{"id":"F2006B05757","name":"AD/PA-31/53 - Exhaust Transition Coupling - Retirement Life","slug":"ad-pa-31-53-exhaust-transition-coupling-retirement-life","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":135610,"registerId":"commonwealth-F2006B05757-current","compilationNumber":null,"startDate":"2026-04-03","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-31/53 - Exhaust Transition Coupling - Retirement Life","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-31/53 Exhaust Transition Coupling - Retirement Life 3/77\n\nApplicability: Model PA-31P.\n\n \n\nRequirement: Retire from service the exhaust transition clamp P/N LW-12125-3 and gasket P/No.\n\n75845.\n\n \n\nCompliance: 1. For aircraft with less than 400 hours time in service:\n\n \n\nBefore attaining 600 hours time in service.\n\n \n\n2.    For aircraft with more than 400 hours time in service: Within 200 hours time in service after.\n\n3.    For Paras. 1 and 2:\n\n \n\nThereafter at intervals not exceeding 600 hours time in service.\n\n \n\nNote: For further details refer Lycoming SB No. 395.\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":1870},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This directive maintains its original narrow technical scope as a specific maintenance requirement for exhaust components on a single aircraft model, with no evidence of expansion into broader operational or regulatory areas."},"complexity_factors":["Single aircraft model applicability (Model PA-31P only)","Clear hardware mandate with specific part numbers (no ambiguity)","Simple binary condition based on flight hours (under/over 400 hours)","No defined terms section or interpretive provisions","Only one external reference (manufacturer service bulletin)"],"plain_english_summary":"This AD requires owners/operators of Piper PA-31P aircraft to permanently remove and replace specific exhaust parts (transition clamp LW-12125-3 and gasket 75845) on a scheduled basis: low-hour aircraft must replace before 600 total flight hours, higher-hour aircraft within 200 hours, and thereafter every 600 hours. It’s intended to prevent exhaust failures, engine power loss, and carbon monoxide cabin leaks, and follows Lycoming Service Bulletin No. 395."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-31-53-exhaust-transition-coupling-retirement-life","history":"/api/acts/ad-pa-31-53-exhaust-transition-coupling-retirement-life/history","analysis":"/api/acts/ad-pa-31-53-exhaust-transition-coupling-retirement-life/analysis","conflicts":"/api/acts/ad-pa-31-53-exhaust-transition-coupling-retirement-life/conflicts","importantCases":"/api/acts/ad-pa-31-53-exhaust-transition-coupling-retirement-life/important-cases","documents":"/api/acts/ad-pa-31-53-exhaust-transition-coupling-retirement-life/documents"}}