{"id":"F2006B08831","name":"AD/DC4/25 - Spar Web - Modification","slug":"ad-dc4-25-spar-web-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52276,"registerId":"commonwealth-F2006B08831-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DC4/25 - Spar Web - 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/DC4/25 Spar Web - Modification NK\n\nDocument: 1. Douglas SB (C54) No. 205; or\n\n \n\n2. FAA AD 46-27-1; or\n\n \n\n3. ANOs Part 100, Appendix “A” Notice No. 7/25; or 4. ANO 105.1.16.2.5.24.\n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\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 narrow, technical airworthiness directive focused on a specific structural modification for a single aircraft type. It represents the standard, original purpose of such directives — mandating safety modifications based on manufacturer service bulletins and foreign aviation authority directives."},"complexity_factors":["Single, specific technical requirement (spar web modification)","Only 4 alternative compliance documents referenced","No defined terms section","No conditional logic or exceptions","Extremely short document (essentially a reference to external technical standards)","Applies to single aircraft type (Douglas DC-4 series)"],"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 a specific **modification to the spar web** (a structural component of the aircraft's wing) on DC-4 aeroplanes.\n- The directive references four alternative technical documents that owners/operators can follow to complete this modification:\n  1. Douglas Service Bulletin (C54) No. 205\n  2. FAA Airworthiness Directive 46-27-1 (American aviation safety rule)\n  3. Australian National Operations (ANO) Part 100, Appendix \"A\" Notice No. 7/25\n  4. ANO 105.1.16.2.5.24\n\n**Who it affects:**\n- Owners and operators of Douglas DC-4 aircraft registered in Australia.\n- Maintenance organisations servicing these vintage aircraft.\n\n**Why it matters:**\nAirworthiness Directives are legally binding safety instructions. This AD addresses a potential structural weakness in the wing spar web that could affect flight safety. Compliance is mandatory — aircraft cannot legally fly unless this modification is completed (or an alternative approved by CASA is in place)."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The schedule entry is a concise directive that requires a spar-web modification for Douglas DC4 series aircraft by reference to one of four named technical documents. The entry itself does not state any change of scope from an earlier instrument or an original intent; it lists acceptable documents only and does not indicate any extension or narrowing of scope within the text provided."},"complexity_factors":["Directive references external technical documents rather than reproducing technical steps, requiring operators to obtain and read additional material (Document list: Douglas SB (C54) No. 205; FAA AD 46-27-1; ANOs Part 100 Appendix A Notice No. 7/25; ANO 105.1.16.2.5.24).","Multiple alternative references are acceptable, creating a choice for the operator about which set of instructions to apply.","The subject matter (spar web modification) is technical and requires qualified maintenance personnel to perform the work to the standards in the chosen reference.","Compliance imposes operational tasks (maintenance scheduling, possible procurement of parts) that vary depending on the chosen reference and aircraft condition.","The directive sits within the Civil Aviation Regulations Part 39 enforcement framework, so legal compliance is obligatory even though the entry itself is short on procedural detail."],"plain_english_summary":"This Civil Aviation Safety Authority airworthiness directive requires Douglas DC‑4 series aircraft to receive a specified \"Spar Web\" modification. It does not include technical steps itself but mandates compliance by following one of four named technical documents.\n\nOperators must obtain and apply one of those listed references, bear the cost of parts and labour, and complete the modification to meet the regulatory requirement."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dc4-25-spar-web-modification","history":"/api/acts/ad-dc4-25-spar-web-modification/history","analysis":"/api/acts/ad-dc4-25-spar-web-modification/analysis","conflicts":"/api/acts/ad-dc4-25-spar-web-modification/conflicts","importantCases":"/api/acts/ad-dc4-25-spar-web-modification/important-cases","documents":"/api/acts/ad-dc4-25-spar-web-modification/documents"}}