{"id":"F2006B05783","name":"AD/PA-31/78 Amdt 5 - Turbocharger Exhaust Couplings","slug":"ad-pa-31-78-amdt-5-turbocharger-exhaust-couplings","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":135664,"registerId":"commonwealth-F2006B05783-current","compilationNumber":null,"startDate":"2026-04-03","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-31/78 Amdt 5 - Turbocharger Exhaust Couplings","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nPiper PA-31 Series Aeroplanes\n\nAD/PA-31/78\n\nAmdt 5\n\n  \nTurbocharger Exhaust Couplings 8/86 DM\n\nApplicability: Model PA-31 & PA31-325 with S/Nos. 31-2 to 31-8312019 Model PA-31-350 with S/Nos. 31-5001 to 31-8452021 Model PA-31-350T-1020 with S/Nos. 31-8253001 to 31-8553002.\n\nRequirement: Action in accordance with Piper SB No. 644D. Compliance: Part I of Requirement Document:\n\nUnless already accomplished in accordance with the previous issue of this Directive initially inspect within 10 hours time in service after 31 March 1986. If coupling is Piper part number 555-511 or 555-366 (segmented type), inspect every 100 hours time in service following initial inspection, and replace prior to 1000 hours time in service.\n\nPart II of Requirement:\n\nCompliance relieves the repetitive 100 hour inspection intervals and 1000 hour replacement period required by Part I of the Requirement Document.\n\nPart III of Requirement Document:\n\nFor those aircraft which have had P/N 557-584 and 557-369 clamps fitted; within 10 hours time in service after 31 August 1986.\n\nBackground: The manufacturer has made available a heavy-duty, field tested turbocharger exhaust coupling, that when installed, relieves the repetitive inspection intervals and replacement period required previously. The amendment requires an additional inspection when installing Part No. 557-584 and 557-369 clamps.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":2801},"content_quality":"ok","complexity_score":4,"scope_assessment":{"changed":true,"description":"This amendment expands the original directive by adding Part II (which provides relief from repetitive inspections for operators who upgrade to heavy-duty couplings) and Part III (which introduces a new inspection requirement for aircraft fitted with specific replacement clamp part numbers)."},"complexity_factors":["Three distinct compliance paths (Part I, II, and III) with interdependent requirements","Specific aircraft serial number ranges across four model variants","Four different part numbers (555-511, 555-366, 557-584, 557-369) subject to different regulatory treatment","Dual time-measurement systems: calendar deadlines and 'hours time in service'","Cross-reference to external manufacturer document (Piper SB No. 644D)"],"plain_english_summary":"This airworthiness directive mandates safety inspections for turbocharger exhaust couplings on specific Piper PA-31 aircraft models.\n\n**Who it affects**: Owners and operators of Piper PA-31, PA-31-325, PA-31-350, and PA-31-350T-1020 aircraft within specified serial number ranges.\n\n**What it requires**:\n- **Part I**: Aircraft with original segmented couplings (part numbers 555-511 or 555-366) must undergo inspections every 100 flight hours, with replacement required before reaching 1,000 flight hours.\n- **Part II**: Operators can be exempted from repetitive inspections by installing heavy-duty couplings as specified in the manufacturer's Service Bulletin 644D.\n- **Part III**: Aircraft fitted with specific replacement clamps (part numbers 557-584 or 557-369) require an additional inspection within 10 flight hours of installation.\n\n**Why it matters**: Defective exhaust couplings can fail in flight, potentially causing loss of engine power or fire hazards. The directive allows operators to choose between ongoing inspections or a one-time upgrade to heavier-duty components."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-31-78-amdt-5-turbocharger-exhaust-couplings","history":"/api/acts/ad-pa-31-78-amdt-5-turbocharger-exhaust-couplings/history","analysis":"/api/acts/ad-pa-31-78-amdt-5-turbocharger-exhaust-couplings/analysis","conflicts":"/api/acts/ad-pa-31-78-amdt-5-turbocharger-exhaust-couplings/conflicts","importantCases":"/api/acts/ad-pa-31-78-amdt-5-turbocharger-exhaust-couplings/important-cases","documents":"/api/acts/ad-pa-31-78-amdt-5-turbocharger-exhaust-couplings/documents"}}