{"id":"F2006B06361","name":"AD/PT6A/21 - Replacement of Compressor Delivery Heated Air Tube","slug":"ad-pt6a-21-replacement-of-compressor-delivery-heated-air-tube","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47598,"registerId":"commonwealth-F2006B06361-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PT6A/21 - Replacement of Compressor Delivery Heated Air Tube","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)  Pratt and Whitney Canada Turbine Engines - PT6A Series\n\n \n\nAD/PT6A/21 Replacement of Compressor Delivery Heated Air Tube\n\n\n10/85\n\n \n\nApplicability: PT6A-34AG.\n\n \n\nDocument: 1. Pratt & Whitney Aircraft of Canada Ltd. Engine SB No. 1315, or\n\n \n\n2. AD/UAC-T/34.\n\n \n\nCompliance: Before initial certification or Before installation in an aircraft after 1 September 1979.\n\n \n\nBackground:  Overseas there have been failures of the Compressor delivery heated air tubes. In order to preclude such failures, this directive introduces a flexible hose which replaces the rear compressor delivery heated tube.\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":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":2005},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive maintains its original narrow scope addressing the specific safety issue of compressor delivery heated air tube failures on PT6A-34AG engines."},"complexity_factors":["Limited applicability to single engine model (PT6A-34AG)","Short, single-issue mechanical directive with no conditional exceptions","References external technical documents (Service Bulletin No. 1315)","Simple binary compliance deadline structure"],"plain_english_summary":"This is a **mandatory aviation safety rule** (called an Airworthiness Directive) issued by the Civil Aviation Safety Authority under the Civil Aviation Regulations.\n\n**What it requires**\nOwners and operators must replace a specific metal air tube on Pratt & Whitney Canada PT6A-34AG turbine engines with a flexible hose version.\n\n**Who is affected**\nAnyone responsible for aircraft powered by PT6A-34AG engines (commonly used in agricultural and commuter aircraft).\n\n**Compliance deadline**\nYou must make this replacement before:\n- The aircraft's initial certification, **or**\n- Installing the engine in an aircraft after 1 September 1979\n\n**Why this matters**\nThe original rigid \"compressor delivery heated air tube\" (a pipe carrying hot compressed air) was failing in overseas operations, creating risks of engine damage or failure. The flexible hose prevents these failures.\n\n**How to comply**\nFollow the instructions in Pratt & Whitney Service Bulletin No. 1315 (or equivalent directive AD/UAC-T/34) when performing the replacement."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pt6a-21-replacement-of-compressor-delivery-heated-air-tube","history":"/api/acts/ad-pt6a-21-replacement-of-compressor-delivery-heated-air-tube/history","analysis":"/api/acts/ad-pt6a-21-replacement-of-compressor-delivery-heated-air-tube/analysis","conflicts":"/api/acts/ad-pt6a-21-replacement-of-compressor-delivery-heated-air-tube/conflicts","importantCases":"/api/acts/ad-pt6a-21-replacement-of-compressor-delivery-heated-air-tube/important-cases","documents":"/api/acts/ad-pt6a-21-replacement-of-compressor-delivery-heated-air-tube/documents"}}