{"id":"F2006B08954","name":"AD/DH114/42 - Nose Gear Inner Casing - Inspection and Replacement","slug":"ad-dh114-42-nose-gear-inner-casing-inspection-and-replacement","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52516,"registerId":"commonwealth-F2006B08954-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DH114/42 - Nose Gear Inner Casing - Inspection and Replacement","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/DH114/42 Nose Gear Inner Casing - Inspection NK\n\nand Replacement\n\n \n\nApplicability: All models.\n\n \n\nDocument: Hawker Siddeley TNS Heron (114) No. U.17.\n\n \n\nCompliance:  Inspect casing in accordance with para. 3 of TNS No. U.17 within 50 hours time in service after 31 December 1973 and thereafter at intervals not exceeding 600 hours time in service and after any reported heavy landings.\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 discrete, single-issue safety directive focused specifically on nose gear casing inspection for one aircraft type. It has not expanded beyond its original purpose; it remains a targeted maintenance requirement issued in 1973 with no subsequent amendments visible in this version."},"complexity_factors":["Very short document (under 200 words)","Only 4 operative paragraphs (Applicability, Document reference, Compliance requirements)","No defined terms section — uses plain language and aircraft-specific references","Single compliance pathway with clear time intervals (50 hours, 600 hours)","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1998","Simple conditional trigger (after heavy landings) with no nested exceptions"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nOrders owners and operators of **DH114 Heron series aeroplanes** (a British twin-engine aircraft from the 1950s-60s) to inspect and replace the **nose gear inner casing** — a critical structural component of the front landing gear.\n\n**Who it affects:**\nAnyone who owns, operates, or maintains any model of the DH114 Heron aircraft.\n\n**What must be done:**\n- **First inspection:** Within 50 hours of flying time after 31 December 1973\n- **Ongoing inspections:** Every 600 hours of flying time thereafter\n- **Extra check:** Immediately after any heavy or hard landing\n\n**Why it matters:**\nLanding gear failures can be catastrophic. This directive prevents accidents by catching fatigue or damage in the nose gear casing before it fails. The specific technical instructions are found in a manufacturer document called \"TNS No. U.17\" (a technical notice from Hawker Siddeley, the aircraft maker).\n\n**Key point:** This is not optional. Airworthiness Directives are legally binding — ignoring them means the aircraft cannot legally fly."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text of the directive itself does not indicate a change in scope from any prior instrument. It specifies that it applies to all DH114 (Heron) models and prescribes inspection timing and triggers referencing TNS No. U.17 (Applicability; Document; Compliance). No language in the supplied text suggests an expansion or limitation of scope beyond those explicit terms."},"complexity_factors":["Dependence on an external technical document (Hawker Siddeley TNS Heron (114) No. U.17, paragraph 3) for the detailed inspection procedure increases practical complexity and creates an implementation dependency (Document).","Multiple temporal requirements: an initial deadline (within 50 hours after 31 Dec 1973) and a recurring interval (every 600 hours) require scheduling and recordkeeping (Compliance).","Event-triggered compliance: inspections also required after any reported heavy landings, which introduces a non-scheduled compliance trigger and potential disputes over what constitutes a 'heavy landing' (Compliance).","Scope breadth: applicability to all models of the DH114 series expands the universe of affected aircraft and operators and may require varying maintenance logistics across operators (Applicability).","Replacement outcome unspecified: the AD mandates inspection and replacement where indicated but does not itself define acceptance/rejection criteria or who approves replacements beyond the referenced technical note, creating interpretive or enforcement ambiguity (Document; Compliance)."],"plain_english_summary":"This directive requires operators and maintainers of DH114 (Heron) aircraft to inspect the nose‑gear inner casing per paragraph 3 of Hawker Siddeley TNS Heron (114) No. U.17 and replace parts as the inspection dictates. Inspections begin within 50 hours TIS after 31 Dec 1973, recur every 600 hours TIS, and follow any heavy landing. It protects airworthiness but imposes recurring inspection, repair costs and downtime on aircraft owners/operators."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dh114-42-nose-gear-inner-casing-inspection-and-replacement","history":"/api/acts/ad-dh114-42-nose-gear-inner-casing-inspection-and-replacement/history","analysis":"/api/acts/ad-dh114-42-nose-gear-inner-casing-inspection-and-replacement/analysis","conflicts":"/api/acts/ad-dh114-42-nose-gear-inner-casing-inspection-and-replacement/conflicts","importantCases":"/api/acts/ad-dh114-42-nose-gear-inner-casing-inspection-and-replacement/important-cases","documents":"/api/acts/ad-dh114-42-nose-gear-inner-casing-inspection-and-replacement/documents"}}