{"id":"F2006B08815","name":"AD/DC4/10 - Hydraulic Accumulator - Replacement","slug":"ad-dc4-10-hydraulic-accumulator-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52223,"registerId":"commonwealth-F2006B08815-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DC4/10 - Hydraulic Accumulator - 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/DC4/10 Hydraulic Accumulator - Replacement NK\n\nDocument: 1. Douglas SB (DC4) No. 9 dated 13 December 1946; or\n\n \n\n2. FAA AD 47-2-3; or\n\n \n\n3. ANO 105.1.16.2.5.9, Issue 2.\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 directive retains a narrowly focused scope: replacement of the hydraulic accumulator on Douglas DC4 series aeroplanes by following one of the three referenced documents (Douglas SB No. 9; FAA AD 47-2-3; ANO 105.1.16.2.5.9). The source text provides no indication that the scope has been expanded or altered from that stated requirement (AD/DC4/10)."},"complexity_factors":["Very short primary text that delegates technical detail to external documents (Douglas SB No. 9; FAA AD 47-2-3; ANO 105.1.16.2.5.9) increases practical complexity for operators who must retrieve and follow those sources (AD/DC4/10).","Applicability limited to a small, identifiable population (Douglas DC4 series), making substantive impact concentrated but administratively simple.","Absence of explicit compliance timing, cost estimates, or enforcement mechanism in the directive text creates uncertainty about implementation burden.","References include legacy documents (one dated 1946), which can complicate parts availability, contemporary approval of procedures, and maintenance planning.","Legal and operational decisions split between the regulator (which prescribes the requirement) and operators/maintenance organisations (which choose which referenced document to apply), requiring coordination."],"plain_english_summary":"AD/DC4/10 mandates replacement of the hydraulic accumulator on Douglas DC‑4 series aircraft, requiring owners, operators and their maintenance organisations to carry out the work using one of three referenced legacy documents. Compliance is mandatory and shifts parts, labour and downtime costs to operators; the AD delegates technical detail to older service/airworthiness materials, which may raise practical and cost burdens for vintage‑aircraft operators."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This appears to be a complete, standalone airworthiness directive. It has not expanded beyond its original purpose of mandating a specific safety modification for DC-4 aircraft. The scope remains tightly focused on the hydraulic accumulator replacement."},"complexity_factors":["Extremely short document — essentially a single paragraph with references","Only one substantive requirement (replace the hydraulic accumulator)","No defined terms section","No conditional logic or exceptions","Cross-references are simple citations to three external technical documents rather than internal legislative cross-references","No procedural steps or compliance timelines specified in the text provided"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:** It requires owners and operators of **Douglas DC-4 series aeroplanes** to replace the **hydraulic accumulator** — a component that stores pressurised hydraulic fluid for the aircraft's control systems. The directive references three technical documents that specify how this replacement must be done:\n- A 1946 Douglas service bulletin\n- An old American FAA safety directive from 1947\n- A former Australian aviation order\n\n**Who it affects:** Anyone who owns, operates, or maintains a Douglas DC-4 aircraft in Australia. These are vintage four-engine propeller aircraft from the 1940s, now mostly used for historical or cargo purposes.\n\n**Why it matters:** Hydraulic accumulators are critical safety components. If they fail, pilots could lose hydraulic pressure needed for flight controls, landing gear, or brakes. This AD ensures these ageing aircraft remain airworthy by mandating replacement of a specific part before it can fail."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dc4-10-hydraulic-accumulator-replacement","history":"/api/acts/ad-dc4-10-hydraulic-accumulator-replacement/history","analysis":"/api/acts/ad-dc4-10-hydraulic-accumulator-replacement/analysis","conflicts":"/api/acts/ad-dc4-10-hydraulic-accumulator-replacement/conflicts","importantCases":"/api/acts/ad-dc4-10-hydraulic-accumulator-replacement/important-cases","documents":"/api/acts/ad-dc4-10-hydraulic-accumulator-replacement/documents"}}