{"id":"F2006B08825","name":"AD/DC4/2 - Undercarriage Door Stud - Replacement","slug":"ad-dc4-2-undercarriage-door-stud-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52258,"registerId":"commonwealth-F2006B08825-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DC4/2 - Undercarriage Door Stud - 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)  Douglas DC4 Series Aeroplanes\n\n \n\nAD/DC4/2 Undercarriage Door Stud - Replacement NK\n\nDocument: 1. Douglas SB (C54) No. 275 dated 21 January 1946; or\n\n \n\n2. FAA AD 46-11-3; or\n\n \n\n3. ANO 105.1.16.2.5.1.\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":3,"scope_assessment":{"changed":false,"description":"The instrument, as presented, sets a specific, limited scope: replacement of the undercarriage door stud on Douglas DC‑4 series aeroplanes by following one of three listed documents (Douglas SB No. 275; FAA AD 46‑11‑3; ANO 105.1.16.2.5.1). There is no indication in the provided text that the scope has been expanded or narrowed from that operative requirement."},"complexity_factors":["Short, focused directive with a single operative requirement (replacement of undercarriage door stud).","Primary complexity arises from references to external technical documents rather than inclusion of technical steps in the AD itself (Document: 1, 2, 3).","Technical aviation terminology (undercarriage door stud) requires specialist maintenance knowledge to execute.","Enforcement under Civil Aviation Regulations Part 39 adds regulatory context but the AD text shown does not include compliance deadlines, inspection intervals, or detailed procedures, which reduces internal complexity but transfers complexity to the referenced documents."],"plain_english_summary":"This airworthiness directive requires owners/operators of Douglas DC‑4 series aeroplanes to replace the undercarriage (landing‑gear) door stud, complying by reference to one of three specified technical documents. The Civil Aviation Safety Authority enforces the rule; costs for parts, labour and downtime fall to the operator. The AD sets a clear compliance standard but relies on external historical/third‑party instructions for the detailed procedure."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive focused specifically on a single mechanical component (undercarriage door studs) for a specific aircraft type (DC-4). It has not expanded beyond its original narrow technical purpose."},"complexity_factors":["Extremely short document (single page)","Only one substantive requirement (replace the stud)","No defined terms section","No conditional logic or exceptions","Simple reference to three alternative compliance documents","No cross-references to other legislation beyond the cited documents"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** issued by Australia's Civil Aviation Safety Authority (CASA) for **Douglas DC-4 series aircraft**.\n\n**What it does:**\n- Requires the **replacement of undercarriage door studs** on these vintage aeroplanes.\n- An \"undercarriage\" is the landing gear (wheels and struts) that supports the aircraft on the ground.\n- The \"door stud\" is a small but critical fastener that holds the landing gear doors in place.\n\n**Why it matters:**\n- If these studs fail, the landing gear doors could detach during flight or landing, creating a serious safety hazard.\n- This directive ensures operators of these 1940s-era aircraft maintain them to modern safety standards.\n\n**Who it affects:**\n- Owners and operators of Douglas DC-4 aircraft still flying in Australia (mostly historical/vintage aircraft).\n- Maintenance engineers working on these planes.\n\n**Compliance documents:**\nOperators must follow one of three technical documents when doing the replacement:\n1. Douglas Service Bulletin No. 275 (January 1946), or\n2. FAA Airworthiness Directive 46-11-3 (American equivalent), or\n3. ANO 105.1.16.2.5.1 (an older Australian aviation order)."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dc4-2-undercarriage-door-stud-replacement","history":"/api/acts/ad-dc4-2-undercarriage-door-stud-replacement/history","analysis":"/api/acts/ad-dc4-2-undercarriage-door-stud-replacement/analysis","conflicts":"/api/acts/ad-dc4-2-undercarriage-door-stud-replacement/conflicts","importantCases":"/api/acts/ad-dc4-2-undercarriage-door-stud-replacement/important-cases","documents":"/api/acts/ad-dc4-2-undercarriage-door-stud-replacement/documents"}}