{"id":"F2006B04738","name":"AD/BN-2/27 - Aileron Mass Balance Attachment - Inspection and Modification","slug":"ad-bn-2-27-aileron-mass-balance-attachment-inspection-and-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44502,"registerId":"commonwealth-F2006B04738-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BN-2/27 - Aileron Mass Balance Attachment - Inspection and 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-2/27 Aileron Mass Balance Attachment - Inspection\n\nand Modification\n\n\n12/73\n\n \n\nApplicability: All models.\n\n \n\nDocument: Britten Norman SB BN-2/SB.67. Compliance:  As per requirement document.\n\nNote: Daily inspection may be performed and certified by the pilot.\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 supplied directive, as written, applies to all BN-2 models and requires compliance with Britten Norman SB BN-2/SB.67. No earlier or alternative scope is provided in the supplied text, so there is no basis in this document to conclude the scope has changed from any prior instrument."},"complexity_factors":["Reference to an external technical document (Britten Norman SB BN-2/SB.67) for substantive requirements rather than specifying details in the AD","Broad applicability to all BN-2 models (no model-specific tailoring)","Ambiguous phrase \"As per requirement document\" creates dependence on the bulletin for scope, timing, parts, and labour","A specific procedural flexibility: pilots may perform and certify a daily inspection (creates mixed compliance paths)","Limited detail in the AD itself increases implementation and verification tasks for operators and regulators"],"plain_english_summary":"This directive makes compliance with Britten Norman SB BN-2/SB.67 mandatory: BN-2 series aileron mass-balance attachments must be inspected and modified as directed, and the AD applies to all BN-2 models. \n\nIt affects BN-2 owners/operators, maintenance organisations, and pilots (pilots may perform and certify a permitted daily inspection). Costs and implementation (parts, tooling, downtime) fall to operators and their maintenance providers."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive focused specifically on aileron mass balance attachments for one aircraft series. It has not expanded beyond its original technical safety purpose."},"complexity_factors":["Extremely short document (approximately 150 words)","Only 1 defined term implicitly referenced (the service bulletin)","No cross-references to other legislation beyond the parent Civil Aviation Regulations 1998","No conditional logic or nested exceptions — simple applicability statement ('All models')","Single compliance pathway (follow the service bulletin)","Minimal regulatory text — essentially a pointer to a manufacturer document"],"plain_english_summary":"**What this is:** This is an **Airworthiness Directive (AD)** — a mandatory safety order issued by the Civil Aviation Safety Authority (CASA) for specific aircraft.\n\n**What it does:** It requires owners and operators of **Pilatus Britten-Norman BN-2 series aeroplanes** (commonly known as Islander aircraft) to inspect and potentially modify how the **aileron mass balance** is attached to the wing.\n\n**Why this matters:** The aileron mass balance is a weight attached to the aileron (the moving surface on the wing that controls roll). If this attachment fails, it can cause dangerous vibrations or loss of control. This AD mandates checking this critical component to prevent accidents.\n\n**Who must comply:** Anyone operating these aircraft in Australia.\n\n**How to comply:** Follow the instructions in **Britten-Norman Service Bulletin BN-2/SB.67** — a technical document from the manufacturer detailing the inspection and modification steps.\n\n**Key flexibility:** Unlike most maintenance tasks that require a licensed aircraft mechanic, the **daily inspection** portion of this AD can be performed and signed off by the **pilot** themselves."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bn-2-27-aileron-mass-balance-attachment-inspection-and-modification","history":"/api/acts/ad-bn-2-27-aileron-mass-balance-attachment-inspection-and-modification/history","analysis":"/api/acts/ad-bn-2-27-aileron-mass-balance-attachment-inspection-and-modification/analysis","conflicts":"/api/acts/ad-bn-2-27-aileron-mass-balance-attachment-inspection-and-modification/conflicts","importantCases":"/api/acts/ad-bn-2-27-aileron-mass-balance-attachment-inspection-and-modification/important-cases","documents":"/api/acts/ad-bn-2-27-aileron-mass-balance-attachment-inspection-and-modification/documents"}}