{"id":"F2009L03422","name":"AD/TPE 331/13 - Short Torsion Shaft Spline Wear - Inspection - CANCELLED","slug":"ad-tpe-331-13-short-torsion-shaft-spline-wear-inspection-cancelled","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":141004,"registerId":"commonwealth-F2009L03422-current","compilationNumber":null,"startDate":"2026-04-03","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"AlliedSignal (Garrett/AiResearch) Turbin","sectionType":"division","heading":"AlliedSignal (Garrett/AiResearch) Turbine Engines - TPE 331 Series","content":"### AlliedSignal (Garrett/AiResearch) Turbine Engines - TPE 331 Series\n\n| AD/TPE 331/13 | Short Torsion Shaft Spline Wear - Inspection | 10/2009 |\n| ------------- | -------------------------------------------- | ------- |\n\n| Requirement: | CANCELLED.                                                                                                                                                                                                        |\n| ------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n|              | This AD is cancelled on 24 September 2009.                                                                                                                                                                        |\n| Background:  | This unique Australian AD specified inspection and replacement of the short tension shaft in accordance with Airesearch SB No. 72-0024 between 1350 and 1750 hours time in service. The AD is no longer required. |\n\n![](image.001.png)\n\nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n14 August 2009","sortOrder":0},{"sectionNumber":"AD/TPE 331/13","sectionType":"part","heading":"AD/TPE 331/13","content":"## AD/TPE 331/13","sortOrder":1},{"sectionNumber":"Short Torsion Shaft Spline Wear - Inspec","sectionType":"part","heading":"Short Torsion Shaft Spline Wear - Inspection","content":"## Short Torsion Shaft Spline Wear - Inspection","sortOrder":2},{"sectionNumber":"10/2009","sectionType":"part","heading":"10/2009","content":"## 10/2009","sortOrder":3}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":2100},"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This instrument serves solely to terminate the legal effect of a previous Airworthiness Directive. It does not expand, narrow, or alter the substantive scope of the original legislation; rather, it removes the ongoing obligation entirely. The original scope (inspection of short torsion shaft splines) is simply extinguished rather than modified."},"complexity_factors":["Single operative provision (cancellation) with no substantive regulatory text","No definitions, interpretation clauses, or technical legal terminology","No cross-references to other legislation beyond the cancelled AD itself","Extremely short length (under 150 words of operative content)","No conditional logic, exceptions, or procedural steps required for compliance"],"plain_english_summary":"**What this is:** This document officially scraps a previous aviation safety rule (called an Airworthiness Directive or AD) that required owners of certain aircraft engines to perform a specific mechanical inspection.\n\n**What it did previously:** The original rule required inspection—and potential replacement—of the **short torsion shaft spline** (a component that transmits power) on AlliedSignal (Garrett/AiResearch) TPE 331 series turbine engines once they had flown between 1,350 and 1,750 hours.\n\n**What it does now:** The requirement is **completely cancelled**. Aircraft operators no longer need to carry out this inspection or keep records to prove compliance with this specific rule.\n\n**Who it affects:** Owners and operators of aircraft fitted with TPE 331 turbine engines—commonly found in regional airliners, cargo planes, and agricultural aircraft.\n\n**Why it matters:** This reduces maintenance costs and administrative burdens for operators because one specific repetitive inspection has been removed from their compliance obligations."}},"importantCases":[],"_links":{"self":"/api/acts/ad-tpe-331-13-short-torsion-shaft-spline-wear-inspection-cancelled","history":"/api/acts/ad-tpe-331-13-short-torsion-shaft-spline-wear-inspection-cancelled/history","analysis":"/api/acts/ad-tpe-331-13-short-torsion-shaft-spline-wear-inspection-cancelled/analysis","conflicts":"/api/acts/ad-tpe-331-13-short-torsion-shaft-spline-wear-inspection-cancelled/conflicts","importantCases":"/api/acts/ad-tpe-331-13-short-torsion-shaft-spline-wear-inspection-cancelled/important-cases","documents":"/api/acts/ad-tpe-331-13-short-torsion-shaft-spline-wear-inspection-cancelled/documents"}}