{"id":"F2006B04748","name":"AD/BN-2/36 - Engine Mounting Brackets - Inspection","slug":"ad-bn-2-36-engine-mounting-brackets-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44512,"registerId":"commonwealth-F2006B04748-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BN-2/36 - Engine Mounting Brackets - 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-2/36 Engine Mounting Brackets - Inspection NK\n\nApplicability: All models BN-2A which have achieved 2 years since date of manufacture. Document:               Britten Norman SB No. BN-2/SB.91.\n\nCompliance: Within 100 hours time in service after 15 July 1976.\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":3,"scope_assessment":{"changed":false,"description":"The directive's scope is limited and specific in the text provided: it applies to BN-2A airframes that are at least two years old and requires a single inspection per the referenced Service Bulletin within the stated 100-hour window (Applicability; Document; Compliance). No alteration of that scope is indicated in the instrument text supplied."},"complexity_factors":["Narrow applicability: only \"All models BN-2A which have achieved 2 years since date of manufacture\" (Applicability).","Single, time-limited action: one inspection required within a fixed 100-hour window after 15 July 1976 (Compliance).","Dependence on external technical document: the directive refers to Britten Norman SB No. BN-2/SB.91 for the inspection procedure and criteria (Document), so technical detail is not in the directive itself.","Limited procedural detail: directive sets duty and deadline but does not specify enforcement, acceptable repairs, or follow-up intervals, creating some interpretive burden for operators and maintainers.","Clear deadlines reduce administrative ambiguity but require coordination with maintenance schedules, creating practical scheduling complexity for operators."],"plain_english_summary":"What this instrument does (mechanically)\n\n- Requires operators of certain Pilatus Britten-Norman BN-2 aeroplanes to have the engine mounting brackets inspected. The directive applies to \"All models BN-2A which have achieved 2 years since date of manufacture\" (Applicability). The inspection is to be performed in accordance with Britten Norman Service Bulletin No. BN-2/SB.91 (Document). Compliance must occur \"within 100 hours time in service after 15 July 1976\" (Compliance).\n\nStated purpose and how that maps to effects\n\n- The title and the referenced service bulletin identify the action as an inspection of engine mounting brackets. That indicates the directive’s operative purpose is to verify the condition of those fittings before further flight operations. This is a statement of the instrument’s intended action (from the title and Document), not an assertion about wider policy aims.\n\nWho decides and who pays\n\n- Decision: The operator/owner of each affected BN-2A decides when and how to schedule the inspection, subject to the timing requirement (Applicability; Compliance). The directive delegates the technical inspection procedure to the referenced service bulletin (Document).\n- Cost bearer: The operator/owner will bear direct costs of performing the inspection and any remedial repairs required by the inspection. Those costs and downtime are implied by the need to carry out the inspection within the stated timeframe and to follow the Service Bulletin (Applicability; Document; Compliance).\n\nBehavioural effects, incentives and trade-offs\n\n- Required behaviour: Operators of BN-2A airframes older than two years must arrange the inspection within the specified 100 hours time-in-service after 15 July 1976 (Applicability; Compliance).\n- Scheduling and downtime: The requirement creates a short-term scheduling obligation (operator must fit the inspection into maintenance cycles within the 100-hour window). If defects are found, operators may face additional repair time and cost, and possible further grounding until repairs are completed (Document; Compliance).\n- Substitution effects: Operators may choose to advance other maintenance to coincide with the inspection to reduce total downtime, or defer some non-mandatory tasks, but the directive itself mandates only the inspection in the timeframe given (Applicability; Document; Compliance).\n\nCompliance burden and implementation risk\n\n- Compliance burden: The directive imposes a one-off inspection requirement for the defined fleet subset. The technical steps are not reproduced in the directive; operators must follow the referenced Service Bulletin for procedure and criteria (Document). That reliance on an external technical document means the directive does not itself specify inspection detail.\n- Implementation risk: The directive does not specify enforcement measures, acceptable repair actions, or follow-up intervals. Where the Service Bulletin lacks clarity or where defects require judgement, operators and maintenance organisations will need to interpret the SB or seek technical direction. The directive sets the deadline but refers operators to the SB for the substantive work (Document; Compliance).\n\nConcentrated benefits, diffuse costs, and discretion\n\n- Concentrated benefits: Any direct benefit (reduced risk of bracket failure on affected BN-2A aircraft) accrues to operators, passengers and third parties directly exposed to those specific aircraft. This follows from the targeted Applicability.\n- Diffuse costs: Costs (inspection labour, parts, downtime) are borne by the relatively small population of affected BN-2A operators. The directive does not create a recurring network-wide cost—its obligation is framed as a time-limited inspection (Applicability; Compliance).\n- Bureaucratic discretion: The directive identifies the required action and the technical reference; it does not, in the text provided, create ongoing administrative discretion or a continuing inspection regime beyond the specified compliance action (Applicability; Document; Compliance).\n\nNet practical effect (summary)\n\n- Operators of BN-2A aircraft more than two years old must, within the 100-hour time-in-service window after 15 July 1976, perform the engine mounting bracket inspection called up by Britten Norman SB No. BN-2/SB.91. The operator bears the inspection cost and any repair costs; the directive relies on the Service Bulletin for technical detail and sets a clear compliance deadline (Applicability; Document; Compliance)."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive focused specifically on engine mounting bracket inspections for one aircraft series. It has not expanded beyond its original purpose; it remains a narrow technical maintenance requirement issued in 1976 with no subsequent amendments visible in this version."},"complexity_factors":["Extremely short document — only 4 substantive lines of regulatory text","Zero defined terms in the directive itself (relies on external document SB.91 for technical details)","No cross-references to other legislation beyond the enabling regulation (CAR 1998 Part 39)","Simple conditional logic: single applicability criterion (2 years since manufacture) + single compliance deadline","No exceptions, exemptions, or nested conditions","Clear, unambiguous command structure: 'Applicability', 'Document', 'Compliance'"],"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 Islander aircraft** to inspect the **engine mounting brackets** — the metal structures that attach the engines to the aircraft's wings or fuselage.\n\n**Who it affects:**\n- **All BN-2A model aircraft** that are **2 years or older** (measured from their manufacture date)\n- Aircraft owners, operators, and maintenance organisations responsible for these planes\n\n**What must be done:**\n- **Inspection required:** A visual or detailed examination of the engine mounting brackets\n- **When:** Within **100 hours of flying time** after **15 July 1976**\n- **How:** Follow the procedures in **Britten-Norman Service Bulletin BN-2/SB.91** (the manufacturer's official maintenance instruction)\n\n**Why it matters:** Engine mounting brackets are critical safety components. If they crack or fail, engines could detach from the aircraft in flight. This AD was issued to catch potential structural problems before they cause catastrophic failure.\n\n**Key point:** This is a **time-limited, one-off inspection** — not a recurring requirement unless further problems are found."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bn-2-36-engine-mounting-brackets-inspection","history":"/api/acts/ad-bn-2-36-engine-mounting-brackets-inspection/history","analysis":"/api/acts/ad-bn-2-36-engine-mounting-brackets-inspection/analysis","conflicts":"/api/acts/ad-bn-2-36-engine-mounting-brackets-inspection/conflicts","importantCases":"/api/acts/ad-bn-2-36-engine-mounting-brackets-inspection/important-cases","documents":"/api/acts/ad-bn-2-36-engine-mounting-brackets-inspection/documents"}}