{"id":"F2006B04723","name":"AD/BN-2/12 - Wing Attachment Spindles - Inspection","slug":"ad-bn-2-12-wing-attachment-spindles-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44487,"registerId":"commonwealth-F2006B04723-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BN-2/12 - Wing Attachment Spindles - Inspection","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)  Pilatus Britten-Norman BN-2 Series Aeroplanes\n\n \n\nAD/BN-2/12 Wing Attachment Spindles - Inspection NK\n\nApplicability: All models with S/Nos. C19 to C130 incorporating Modification NB/M/155. Document:               Britten-Norman SB No. BN-2/SB.25.\n\nCompliance: Within 10 hours time in service after 23 February 1970.\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":2,"scope_assessment":{"changed":false,"description":"The text of the instrument specifies a clear, limited scope: inspection of wing attachment spindles on BN‑2 aeroplanes with S/N C19–C130 incorporating Modification NB/M/155 and a compliance deadline (10 hours after 23 February 1970). The instrument itself does not indicate any expansion or reduction of that scope compared with what it sets out; no other scope changes are evident in the text provided."},"complexity_factors":["Narrow, specific applicability (single aircraft type, serial number range, and a specific modification) — (Applicability line).","Very short compliance window (10 hours time in service after a specific date) creating immediate operational scheduling pressure — (Compliance line).","Operational procedure delegated to an external document (Britten‑Norman SB No. BN-2/SB.25), so the AD itself lacks step‑by‑step detail — (Document line).","Absence of stated rationale, acceptance criteria, or corrective action in the AD text increases interpretive dependency on the service bulletin or regulator — (entire AD text shows no rationale).","Presence of the unexplained notation \"NK\" in the AD title introduces potential ambiguity in meaning or status — (AD title)."],"plain_english_summary":"What this instrument does mechanically\n\n- It requires an inspection of the wing attachment spindles on certain Pilatus Britten‑Norman BN‑2 series aeroplanes. (AD title and Applicability: \"Pilatus Britten-Norman BN-2 Series Aeroplanes\"; \"Applicability: All models with S/Nos. C19 to C130 incorporating Modification NB/M/155.\")\n- The inspection procedure or detailed steps are referenced to a manufacturer service bulletin: \"Britten-Norman SB No. BN-2/SB.25.\" (Document line.)\n- The inspection must be completed within a short, specified window: \"Within 10 hours time in service after 23 February 1970.\" (Compliance line.)\n\nWho is affected and who decides\n\n- The owners and operators of BN‑2 aircraft with the serial numbers and modification listed are directly affected; they must arrange the inspection. (Applicability line.)\n- Maintenance organisations, licensed engineers and anyone who performs aircraft maintenance on these aircraft will be engaged to carry out the inspection according to the referenced service bulletin. (Document line.)\n- The directive is presented under the Commonwealth framework for airworthiness directives and the Civil Aviation Safety Authority schedule of airworthiness directives, indicating the regulator issued the requirement. (Header: \"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 ... CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES.\")\n\nWho pays and what behaviour changes\n\n- Aircraft owners/operators bear the direct cost of the inspection and any follow‑on corrective work discovered by the inspection. (Inference from the requirement to inspect the specified aircraft: Applicability and Compliance lines.)\n- Operators must schedule and complete the inspection within the stated 10‑hour time‑in‑service window or continue operating while bearing the risk of non‑compliance with the directive. (Compliance line.)\n- Maintenance providers will be engaged to perform the inspection to the standard set out in the referenced service bulletin. (Document line.)\n\nPractical trade‑offs, compliance burden and implementation risks\n\n- Compliance burden is concentrated and immediate: each listed aircraft requires an inspection within a narrow timeframe (10 hours after the stated date). That creates a scheduling cost and possible short‑term removal from service. (Compliance line.)\n- The AD does not itself set out procedural steps, tolerances or corrective actions; it points to the service bulletin for details. This shifts technical procedural reliance to the manufacturer document (Britten‑Norman SB No. BN-2/SB.25), which may create implementation dependence on that bulletin and on availability of parts or approved procedures. (Document line.)\n- The text contains minimal operational detail and provides no explicit rationale, acceptance criteria, or exceptions. That raises the risk that operators will need to seek clarifications from the regulator or the manufacturer if the bulletin is ambiguous. (AD text: no rationale or procedural detail beyond the bulletin reference and compliance window.)\n- The header includes the notation \"NK\" after the AD title; the text does not explain that notation. That is a point of ambiguity in the instrument as published. (AD title: \"AD/BN-2/12 Wing Attachment Spindles - Inspection NK\")\n\nConcrete, source‑grounded summary\n\n- Action required: inspect wing attachment spindles on BN‑2 aircraft S/N C19–C130 incorporating Modification NB/M/155. (Applicability line.)\n- How to perform the action: follow Britten‑Norman SB No. BN-2/SB.25. (Document line.)\n- When to perform it: within 10 hours time in service after 23 February 1970. (Compliance line.)\n\nNote: The source text contains only the applicability, the document reference and the compliance timeframe. It does not state an explicit objective or the inspection steps in the instrument itself; those details are delegated to the referenced service bulletin. (Entire AD text.)"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused specifically on wing attachment spindle inspections for a narrow subset of BN-2 aircraft. It has not expanded beyond its original safety purpose. The scope remains tightly constrained to the specific structural concern identified in 1970."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 3 operative requirements: applicability criteria, reference document, and compliance deadline","No defined terms section — all terms are either common aviation terminology or reference external documents","No conditional logic, exceptions, or nested provisions","Single cross-reference to an external service bulletin (SB No. BN-2/SB.25) rather than internal legislative cross-references","Clear, unambiguous compliance deadline (10 hours time in service after fixed date)"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) under the Civil Aviation Regulations 1998.\n\n**What it does:** It requires owners and operators of specific **Pilatus Britten-Norman BN-2 aircraft** (a type of small twin-engine plane, often called the \"Islander\") to inspect the **wing attachment spindles** — the critical metal rods or pins that connect the wings to the aircraft fuselage.\n\n**Who it affects:** All BN-2 aircraft with **serial numbers C19 to C130** that have been modified with **Modification NB/M/155**.\n\n**What must be done:** Operators must follow the inspection procedure detailed in **Britten-Norman Service Bulletin No. BN-2/SB.25** within **10 hours of flying time** after 23 February 1970.\n\n**Why it matters:** Wing attachment spindles are structural components that keep the wings attached to the plane. A failure here would be catastrophic. This AD was issued to catch potential defects before they cause accidents.\n\n**Key point:** This is a **retrospective safety mandate** — it applies to existing aircraft and must be completed within a tight timeframe (10 flight hours) to ensure immediate airworthiness."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bn-2-12-wing-attachment-spindles-inspection","history":"/api/acts/ad-bn-2-12-wing-attachment-spindles-inspection/history","analysis":"/api/acts/ad-bn-2-12-wing-attachment-spindles-inspection/analysis","conflicts":"/api/acts/ad-bn-2-12-wing-attachment-spindles-inspection/conflicts","importantCases":"/api/acts/ad-bn-2-12-wing-attachment-spindles-inspection/important-cases","documents":"/api/acts/ad-bn-2-12-wing-attachment-spindles-inspection/documents"}}