{"id":"F2006B04736","name":"AD/BN-2/25 Amdt 3 - Wing Mounted Engine Upper Mounting Brackets","slug":"ad-bn-2-25-amdt-3-wing-mounted-engine-upper-mounting-brackets","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44500,"registerId":"commonwealth-F2006B04736-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BN-2/25 Amdt 3 - Wing Mounted Engine Upper Mounting Brackets","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nPilatus Britten-Norman BN-2 Series Aeroplanes\n\nAD/BN-2/25\n\nAmdt 3\n\n  \n\nWing Mounted Engine Upper Mounting Brackets\n\n  \n8/85 DM\n\nApplicability: All Model BN-2 and BN-2T Islander Series.\n\nRequirement: Action in accordance with Pilatus Britten-Norman S.B. BN-2/SB.61 issue 5\\. Compliance: Unless already accomplished, as detailed in the Requirement Document.\n\nBackground: 1. Cracks may develop across the mounting bracket lugs, the main bolt holes and the reinforcing doubler securing rivet locations.\n\n    2. Elongation and wear can occur at the main bolt holes, together with possible lug assembly distortion and fretting between the main bolt hole lug and bush where fitted.\n\n    3. Unacceptable lug edge distances may have resulted from faulty lug doubler plate sub-assembly at manufacture. This Directive is amended to delete all reference to requirements from the title and eliminate any ambiguity relating to requirement actions regarding the intent of this document.","sortOrder":0}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This amendment is purely editorial — it removes requirement references from the title to eliminate ambiguity. The substantive safety scope (inspecting and repairing wing-mounted engine upper mounting brackets) remains unchanged from the original directive issued in 1985 (8/85 DM)."},"complexity_factors":["Short, single-purpose directive (approximately 200 words)","Only 2 defined applicability terms (Model BN-2 and BN-2T Islander Series)","Single cross-reference to external technical document (Service Bulletin BN-2/SB.61 Issue 5)","Simple conditional logic: compliance required 'unless already accomplished'","No nested exceptions or complex procedural branching","Amendment history is straightforward (deleting references from title only)"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires specific maintenance actions on certain aircraft.\n\n**What it does:**\n- Requires owners and operators of **Pilatus Britten-Norman BN-2 and BN-2T Islander aircraft** to inspect and repair the **upper mounting brackets** that attach the engines to the wings.\n\n**Why it matters:**\n- These brackets can develop **dangerous cracks** in the metal lugs and bolt holes, plus wear and distortion where the engine connects to the wing.\n- Some aircraft may have been built with **faulty manufacturing** that left insufficient metal around critical bolt holes (called \"edge distance\"), weakening the structure.\n- If these problems aren't fixed, the engine could detach from the wing in flight.\n\n**What must be done:**\n- Follow the manufacturer's **Service Bulletin BN-2/SB.61 Issue 5** — a technical instruction document that details exactly how to inspect and repair the brackets.\n- This must be done unless it has already been completed.\n\n**Who this affects:**\n- Anyone who owns, operates, or maintains BN-2 or BN-2T Islander aircraft in Australia.\n\n**What's new in this version (Amendment 3):**\n- The title has been cleaned up to remove references to specific requirements, making it clearer that the entire Service Bulletin must be followed."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The amendment removes references to requirements from the title and clarifies intent to eliminate ambiguity (Background para 3). It does not alter the directive’s applicability (All Model BN‑2 and BN‑2T) or the substantive instruction to follow the Pilatus service bulletin (Requirement), so the technical scope remains the same."},"complexity_factors":["Cross‑reference to a manufacturer service bulletin for technical instructions (Requirement: Pilatus Britten‑Norman S.B. BN‑2/SB.61 issue 5).","Technical nature of work (inspection for cracks, elongation, wear, lug distortion, fretting and possible repair/replacement) (Background paragraphs 1–2).","Mandatory compliance language with limited timing detail (‘Unless already accomplished, as detailed in the Requirement Document’) (Compliance).","Applicability to the entire BN‑2/BN‑2T fleet increases operational impact and coordination needs (Applicability: All Model BN‑2 and BN‑2T Islander Series).","Amendment changes wording to remove ambiguity but does not itself specify new technical measures (Background paragraph 3)."],"plain_english_summary":"This Airworthiness Directive requires operators of Pilatus Britten‑Norman BN‑2 and BN‑2T Islanders to carry out the inspections and corrective work set out in Pilatus Britten‑Norman Service Bulletin BN‑2/SB.61 issue 5 for the wing‑mounted engine upper mounting brackets. It responds to reported cracking, wear, lug distortion and possible faulty doubler plate assembly and makes compliance mandatory while clarifying the directive’s wording to remove ambiguity."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bn-2-25-amdt-3-wing-mounted-engine-upper-mounting-brackets","history":"/api/acts/ad-bn-2-25-amdt-3-wing-mounted-engine-upper-mounting-brackets/history","analysis":"/api/acts/ad-bn-2-25-amdt-3-wing-mounted-engine-upper-mounting-brackets/analysis","conflicts":"/api/acts/ad-bn-2-25-amdt-3-wing-mounted-engine-upper-mounting-brackets/conflicts","importantCases":"/api/acts/ad-bn-2-25-amdt-3-wing-mounted-engine-upper-mounting-brackets/important-cases","documents":"/api/acts/ad-bn-2-25-amdt-3-wing-mounted-engine-upper-mounting-brackets/documents"}}