{"id":"F2006B04762","name":"AD/BN-2/50 - Tailplane Skin and Structure - Inspection and Rectification","slug":"ad-bn-2-50-tailplane-skin-and-structure-inspection-and-rectification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44526,"registerId":"commonwealth-F2006B04762-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BN-2/50 - Tailplane Skin and Structure - Inspection and Rectification","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-2/50 Tailplane Skin and Structure - Inspection\n\nand Rectification\n\n\n7/85 DM\n\n \n\nApplicability: All models.\n\n \n\nDocument: Pilatus Britten-Norman S.B. BN-2/SB.131 Issue 2.\n\n \n\nCompliance: Within 100 hours time in service after 31 July 1985 or at the next scheduled inspection for Maintenance Release issue after 31 July 1985 whichever is the later, and thereafter at intervals not exceeding 500 hours time in service.\n\n \n\nBackground: The manufacturer has received reports of some instances of deterioration of tailplane riveting and internal rib structure.\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":true,"description":"The directive makes mandatory the inspections and rectification procedures set out in the manufacturer's service bulletin. The source text shows the manufacturer reported deterioration (\"Background\") and issued a service bulletin (\"Document\"); the AD imposes a regulatory compliance schedule and recurring inspection interval (\"Compliance\"), thereby converting manufacturer guidance into a mandatory regulatory requirement."},"complexity_factors":["Narrow technical scope (tailplane skin and internal rib structure) and single aircraft family (BN‑2 series) (\"Applicability\").","Clear, time‑based compliance schedule with an initial window and recurring 500‑hour intervals (\"Compliance\").","Dependence on an external technical document (Pilatus BN‑2/SB.131 Issue 2) for inspection and rectification details (\"Document\"), which requires access to and interpretation of manufacturer guidance.","Operational scheduling complexity created by the \"whichever is the later\" condition between a 100‑hour window and the next Maintenance Release inspection (\"Compliance\").","Technical judgement required by maintenance personnel to identify deterioration and determine rectification, creating reliance on skilled labour and possible variation in practical application (implied by reliance on the service bulletin)."],"plain_english_summary":"This airworthiness directive requires owners and operators of Pilatus Britten‑Norman BN‑2 series aeroplanes to carry out inspections of the tailplane skin and internal rib structure and to carry out any repairs found necessary, following the procedures set out in Pilatus Britten‑Norman Service Bulletin BN‑2/SB.131 Issue 2. (See: \"Applicability\" and \"Document\").\n\nWhat the instrument changes mechanically\n- It converts a manufacturer's service bulletin into a mandatory inspection and rectification requirement for the specified aeroplanes. The operator must inspect within a specified initial window and then at regular recurring intervals, and must rectify defects identified by those inspections. (See: \"Compliance\" and \"Document\").\n\nWho is affected\n- All operators and owners of Pilatus Britten‑Norman BN‑2 series aeroplanes (\"Applicability\").\n- Maintenance organisations and technicians who perform airframe inspections and repairs, because the work must be executed in accordance with the referenced service bulletin (\"Document\").\n\nWhy it matters (stated purpose and practical implications)\n- The stated reason for the directive is that the manufacturer reported instances of deterioration of tailplane riveting and internal rib structure (\"Background\"). The directive's mechanically stated effect is to require timing‑specific inspections and rectification to address that condition.\n\nCosts, incentives and compliance mechanics\n- Who pays: the owner/operator pays for inspection labour, parts and any rectification work required. Maintenance providers receive the work and invoice the operator.\n- Timing and scheduling burden: inspections must be done \"within 100 hours time in service after 31 July 1985 or at the next scheduled inspection for Maintenance Release issue after 31 July 1985 whichever is the later,\" and then at intervals not exceeding 500 hours time in service (\"Compliance\"). That creates an initial deadline and a recurring inspection cadence that operators must track against aircraft hours and maintenance release schedules.