{"id":"F2006B09093","name":"AD/DHC-3/7 - Engine Breather Drain Box","slug":"ad-dhc-3-7-engine-breather-drain-box","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115646,"registerId":"commonwealth-F2006B09093-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-3/7 - Engine Breather Drain Box","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)  DHC-3 (Otter) Series Aeroplanes\n\n \n\nAD/DHC-3/7 Engine Breather Drain Box NK\n\nApplicability: All models with S/Nos 1 to 73.\n\n \n\nRequirement: Action in accordance with De H Canada EB “O” No 5.\n\n \n\nNote: Canadian AD 55-6 refers.\n\n \n\nCompliance: Forthwith.\n\n \n","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue Airworthiness Directive addressing a specific technical problem on a specific aircraft type. It has not expanded beyond its original safety purpose."},"complexity_factors":["Extremely short document (under 150 words)","No defined terms section — relies entirely on external references","Single, unambiguous compliance requirement ('Action in accordance with...')","No conditional logic or nested exceptions","Cross-reference to only one external document (De Havilland Canada EB 'O' No 5)","Simple applicability test (serial number range 1-73)"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — essentially a mandatory safety order — issued by Australia's Civil Aviation Safety Authority (CASA) for a specific type of aircraft.\n\n**What it does:**\n- Requires owners and operators of **De Havilland Canada DHC-3 (Otter) series aeroplanes** with serial numbers 1 through 73 to take immediate action on the **engine breather drain box**.\n- The specific repair or inspection must follow instructions in **De Havilland Canada Engineering Bulletin \"O\" No. 5**.\n\n**Who it affects:**\n- Anyone who owns, operates, or maintains DHC-3 Otter aircraft with those specific serial numbers.\n\n**Why it matters:**\n- Airworthiness Directives are legally binding safety instructions. Non-compliance means the aircraft cannot legally fly in Australian airspace. This particular AD addresses a potential safety issue with the engine breather drain box — a component that manages oil and pressure ventilation from the engine. Problems here could lead to engine damage or failure.\n\n**Key details:**\n- **Compliance deadline:** \"Forthwith\" — meaning immediately, without delay.\n- **Related document:** Canadian Airworthiness Directive 55-6 also covers this issue, suggesting it originated from Canadian aviation authorities and has been adopted in Australia."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The instrument itself provides no indication that its scope has been altered from an earlier version. It applies to DHC-3 series aeroplanes with serial numbers 1 to 73, mandates action per De Havilland Canada EB \"O\" No. 5, and requires compliance forthwith. There is nothing in the text to suggest an expansion or narrowing of scope relative to any prior instrument; the AD instead cross-references a manufacturer bulletin and a related Canadian AD for technical detail (see \"Applicability\", \"Requirement\", \"Note\", \"Compliance\")."},"complexity_factors":["Short, single-issue directive: the AD is brief and focused on one component (Engine Breather Drain Box) which lowers procedural complexity (see title and Requirement).","External technical reference: required action is defined by De Havilland Canada EB \"O\" No. 5 rather than spelled out in the AD, increasing practical complexity because the EB must be obtained and followed (\"Requirement\").","Immediate compliance: the AD requires action \"forthwith\", which raises operational urgency and scheduling complexity for operators (\"Compliance\").","Limited applicability by serial number: scope is confined to DHC-3 S/Ns 1–73, which simplifies identification but requires checking individual aircraft records (\"Applicability\").","Cross-jurisdictional linkage: the AD notes a related Canadian AD (55-6), creating a need to consult additional regulatory material for context (\"Note\")."],"plain_english_summary":"This airworthiness directive mandates immediate compliance by owners/operators of De Havilland Canada DHC‑3 (Otter) aircraft, serial numbers 1–73, to obtain and implement De Havilland Canada Emergency Bulletin \"O\" No. 5. \n\nCosts, technical steps and timing fall to the operators (who must prioritise and may incur downtime), and the AD defers the specific corrective method to the manufacturer’s bulletin; it also notes a related Canadian AD."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-3-7-engine-breather-drain-box","history":"/api/acts/ad-dhc-3-7-engine-breather-drain-box/history","analysis":"/api/acts/ad-dhc-3-7-engine-breather-drain-box/analysis","conflicts":"/api/acts/ad-dhc-3-7-engine-breather-drain-box/conflicts","importantCases":"/api/acts/ad-dhc-3-7-engine-breather-drain-box/important-cases","documents":"/api/acts/ad-dhc-3-7-engine-breather-drain-box/documents"}}