{"id":"F2006B04782","name":"AD/BN-2/7 - Elevator Trim System - Modification","slug":"ad-bn-2-7-elevator-trim-system-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44559,"registerId":"commonwealth-F2006B04782-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BN-2/7 - Elevator Trim System - 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)  Pilatus Britten-Norman BN-2 Series Aeroplanes\n\n \n\nAD/BN-2/7 Elevator Trim System - Modification NK\n\nApplicability: All model BN-2A with S/No. 13 and subsequent and S/Nos. 10, 11 and 12 if Mod.\n\nNB/M/134 has been incorporated.\n\n \n\nDocument: Britten-Norman Modification Leaflet BN-2/NB/M/179 Issue 2. Compliance: Within 100 hours time in service after 12 May 1969.\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 supplied text presents a discrete airworthiness directive that applies to specified BN‑2A serial numbers and prescribes a single modification leaflet with a defined compliance timeframe. The text contains no information indicating a change from an earlier or different scope; it states the applicability, the modification document to be used, and the compliance deadline. (See: Applicability; Document; Compliance)"},"complexity_factors":["Narrow, clearly defined applicability by aircraft model and serial numbers (straightforward to determine applicability). (See: Applicability)","Single prescribed compliance method (one referenced modification leaflet), reducing procedural complexity but requiring technical execution. (See: Document)","Fixed, short compliance window (100 hours time in service after a specified date) imposes scheduling pressure but is a simple deadline. (See: Compliance)","Technical implementation requires qualified maintenance resources, introducing operational and logistical complexity not expanded on in the text. (See: Document)"],"plain_english_summary":"This airworthiness directive mandates a physical modification to the elevator trim system on specified Pilatus Britten‑Norman BN‑2A aeroplanes, carried out only per Britten‑Norman Modification Leaflet BN‑2/NB/M/179 Issue 2. It applies to BN‑2A S/N 13 onward (and S/N 10–12 if Mod. NB/M/134 was fitted); owners/operators must arrange and pay for the work within 100 hours time‑in‑service after 12 May 1969. The requirement imposes scheduling, cost and maintenance burdens on affected operators."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-purpose airworthiness directive issued in 1969. It has not expanded beyond its original scope of requiring a specific safety modification to the elevator trim system on specified aircraft. The document represents the complete directive as originally intended."},"complexity_factors":["Very short document (approximately 150 words of substantive content)","Only 2 defined applicability criteria (serial number ranges plus conditional exception)","Single compliance requirement with clear deadline","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1998","No nested conditions or exceptions beyond the single 'if' clause for serial numbers 10-12","Straightforward command structure: applies to X, do Y by Z date"],"plain_english_summary":"This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires specific modifications to the elevator trim system on certain Pilatus Britten-Norman BN-2 aircraft.\n\n**What it does:**\n- Orders owners/operators of affected BN-2A model aircraft to modify their elevator trim system according to manufacturer instructions (Modification Leaflet BN-2/NB/M/179 Issue 2)\n- The elevator trim system is the control that helps pilots maintain steady flight without constantly holding the control column\n\n**Who it affects:**\n- All BN-2A aircraft with serial numbers 13 and higher\n- Serial numbers 10, 11, and 12 — but **only if** they've already had Modification NB/M/134 installed\n\n**Why it matters:**\n- Airworthiness Directives are legally binding safety requirements\n- Non-compliance means the aircraft cannot legally fly\n- This particular directive addresses potential safety issues with the elevator trim system that could affect flight control\n\n**Compliance deadline:**\n- Must be completed within 100 hours of flight time after 12 May 1969"}},"importantCases":[],"_links":{"self":"/api/acts/ad-bn-2-7-elevator-trim-system-modification","history":"/api/acts/ad-bn-2-7-elevator-trim-system-modification/history","analysis":"/api/acts/ad-bn-2-7-elevator-trim-system-modification/analysis","conflicts":"/api/acts/ad-bn-2-7-elevator-trim-system-modification/conflicts","importantCases":"/api/acts/ad-bn-2-7-elevator-trim-system-modification/important-cases","documents":"/api/acts/ad-bn-2-7-elevator-trim-system-modification/documents"}}