A72-2102.\n\nCompliance: For Requirement 1:\n\nFor first stage turbine disks with 4,100 cycles-since-new (CSN) or less, inspect at next access, but no later than 4,500 CSN.","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"},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The AD targets inspections of first‑stage turbine disks identified by specific part and serial numbers per the Honeywell ASB; it does not expand applicability beyond those engines/disks or add new corrective actions in the text provided."},"complexity_factors":["Technical inspection methods required (FPI and ECI) requiring specialised maintenance skills and equipment","Applicability limited to specific part numbers and serial numbers listed in the manufacturer’s Alert Service Bulletin","Timing constraint tied to cycles‑since‑new (CSN) values and ‘‘next access’’ events, creating operational scheduling impacts","Dependence on manufacturer’s Accomplishment Instructions (ASB TPE331‑A72‑2102) for procedural detail","Potential need to return parts to manufacturer for ECI, adding logistical and cost considerations","Cross‑reference to FAA AD increases regulatory linkage and potential for differing jurisdictional interpretations"],"plain_english_summary":"This Directive requires fluorescent penetrant inspections (FPI) and follow-up eddy current inspections (ECI) of specified first‑stage turbine disks (P/N 3101520‑1 and 3107079‑1) in Honeywell TPE331 engines listed in the manufacturer’s Alert Service Bulletin. It affects aircraft operators and maintenance organisations that own or service those engines: they must schedule inspections by the stated cycle counts or next access, may need to send disks to Honeywell for ECI, and will bear the inspection, downtime and repair costs."},"kimi_summary":{"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":false,"description":"This appears to be a standard, targeted airworthiness directive addressing a specific safety defect in a defined engine population. The scope remains tightly focused on the 1st stage turbine disk issue as originally identified. No evidence of scope creep beyond the original safety purpose."},"complexity_factors":["Heavy reliance on external technical documents (Honeywell Alert Service Bulletin TPE331-A72-2102) for actual inspection procedures — the AD itself doesn't contain the detailed instructions","Multiple part numbers (P/N 3101520-1 and P/N 3107079-1) with different inspection requirements based on prior history","Cross-reference to FAA AD 2004-09-29 Amdt 39-13619 (US equivalent regulation)","Technical aviation terminology throughout (CSN — cycles-since-new, FPI, ECI, ASB)","Conditional logic: different compliance timelines based on cycle counts, with one part number exempt from initial inspection due to prior conversion work","Incomplete compliance section — cuts off mid-sentence after specifying Requirement 1 timing"],"plain_english_summary":"This AD mandates fluorescent penetrant and eddy‑current inspections of the 1st‑stage turbine disk on certain Honeywell TPE331 engines. It applies to operators of affected types (e.g., Mitsubishi MU‑2, Cessna Conquest, Fairchild Metro) used in regional, charter, and cargo services.\n\nThe rule requires initial and repetitive inspections based on cycle counts because undetected disk cracks can lead to catastrophic engine failure, so timely detection is compulsory."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tpe-331-61-1st-stage-turbine-disk","history":"/api/acts/ad-tpe-331-61-1st-stage-turbine-disk/history","analysis":"/api/acts/ad-tpe-331-61-1st-stage-turbine-disk/analysis","conflicts":"/api/acts/ad-tpe-331-61-1st-stage-turbine-disk/conflicts","importantCases":"/api/acts/ad-tpe-331-61-1st-stage-turbine-disk/important-cases","documents":"/api/acts/ad-tpe-331-61-1st-stage-turbine-disk/documents"}}