{"id":"F2006B05753","name":"AD/PA-31/49 - Elevator Hinge System - Modification","slug":"ad-pa-31-49-elevator-hinge-system-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":135599,"registerId":"commonwealth-F2006B05753-current","compilationNumber":null,"startDate":"2026-04-03","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-31/49 - Elevator Hinge System - Modification","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-31/49 Elevator Hinge System - Modification 8/76\n\nApplicability: All model PA-31T with S/Nos. 31T-7400001 to 31T-7620039. Document:  Piper SB No. 504.\n\nCompliance: Within 100 hours time in service after 31 August 1976.\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":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":2762},"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This directive maintains its original narrow scope. It applies only to specific serial numbers of the Piper PA-31T model and mandates a single specific modification to the elevator hinge system. There is no indication of scope expansion beyond the original safety defect it was issued to correct."},"complexity_factors":["Extremely short text (under 150 words)","No interpretation section or defined terms","Single, unambiguous applicability criterion (specific serial number range)","Only one external cross-reference (Piper SB No. 504)","No conditional logic, exceptions, or nested requirements"],"plain_english_summary":"This Airworthiness Directive mandates a safety modification for specific Piper aircraft to fix potential problems with the elevator hinge system (the parts that allow the tail elevator to pivot, controlling the plane's up-and-down movement).\n\n**Who it affects**\nOwners and operators of Piper PA-31T aeroplanes with serial numbers between 31T-7400001 and 31T-7620039.\n\n**What you must do**\nModify the elevator hinge system according to the instructions in **Piper Service Bulletin No. 504**.\n\n**When**\nComplete the modification within 100 hours of flight time (time in service) after **31 August 1976**.\n\n**Why it matters**\nThis ensures the elevator hinge system meets safety standards and prevents potential control failures that could affect the aircraft's ability to climb or descend safely."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-31-49-elevator-hinge-system-modification","history":"/api/acts/ad-pa-31-49-elevator-hinge-system-modification/history","analysis":"/api/acts/ad-pa-31-49-elevator-hinge-system-modification/analysis","conflicts":"/api/acts/ad-pa-31-49-elevator-hinge-system-modification/conflicts","importantCases":"/api/acts/ad-pa-31-49-elevator-hinge-system-modification/important-cases","documents":"/api/acts/ad-pa-31-49-elevator-hinge-system-modification/documents"}}