{"id":"F2006B09043","name":"AD/DHC-2/25 - Horizontal Stabiliser Attachment Brackets","slug":"ad-dhc-2-25-horizontal-stabiliser-attachment-brackets","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52755,"registerId":"commonwealth-F2006B09043-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-2/25 - Horizontal Stabiliser Attachment Brackets","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)  DHC-2 (Beaver) Series Aeroplanes\n\n \n\nAD/DHC-2/25 Horizontal Stabiliser Attachment Brackets 11/87\n\nApplicability: All models S/Nos 1 to 1056 Pre-mod 2/1338 and Pre-mod 2/984 (Agricultural). Requirement:               Action in accordance with De Havilland of Canada SB 2/42.\n\nCompliance: Unless already accomplished within the previous 800 hours time in service, within 200 hours time in service after 31 October 1987, thereafter, every 1000 hours time in service.\n\n \n\nBackground: The original issue of this Service Bulletin was a Country of Origin Airworthiness Directive and as such was an initial Australian CofA requirement. However the manufacturer has expanded the applicability and introduced a repeat inspection requirement which necessitates the issue of this Directive.\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":true,"description":"Yes. Background states the manufacturer expanded the Service Bulletin’s applicability and added a repeat inspection requirement; this Directive reflects that expansion and adds a recurring inspection schedule where previously the SB had been an initial Country of Origin CofA requirement (Background)."},"complexity_factors":["Relies on an external technical document (De Havilland SB 2/42) for required work rather than spelling out tasks in the Directive (Requirement).","Applicability is constrained by serial number range and pre‑mod status, requiring record checks (Applicability).","Compliance timing uses three time‑in‑service thresholds (lookback 800 hrs, initial 200 hrs deadline, repeat every 1,000 hrs), creating scheduling and recordkeeping obligations (Compliance).","Introduces a recurring inspection regime (manufacturer added repeat inspections), increasing ongoing maintenance burden (Background).","Historical regulatory change: original Service Bulletin was a Country of Origin CofA requirement; the Directive follows the manufacturer’s expanded applicability (Background)."],"plain_english_summary":"This Airworthiness Directive obliges owners/operators of De Havilland DHC‑2 (Beaver) aircraft (S/Ns 1–1056 and specified pre‑mod agricultural variants) to carry out the work set out in De Havilland of Canada Service Bulletin 2/42 on horizontal stabiliser attachment brackets. Unless that work was done within the previous 800 hours TIS, it must be done within 200 hours after 31 October 1987 and then repeated every 1,000 hours. Operators must arrange and pay for inspections/repairs under the manufacturer’s bulletin; CASA enforces compliance."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific structural fatigue issue on a single aircraft type. The 'expanded applicability' mentioned in the background refers only to the manufacturer's original Service Bulletin broadening from initial certification requirement to ongoing operational requirement, not a legislative scope creep."},"complexity_factors":["Single, specific mechanical component addressed","Only two applicability criteria (serial number range and modification status)","Straightforward compliance timeline (one-time + recurring interval)","No defined terms section — uses plain aviation terminology","No cross-references to other legislation or regulations beyond the parent Civil Aviation Regulations 1998","Single action required (follow manufacturer's Service Bulletin 2/42)"],"plain_english_summary":"This AD mandates inspections of the horizontal stabiliser attachment brackets on De Havilland DHC‑2 “Beaver” aircraft (s/n 1–1056) that lack certain factory mods. Owners must follow Service Bulletin 2/42, carry out any overdue inspection (if not done in the last 800 flight hours, inspect within 200 hours of 31 Oct 1987) and then repeat inspections every 1,000 flight hours.\n\nIt matters because discovered bracket defects could lead to tail loss and loss of control; the checks are legally required in Australia."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-2-25-horizontal-stabiliser-attachment-brackets","history":"/api/acts/ad-dhc-2-25-horizontal-stabiliser-attachment-brackets/history","analysis":"/api/acts/ad-dhc-2-25-horizontal-stabiliser-attachment-brackets/analysis","conflicts":"/api/acts/ad-dhc-2-25-horizontal-stabiliser-attachment-brackets/conflicts","importantCases":"/api/acts/ad-dhc-2-25-horizontal-stabiliser-attachment-brackets/important-cases","documents":"/api/acts/ad-dhc-2-25-horizontal-stabiliser-attachment-brackets/documents"}}