{"id":"F2006B08878","name":"AD/DH 104/35 Amdt 1 - Aircraft Life Extension","slug":"ad-dh-104-35-amdt-1-aircraft-life-extension","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52303,"registerId":"commonwealth-F2006B08878-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DH 104/35 Amdt 1 - Aircraft Life Extension","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)  DH 104 (Dove) Series Aeroplanes\n\n \n\n# AD/DH 104/35\n\nAmdt 1\n\nApplicability: All models.\n\n# Aircraft Life Extension 7/77\n\n \n\nDocument: British Aerospace TNS Dove (104) No. 240 Issue 2.\n\n \n\nCompliance: As detailed in the requirement document. NOTE: Wing spar boom safe lives are detailed in the current issue of AD/DH 104/5. the manufacturer has advised that the aircraft life cannot be extended beyond two wing spar boom lifetimes.\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 amendment to an existing airworthiness directive. It maintains the original scope (life extension limits for DH 104 aircraft) and does not expand beyond the specific safety purpose of preventing structural fatigue in aging airframes."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 1 defined reference (the British Aerospace technical document)","Single cross-reference to related directive AD/DH 104/5","No conditional logic or nested exceptions — straightforward applicability to 'all models'","Simple compliance structure: follow the external technical document","Single substantive limitation (two wing spar boom lifetime cap)"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety instruction issued by Australia's Civil Aviation Safety Authority (CASA) that applies to specific aircraft.\n\n**Which aircraft:** All models of the **de Havilland DH 104 \"Dove\"** series aeroplanes (a British twin-engine aircraft from the 1940s-60s).\n\n**What it does:** This directive (Amendment 1 to AD/DH 104/35) sets rules for **extending how long these aircraft can safely fly** beyond their originally designed lifespan. It references a technical document from British Aerospace (Technical Note Sheet Dove No. 240, Issue 2) that contains the specific engineering requirements.\n\n**Key safety limits:**\n- **Wing spar booms** (the main structural beams running through the wings) have strict \"safe life\" limits — these are set out in a separate directive (AD/DH 104/5)\n- **Hard ceiling:** The manufacturer has advised that no matter what maintenance you do, you cannot extend the aircraft's total life beyond **two wing spar boom lifetimes**\n\n**Who must comply:** Owners and operators of DH 104 Dove aircraft must follow the requirements in the referenced British Aerospace document.\n\n**Why it matters:** This prevents structural fatigue failures in aging aircraft. The wing spar is literally what holds the wings on — if it fails, the wing falls off. These rules ensure old Doves aren't flown beyond safe structural limits, even with good maintenance."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The instrument itself does not state any change of scope. It applies to all DH 104 (Dove) models and requires compliance with the referenced manufacturer requirement document; it also records the manufacturer’s limit on life extensions (no extension beyond two wing spar boom lifetimes). No narrowing or broadening of applicability is recorded in the text provided (sources: \"Applicability: All models\"; \"Document...\"; \"NOTE: Wing spar boom safe lives...\")."},"complexity_factors":["Cross-reference to multiple external documents: the manufacturer requirement document (British Aerospace TNS Dove No. 240 Issue 2) and AD/DH 104/5 for wing spar boom safe lives (source: \"Document...\"; \"NOTE: Wing spar boom safe lives...\").","Technical content omitted from the directive itself (\"Compliance: As detailed in the requirement document\"), requiring readers to obtain and interpret separate technical material.","An absolute operational limit provided by the manufacturer (no life extension beyond two wing spar boom lifetimes) that has direct economic consequences for operators (source: \"the manufacturer has advised...\").","Regulatory enforcement is mandatory but the directive delegates detailed methods and numeric limits to external documents, creating implementation dependencies and potential administrative friction.","Potential ambiguity for operators about where to find detailed procedures and how to obtain approvals or variances because the directive does not enumerate inspection/approval steps in-line."],"plain_english_summary":"This directive mandates how owners/operators of all de Havilland DH 104 (Dove) aircraft may extend an airframe’s authorised operational life: they must follow the manufacturer’s requirement document (British Aerospace TNS Dove No.240 Issue 2) and comply with wing-spar safe-life limits in AD/DH 104/5. It prevents life extensions beyond two wing‑spar boom lifetimes, making those external documents essential for compliance, costs, and retirement planning."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dh-104-35-amdt-1-aircraft-life-extension","history":"/api/acts/ad-dh-104-35-amdt-1-aircraft-life-extension/history","analysis":"/api/acts/ad-dh-104-35-amdt-1-aircraft-life-extension/analysis","conflicts":"/api/acts/ad-dh-104-35-amdt-1-aircraft-life-extension/conflicts","importantCases":"/api/acts/ad-dh-104-35-amdt-1-aircraft-life-extension/important-cases","documents":"/api/acts/ad-dh-104-35-amdt-1-aircraft-life-extension/documents"}}