{"id":"F2006B05758","name":"AD/PA-31/54 - Turbine Tailpipe Coupling - Replacement","slug":"ad-pa-31-54-turbine-tailpipe-coupling-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":135613,"registerId":"commonwealth-F2006B05758-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-31/54 - Turbine Tailpipe Coupling - 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 - 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n \n\n![](image.001.png)  Piper PA-31 Series Aeroplanes\n\n \n\nAD/PA-31/54 Turbine Tailpipe Coupling - Replacement 3/77\n\nApplicability: Model PA-31P with S/Nos 31P-1 to 31P-7730003. Document:  Piper SB No. 534.\n\nCompliance: Within 100 hours time in service after 31 March 1977.\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\n \n\n \n\n \n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The text presents a single, clearly delimited requirement (replace turbine tailpipe coupling) for a defined set of aircraft with a defined compliance window. There is no indication in this text that the scope was expanded or narrowed from an earlier version; the Applicability and Compliance sections set the operative scope and timing."},"complexity_factors":["Narrow technical scope: applies only to Model PA-31P with specified serial numbers (Applicability).","Single clear action required: replacement of a specified component (title and Compliance).","Fixed compliance timeframe: 100 hours time in service after a specific date (Compliance).","Explicit technical reference to a single service bulletin for procedures and parts (Document: Piper SB No. 534).","No additional procedural or enforcement details included in the text supplied (absence of enforcement/penalty provisions increases straightforwardness but leaves implementation details to regulators/operators)."],"plain_english_summary":"This AD mandates replacing the turbine tailpipe coupling on specified Piper PA-31P aeroplanes (listed by serial number) using Piper SB No. 534, to be done within 100 hours TIS after 31 March 1977. It affects owners/operators and maintenance organisations; compliance is required for continued airworthiness and the cost, scheduling and execution fall to the aircraft owners/operators."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive from 1977 addressing a specific mechanical defect in a limited aircraft population. It has not expanded beyond its original narrow safety purpose."},"complexity_factors":["Extremely short document (approximately 150 words)","Only 4 operative provisions: applicability, reference document, compliance deadline, and action required","No defined terms section","No cross-references to other legislation beyond the enabling regulation (CAR 1998, Part 39)","Single, unambiguous compliance condition (time-based deadline)","No exceptions, exemptions, or conditional logic"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of specific Piper PA-31P aircraft to **replace the turbine tailpipe coupling** (a component in the exhaust system of the turboprop engine). This is a safety-critical fix to prevent potential failure of the exhaust system.\n\n**Who it affects:** \n- **Aircraft:** Piper PA-31P model aeroplanes with serial numbers from 31P-1 up to 31P-7730003\n- **People:** Owners, operators, and maintenance organisations responsible for these aircraft\n\n**What must be done:**\n- The replacement must be carried out **within 100 hours of flight time** after 31 March 1977\n- The work must follow **Piper Service Bulletin No. 534** (the manufacturer's official repair instructions)\n\n**Why it matters:** Airworthiness Directives are legally binding safety mandates. Failure to comply means the aircraft cannot be considered airworthy and cannot legally fly. This particular AD addresses a specific defect in the exhaust coupling that could lead to dangerous in-flight failures."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-31-54-turbine-tailpipe-coupling-replacement","history":"/api/acts/ad-pa-31-54-turbine-tailpipe-coupling-replacement/history","analysis":"/api/acts/ad-pa-31-54-turbine-tailpipe-coupling-replacement/analysis","conflicts":"/api/acts/ad-pa-31-54-turbine-tailpipe-coupling-replacement/conflicts","importantCases":"/api/acts/ad-pa-31-54-turbine-tailpipe-coupling-replacement/important-cases","documents":"/api/acts/ad-pa-31-54-turbine-tailpipe-coupling-replacement/documents"}}