{"id":"F2006B05695","name":"AD/PA-31/109 - Landing Gear Upper Bearing Retaining Pins and Strut Assemblies","slug":"ad-pa-31-109-landing-gear-upper-bearing-retaining-pins-and-strut-assemblies","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":135487,"registerId":"commonwealth-F2006B05695-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/PA-31/109 - Landing Gear Upper Bearing Retaining Pins and Strut Assemblies","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\n# AD/PA-31/109 Landing Gear Upper Bearing Retaining\n\nPins and Strut Assemblies\n\nApplicability: All model PA-31 with S/Nos as listed in Piper Service Bulletin No. 779A. Requirement:               Action in accordance with Piper S.B. No 779A.\n\nNote: FAA AD 85-08-05 refers.\n\n \n\nCompliance: Within 100 hours time in service after 31 October 1985.\n\n# 8/85\n\n \n\nBackground:  Failure of landing gear upper bearing retaining pins could result in unrestricted extension of the piston tube and wheel assemblies.\n\n \n\nThis Directive requires the replacement of the retaining pins and, in addition, an inspection and replacement of the upper bearing as applicable.\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 discrete, targeted safety directive addressing a specific mechanical defect in a specific aircraft type. It has not expanded beyond its original purpose of mandating landing gear inspections and repairs."},"complexity_factors":["Very short document (under 200 words)","Only 1 defined applicability criterion (aircraft serial numbers)","Single compliance action with reference to external manufacturer document","No nested conditions or exceptions","No internal cross-references to other legislation sections","Straightforward temporal trigger (100 hours time-in-service after fixed date)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It applies to specific **Piper PA-31 series aircraft** (twin-engine planes commonly used for charter and freight work).\n\n**What it does:**\n- Requires owners/operators to replace **landing gear upper bearing retaining pins** on these aircraft\n- Also requires inspection and replacement of the **upper bearing** itself where needed\n- The work must follow **Piper Service Bulletin No. 779A** (the manufacturer's official repair instructions)\n\n**Why it matters:**\nThe retaining pins can fail. If they do, the landing gear piston tubes and wheels can extend uncontrollably — meaning the landing gear could drop unexpectedly during flight or fail to function properly when needed. This creates serious safety risks.\n\n**Who must comply:**\nAnyone operating a PA-31 aircraft with serial numbers listed in Piper Service Bulletin 779A.\n\n**When:**\nWithin 100 hours of flight time after 31 October 1985.\n\n**Key point:** This directive references an American FAA directive (AD 85-08-05), showing how Australia often adopts US safety standards for aircraft originally certified there."},"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The Directive is narrowly targeted: it applies only to PA-31 aeroplanes with serial numbers listed in Piper Service Bulletin No. 779A and requires the replacement of retaining pins and inspection/replacement of the upper bearing. Nothing in the text indicates an expansion or contraction of that target group or of the required actions beyond what is stated (Applicability; Requirement). The Directive depends on the Service Bulletin for the serial-number list and technical steps but does not change scope beyond that cross-reference."},"complexity_factors":["Short, prescriptive text with a single, clearly defined action (replacement and inspection) required","Applicability limited to specific PA-31 serial numbers listed in an external document (Piper Service Bulletin No. 779A), requiring cross-reference","Fixed compliance timeline (100 hours TIS after 31 Oct 1985) creates scheduling constraints","Relies on technical details contained in an external Service Bulletin rather than in the Directive itself","Cross-reference to an FAA airworthiness directive (FAA AD 85-08-05) for related authority/context"],"plain_english_summary":"This AD requires owners/operators of the Piper PA-31 aircraft identified by serial number in Piper Service Bulletin No. 779A to replace landing‑gear upper bearing retaining pins and inspect (replacing if needed) the upper bearing per that Service Bulletin, within 100 hours TIS after 31 October 1985.  \n\nIt aims to prevent failure that could allow uncontrolled extension of the piston tube and wheel assemblies; owners/operators bear parts, labour and downtime costs."}},"importantCases":[],"_links":{"self":"/api/acts/ad-pa-31-109-landing-gear-upper-bearing-retaining-pins-and-strut-assemblies","history":"/api/acts/ad-pa-31-109-landing-gear-upper-bearing-retaining-pins-and-strut-assemblies/history","analysis":"/api/acts/ad-pa-31-109-landing-gear-upper-bearing-retaining-pins-and-strut-assemblies/analysis","conflicts":"/api/acts/ad-pa-31-109-landing-gear-upper-bearing-retaining-pins-and-strut-assemblies/conflicts","importantCases":"/api/acts/ad-pa-31-109-landing-gear-upper-bearing-retaining-pins-and-strut-assemblies/important-cases","documents":"/api/acts/ad-pa-31-109-landing-gear-upper-bearing-retaining-pins-and-strut-assemblies/documents"}}