{"id":"F2009L02327","name":"AD/PT6A/21 - Replacement of Compressor Delivery Heated Air Tube - CANCELLED","slug":"ad-pt6a-21-replacement-of-compressor-delivery-heated-air-tube-cancelled","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":79085,"registerId":"commonwealth-F2009L02327-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Pratt and Whitney Canada Turbine Engines","sectionType":"division","heading":"Pratt and Whitney Canada Turbine Engines - PT6A Series","content":"### Pratt and Whitney Canada Turbine Engines - PT6A Series\n\n| AD/PT6A/21 | Replacement of CompressorDelivery Heated Air Tube | 7/2009 |\n| ---------- | ------------------------------------------------- | ------ |\n\n| Requirement: | CANCELLED.                                                                                                                                                                                                                                                     |\n| ------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n|              | This AD is cancelled on 2 July 2009.                                                                                                                                                                                                                           |\n| Background:  | This unique Australian AD specified action in accordance with PWC SB No. 1315 before issue of the initial certificate of airworthiness for the aircraft, or before the engine is installed in an aircraft, after September 1979. The AD is no longer required. |\n\n![](image.001.png)\n\nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n18 May 2009","sortOrder":0},{"sectionNumber":"AD/PT6A/21","sectionType":"part","heading":"AD/PT6A/21","content":"## AD/PT6A/21","sortOrder":1},{"sectionNumber":"Replacement of CompressorDelivery Heated","sectionType":"part","heading":"Replacement of CompressorDelivery Heated Air Tube","content":"## Replacement of Compressor  \nDelivery Heated Air Tube","sortOrder":2},{"sectionNumber":"7/2009","sectionType":"part","heading":"7/2009","content":"## 7/2009","sortOrder":3}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1200},"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This instrument performs exactly one limited function: cancelling the previous Airworthiness Directive AD/PT6A/21. There is no expansion of scope, no addition of new requirements, and no alteration of the original purpose beyond the straightforward administrative cancellation."},"complexity_factors":["Single administrative action (cancellation only)","No operative provisions, obligations, or penalties","Extremely short (under 150 words of substantive content)","No defined terms or interpretation sections","No cross-references to other legislation beyond the cancelled AD and service bulletin"],"plain_english_summary":"This document **cancels a previous aviation safety rule** that applied to specific aircraft engines.\n\n**What it cancelled:**\nA previous requirement (Airworthiness Directive AD/PT6A/21) that forced owners of Pratt & Whitney Canada PT6A series turbine engines to replace or inspect a specific part—the \"compressor delivery heated air tube\"—before the engine was first certified for use or installed in an aircraft after September 1979.\n\n**What it does now:**\nAs of 2 July 2009, this maintenance requirement is **no longer necessary** and has been formally scrapped by the Civil Aviation Safety Authority (CASA).\n\n**Why it matters:**\nAircraft operators and maintenance engineers no longer need to perform this specific action to comply with Australian law, simplifying maintenance requirements for these engines."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pt6a-21-replacement-of-compressor-delivery-heated-air-tube-cancelled","history":"/api/acts/ad-pt6a-21-replacement-of-compressor-delivery-heated-air-tube-cancelled/history","analysis":"/api/acts/ad-pt6a-21-replacement-of-compressor-delivery-heated-air-tube-cancelled/analysis","conflicts":"/api/acts/ad-pt6a-21-replacement-of-compressor-delivery-heated-air-tube-cancelled/conflicts","importantCases":"/api/acts/ad-pt6a-21-replacement-of-compressor-delivery-heated-air-tube-cancelled/important-cases","documents":"/api/acts/ad-pt6a-21-replacement-of-compressor-delivery-heated-air-tube-cancelled/documents"}}