{"id":"F2006B07434","name":"AD/TPE 331/25 - Third Stage Turbine Wheel P/N 3101516/1 - Replacement","slug":"ad-tpe-331-25-third-stage-turbine-wheel-p-n-3101516-1-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":49718,"registerId":"commonwealth-F2006B07434-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/TPE 331/25 - Third Stage Turbine Wheel P/N 3101516/1 - Replacement","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-generator: Aspose.Words for .NET 22.10.0\n---\n\n?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"no\"?>\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  AlliedSignal (Garrett/AiResearch) Turbine Engines - TPE 331 Series\n\n \n\nAD/TPE 331/25  Third Stage Turbine Wheel P/N 3101516/1 - Replacement\n\n\n3/86\n\n \n\nApplicability: TPE-331-10-501G models fitted with third stage turbine wheel P/N 3101516/1.\n\n \n\nRequirement: Remove the forged third stage turbine wheel, P/No. 3101516/1, and replace it with a cast third stage turbine wheel, P/No. 3102655/1; or\n\n \n\nAD/AIR-T/34.\n\n \n\nCompliance: Within 100 hours time in service after 11 June 1979.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a narrow, technical safety directive focused on a single engine part. It has not expanded beyond its original purpose of mandating replacement of a specific defective component."},"complexity_factors":["Very short document (approximately 150 words)","Only 2 defined elements: specific engine model (TPE-331-10-501G) and specific part numbers (P/N 3101516/1 and P/N 3102655/1)","Single, unambiguous requirement with one alternative compliance path","No cross-references to other legislation (except a single reference to another AD)","No conditional logic or nested exceptions","Clear, fixed compliance deadline"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to specific aircraft engines: the **TPE-331-10-501G** models made by AlliedSignal (formerly Garrett/AiResearch).\n\n**What it requires:**\n- **Who must act:** Owners or operators of these specific engines that contain a particular part — the \"third stage turbine wheel\" with part number 3101516/1.\n- **What must be done:** Remove that specific forged turbine wheel and replace it with a different, cast version (part number 3102655/1). Alternatively, comply with a different directive called AD/AIR-T/34.\n- **Why it matters:** Airworthiness Directives are issued when a safety defect is discovered. This suggests the original forged turbine wheel was found to have a flaw that could cause engine failure — a serious risk to aircraft safety.\n- **Deadline:** The replacement had to be completed within **100 hours of flight time** after 11 June 1979.\n\n**In short:** This is a historical safety mandate forcing the replacement of a potentially dangerous engine component in specific aircraft engines."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The text sets a narrow, specific requirement for engines fitted with P/N 3101516/1 and prescribes a replacement part and deadline. The instrument itself contains no indication that this scope was altered from an earlier or original intent; it applies only to the described engine model and part number (Applicability; Requirement; Compliance)."},"complexity_factors":["Single, narrowly defined applicability (TPE-331-10-501G engines fitted with P/N 3101516/1) (Applicability).","Single prescriptive technical action: remove forged wheel P/No. 3101516/1 and install cast wheel P/No. 3102655/1 (Requirement).","Short, specific compliance window (within 100 hours time in service after 11 June 1979) (Compliance).","Reference to one alternate compliance instrument (AD/AIR-T/34) adds minor procedural choice (Requirement).","No detailed procedural, certification or record-keeping provisions in the text increases practical clarity but shifts detail to maintenance practice and referenced AD if used."],"plain_english_summary":"AlliedSignal TPE‑331‑10‑501G engines fitted with forged third‑stage turbine wheel P/N 3101516/1 must have that wheel removed and replaced with cast P/N 3102655/1 within 100 flight hours after 11 June 1979. This mandatory AD affects engine owners/operators and maintenance suppliers; an alternate compliance route is available by following AD/AIR‑T/34."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tpe-331-25-third-stage-turbine-wheel-p-n-3101516-1-replacement","history":"/api/acts/ad-tpe-331-25-third-stage-turbine-wheel-p-n-3101516-1-replacement/history","analysis":"/api/acts/ad-tpe-331-25-third-stage-turbine-wheel-p-n-3101516-1-replacement/analysis","conflicts":"/api/acts/ad-tpe-331-25-third-stage-turbine-wheel-p-n-3101516-1-replacement/conflicts","importantCases":"/api/acts/ad-tpe-331-25-third-stage-turbine-wheel-p-n-3101516-1-replacement/important-cases","documents":"/api/acts/ad-tpe-331-25-third-stage-turbine-wheel-p-n-3101516-1-replacement/documents"}}