{"id":"F2006B08822","name":"AD/DC4/17 - Nose Wheel Retracting Cylinder - Modification","slug":"ad-dc4-17-nose-wheel-retracting-cylinder-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52249,"registerId":"commonwealth-F2006B08822-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DC4/17 - Nose Wheel Retracting Cylinder - 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)  Douglas DC4 Series Aeroplanes\n\n \n\nAD/DC4/17 Nose Wheel Retracting Cylinder - Modification NK\n\nDocument: 1. Douglas SB (DC4) No. 78, dated 4 May 1948 and revised 28 January 1949; or\n\n \n\n2. FAA AD 48-44-1; or\n\n \n\n3. ANO 105.1.16.2.5.16, 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 AD’s scope is aircraft-type specific (Douglas DC-4 series) and is limited to a nose wheel retracting cylinder modification. The instrument directs compliance by following one of the three listed documents. There is no indication within the AD text supplied that the scope differs from this expressed intent."},"complexity_factors":["Short primary text with no technical detail: the AD delegates all technical instructions to external documents (Document 1–3).","Multiple cross-references: compliance may follow any one of three distinct documents (Douglas SB, FAA AD, or ANO), requiring review of external material to determine exact steps.","Vintage and external sources: the listed documents include an older service bulletin and an FAA AD, potentially requiring effort to obtain and reconcile historic guidance.","Regulatory placement: issued under Part 39 (Schedule of Airworthiness Directives), so compliance is mandatory rather than advisory."],"plain_english_summary":"This AD mandates a modification to the nose‑wheel retracting cylinder on Douglas DC‑4 series aircraft. Compliance is achieved only by following one of three specified documents, which contain the required technical procedures, parts and instructions.\n\nIt affects DC‑4 owners, operators and their maintenance organisations, who must source the referenced documents, perform and record the work, and bear associated time and cost."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive from 1948 (with Australian adoption likely later). It has not expanded beyond its original narrow purpose of mandating a specific safety modification to the DC-4 nose gear."},"complexity_factors":["Extremely short document — essentially a reference to external technical standards","Only 3 defined compliance paths (the three technical documents listed)","No conditional logic, exceptions, or nested provisions","Single subject matter: one mechanical component on one aircraft type","No cross-references to other legislation beyond the enabling regulation (CAR 1998 Part 39)","Minimal procedural requirements — simply 'comply with one of these three documents'"],"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) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of **Douglas DC-4 series aircraft** to modify the **nose wheel retracting cylinder** (the hydraulic component that raises and lowers the front landing gear). The modification must follow one of three approved technical documents:\n- A Douglas Service Bulletin from 1948/1949\n- An equivalent US Federal Aviation Administration (FAA) directive\n- A UK Air Navigation Order\n\n**Who it affects:** Anyone who owns, operates, or maintains a Douglas DC-4 aircraft in Australia.\n\n**Why it matters:** Airworthiness Directives are legally binding safety fixes. If you don't comply, you cannot legally fly the aircraft. This particular AD addresses a specific mechanical issue with the nose gear — likely a design flaw or failure risk discovered in the 1940s that could affect landing gear operation."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dc4-17-nose-wheel-retracting-cylinder-modification","history":"/api/acts/ad-dc4-17-nose-wheel-retracting-cylinder-modification/history","analysis":"/api/acts/ad-dc4-17-nose-wheel-retracting-cylinder-modification/analysis","conflicts":"/api/acts/ad-dc4-17-nose-wheel-retracting-cylinder-modification/conflicts","importantCases":"/api/acts/ad-dc4-17-nose-wheel-retracting-cylinder-modification/important-cases","documents":"/api/acts/ad-dc4-17-nose-wheel-retracting-cylinder-modification/documents"}}