{"id":"F2006B06378","name":"AD/PT6T/9 - Reduced 2nd and 3rd Stage Compressor Disc Lives","slug":"ad-pt6t-9-reduced-2nd-and-3rd-stage-compressor-disc-lives","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":47652,"registerId":"commonwealth-F2006B06378-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PT6T/9 - Reduced 2nd and 3rd Stage Compressor Disc Lives","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 - PT6T Series\n\n \n\nAD/PT6T/9 Reduced 2nd and 3rd Stage Compressor Disc Lives\n\n\n5/92\n\n \n\nApplicability: All PT6T series engines and spare compressor discs as listed by serial number in Pratt and Whitney Canada Service Bulletin No. 5266.\n\n \n\nRequirement: Action in accordance with Pratt and Whitney Canada Service Bulletin No. 5266. Compliance:               Effective 30 April 1992. As detailed in requirement document.\n\nBackground:  This Directive requires removal from service, and X-ray inspection of, certain second and third stage compressor discs. This requirement follows advice from the manufacturer that certain discs may have been contaminated with tungsten inclusions during the disc production process.\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 targeted safety directive addressing a specific manufacturing defect in specific engine parts. The scope remains precisely limited to the identified contamination issue and affected serial numbers."},"complexity_factors":["Very short document (under 200 words)","Only 1 defined applicability criterion (serial numbers listed in external Service Bulletin)","Single requirement with clear compliance deadline","No nested exceptions or conditional logic","Cross-reference to only 1 external document (Service Bulletin No. 5266)","No internal definitions section"],"plain_english_summary":"This AD mandates removal and X‑ray inspection of certain Pratt & Whitney Canada PT6T 2nd‑ and 3rd‑stage compressor discs (including listed spares) to detect tungsten inclusions that can cause cracking and catastrophic engine failure. It affects operators, maintenance organizations, and parts owners; compliance follows P&WC Service Bulletin No. 5266. The action was required by 30 April 1992 to protect flight safety and avoid regulatory penalties."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive's scope is limited to PT6T series engines and spare compressor discs listed by serial number in Service Bulletin No. 5266. The text provides no indication the scope was broadened or narrowed beyond this stated applicability; the measures align with the stated purpose to remove and inspect potentially contaminated discs."},"complexity_factors":["Cross-reference to Pratt & Whitney Canada Service Bulletin No. 5266 for the technical actions and affected serial numbers (Requirement: \"Action in accordance with Pratt and Whitney Canada Service Bulletin No. 5266\").","Serial‑number‑specific applicability requires tracking engines and spare discs against the SB list (Applicability: \"as listed by serial number in Pratt and Whitney Canada Service Bulletin No. 5266\").","Mandatory removal from service and X‑ray inspection creates operational disruption, inspection capability needs and potential replacement costs (Background: \"removal from service, and X-ray inspection of, certain second and third stage compressor discs\").","Fixed compliance start date imposes scheduling constraints (Compliance: \"Effective 30 April 1992\").","Statutory basis within Part 39 Airworthiness Directives requires formal regulatory compliance and recordkeeping (header: \"Civil Aviation Regulations 1998, PART 39\").","Root cause is manufacturer‑reported manufacturing contamination (tungsten inclusions), which raises supplier quality‑control and liability considerations (Background: \"may have been contaminated with tungsten inclusions during the disc production process\")."],"plain_english_summary":"This airworthiness directive requires owners and operators of Pratt & Whitney Canada PT6T engines (and listed spare compressor discs) to remove certain 2nd and 3rd stage compressor discs and have them X‑ray inspected, following Pratt & Whitney Canada Service Bulletin No. 5266. The action responds to manufacturer advice that some discs may contain tungsten inclusions; compliance creates inspection, downtime and parts‑management costs for operators."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pt6t-9-reduced-2nd-and-3rd-stage-compressor-disc-lives","history":"/api/acts/ad-pt6t-9-reduced-2nd-and-3rd-stage-compressor-disc-lives/history","analysis":"/api/acts/ad-pt6t-9-reduced-2nd-and-3rd-stage-compressor-disc-lives/analysis","conflicts":"/api/acts/ad-pt6t-9-reduced-2nd-and-3rd-stage-compressor-disc-lives/conflicts","importantCases":"/api/acts/ad-pt6t-9-reduced-2nd-and-3rd-stage-compressor-disc-lives/important-cases","documents":"/api/acts/ad-pt6t-9-reduced-2nd-and-3rd-stage-compressor-disc-lives/documents"}}