{"id":"F2006B08919","name":"AD/DH114/1 - Aerial Weak Link - Modification","slug":"ad-dh114-1-aerial-weak-link-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52469,"registerId":"commonwealth-F2006B08919-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DH114/1 - Aerial Weak Link - 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)  DH114 (Heron) Series Aeroplanes\n\n \n\nAD/DH114/1 Aerial Weak Link - Modification NK\n\nApplicability: All Series 1.\n\n \n\nDocument: 1. DH Heron Mod. No. 57; or\n\n \n\n2. ANO 105.1.14.17.5.1.\n\n \n\nCompliance: Before 1 June 1953.\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 instrument, as supplied, applies to all DH114 (Heron) Series 1 aeroplanes and prescribes a single modification to be carried out in accordance with one of two specified documents by a fixed date (Applicability; Document; Compliance). There is no indication in the text that the scope has been changed from an earlier or original instrument."},"complexity_factors":["Narrow applicability (applies only to DH114/Heron Series 1) — reduces breadth but concentrates effect (Applicability).","Compliance depends on external technical documents rather than containing instructions in the AD text, requiring operators to obtain and follow those documents (Document).","Fixed, historical compliance deadline creates scheduling pressure and a hard cut-off for action (Compliance).","Lack of technical detail in the AD itself increases reliance on maintenance providers and the referenced documents for practical implementation (Document).","Regulatory prescription of specific documents leaves little room for alternative compliance methods (Document)."],"plain_english_summary":"This Airworthiness Directive requires owners/operators of de Havilland DH114 (Heron) Series 1 aeroplanes to complete the specified “Aerial Weak Link” modification by 1 June 1953, using one of two referenced technical documents. Compliance is mandatory and time‑bound, with costs, scheduling and proof of work falling to the owner/operator and no alternative methods set out in the directive."},"kimi_summary":{"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This is a historical airworthiness directive from 1953 with a narrow, specific technical purpose (installation of a safety modification on one aircraft type). There is no evidence of scope creep; it remains a targeted safety order for a specific airframe modification."},"complexity_factors":["Extremely short document (approximately 150 words)","No defined terms section","No cross-references to other legislation beyond two alternative technical documents","Simple unconditional obligation: 'comply before date X'","Single applicability criterion ('All Series 1')","No exceptions, exemptions, or conditional logic"],"plain_english_summary":"This is an **Airworthiness Directive** (a mandatory safety order) issued by Australia's Civil Aviation Safety Authority for a specific type of aircraft: the **de Havilland DH114 Heron** (a British-made twin-engine passenger plane from the 1950s).\n\n**What it requires:**\n- **Who must comply:** Owners/operators of all Series 1 DH114 Heron aircraft\n- **What must be done:** Install a modification called an \"aerial weak link\" — a safety device designed to break away under excessive load, likely to prevent damage to the aircraft structure during aerial operations (such as banner towing or glider towing)\n- **How to do it:** Follow either:\n  - de Havilland Heron Modification No. 57, **or**\n  - Air Navigation Order 105.1.14.17.5.1 (an older UK/Australian aviation standard)\n- **Deadline:** Before 1 June 1953\n\n**Why it matters:** This directive addresses a structural safety concern. The \"weak link\" acts as a mechanical fuse — if the towed load becomes snagged or applies excessive force, the link breaks before damaging the aircraft's airframe or compromising flight safety.\n\n**Historical note:** This is a **very old directive** dating to the early 1950s, reflecting the era when the Heron was in active commercial service."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dh114-1-aerial-weak-link-modification","history":"/api/acts/ad-dh114-1-aerial-weak-link-modification/history","analysis":"/api/acts/ad-dh114-1-aerial-weak-link-modification/analysis","conflicts":"/api/acts/ad-dh114-1-aerial-weak-link-modification/conflicts","importantCases":"/api/acts/ad-dh114-1-aerial-weak-link-modification/important-cases","documents":"/api/acts/ad-dh114-1-aerial-weak-link-modification/documents"}}