\n- Operational impact: the inspections and any rectification will use maintenance resources and may cause aircraft downtime while work is performed. The directive specifies inspection frequency but delegates technical detail of inspection and rectification methods to the referenced service bulletin (\"Document\").\n\nDelegation and discretion\n- The directive requires compliance with a named service bulletin (Pilatus BN‑2/SB.131 Issue 2) rather than prescribing detailed steps directly within the directive. This delegates the technical content of inspections and repairs to the manufacturer's document (\"Document\").\n- The directive itself does not set out enforcement procedures or penalty mechanics; it is issued under the Civil Aviation Safety Authority framework (header). Practical enforcement, interpretation of compliance and acceptance of rectification work will therefore rely on CASA practice and maintenance certification processes implicit in the regulatory framework.\n\nTrade‑offs and implementation risks\n- Trade‑offs: the directive increases short‑term maintenance costs and scheduling needs for affected operators in return for periodic checks intended to detect and correct structural deterioration early (\"Background\" and \"Compliance\").\n- Implementation risks: correct identification of the applicable compliance window (the 100‑hour initial window versus \"next scheduled inspection for Maintenance Release\"), accurate hour‑tracking, and consistent application of the service bulletin's technical instructions are necessary to be compliant. If rectification requirements are significant, operators face higher repair costs and more downtime.\n\nNet behavioural effect\n- Operators must add a recurring inspection task into maintenance planning and budget for possible repairs. Maintenance providers must be prepared to perform the inspections and rectification in accordance with the referenced service bulletin.\n\nSource citations: header (issuing authority), \"Applicability\", \"Document\", \"Compliance\", \"Background\"."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue airworthiness directive focused specifically on tailplane inspections for one aircraft series. It has not expanded beyond its original safety purpose."},"complexity_factors":["Single, specific aircraft type (Pilatus Britten-Norman BN-2 series)","Only one technical reference document (Service Bulletin BN-2/SB.131 Issue 2)","Simple compliance schedule with two clear time triggers (initial + recurring)","No defined terms section","No cross-references to other legislation or regulations","Straightforward single-issue scope (tailplane inspection only)","Background explanation provided in plain language"],"plain_english_summary":"This is an **Airworthiness Directive** (AD) — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA). It requires owners and operators of **Pilatus Britten-Norman BN-2 series aircraft** (a type of small twin-engine plane) to inspect the tailplane (the horizontal stabiliser at the back of the aircraft) for structural problems.\n\n**What must be done:**\n- **Inspect** the tailplane skin and internal structure for deteriorating rivets and damaged ribs\n- **Fix** any problems found (rectification)\n\n**When it must be done:**\n- First inspection: within 100 flying hours after 31 July 1985, or at the next scheduled maintenance check — whichever comes later\n- **Repeat** the inspection every 500 flying hours thereafter\n\n**Why it matters:**\nThe manufacturer reported cases where tailplane rivets and internal ribs were deteriorating. This could weaken the aircraft's control surfaces, potentially leading to loss of control. The AD ensures these problems are caught and fixed before they become dangerous.\n\n**Who it affects:**\nAnyone who owns, operates, or maintains a Pilatus Britten-Norman BN-2 aircraft in Australia."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bn-2-50-tailplane-skin-and-structure-inspection-and-rectification","history":"/api/acts/ad-bn-2-50-tailplane-skin-and-structure-inspection-and-rectification/history","analysis":"/api/acts/ad-bn-2-50-tailplane-skin-and-structure-inspection-and-rectification/analysis","conflicts":"/api/acts/ad-bn-2-50-tailplane-skin-and-structure-inspection-and-rectification/conflicts","importantCases":"/api/acts/ad-bn-2-50-tailplane-skin-and-structure-inspection-and-rectification/important-cases","documents":"/api/acts/ad-bn-2-50-tailplane-skin-and-structure-inspection-and-rectification/documents"}}