{"id":"F2006B09029","name":"AD/DHC-2/12 Amdt 2 - Left and Right Wing Intermediate Rib Assembly Stations 15.50, 29.00 and 42.50 - Inspection and Modification","slug":"ad-dhc-2-12-amdt-2-left-and-right-wing-intermediate-rib-assembly-stations-15-50-29-00-and-42-50-insp","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":52718,"registerId":"commonwealth-F2006B09029-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-2/12 Amdt 2 - Left and Right Wing Intermediate Rib Assembly Stations 15.50, 29.00 and 42.50 - 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)  DHC-2 (Beaver) Series Aeroplanes\n\n \n\nAD/DHC-2/12\n\nAmdt 2\n\n\nLeft and Right Wing Intermediate Rib Assembly Stations 15.50, 29.00 and 42.50 - Inspection and Modification\n\n\n10/84\n\n \n\nApplicability: All model DHC-2 aircraft.\n\n \n\nRequirement: De Havilland of Canada EB Series “B” No. 35.\n\n \n\nCompliance: Unless already accomplished inspect within 250 hours time in service after 17 September 1984 and thereafter at intervals not exceeding 500 hours time in service until modification 2/1497 is incorporated.\n\n \n\nBackground:  This Directive is amended to correct a rib station number, include an additional rib assembly and clarify inspection and modification requirements.\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":{"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This amendment remains tightly focused on its original purpose: ensuring structural integrity of DHC-2 wing ribs. The changes are minor corrections (fixing a station number, adding one rib assembly, clarifying language) rather than expansion into new operational areas."},"complexity_factors":["Very short document (under 300 words)","Only 4 defined elements: aircraft model, specific rib stations (15.50, 29.00, 42.50), reference to external engineering bulletin (EB Series 'B' No. 35), and modification kit number (2/1497)","Single compliance pathway with clear timeframes (250 hours initial, 500 hours recurring)","No nested exceptions or conditional logic — straightforward 'inspect until modified' requirement","No cross-references to other legislation beyond the parent Civil Aviation Regulations 1998"],"plain_english_summary":"This is an **Airworthiness Directive** — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) for aircraft.\n\n**What it does:**\nOrders owners and operators of **De Havilland DHC-2 \"Beaver\" aircraft** to inspect specific parts of the left and right wings (called \"intermediate rib assemblies\" at three specific locations along the wing). If problems are found, they must carry out a specific modification to fix the issue.\n\n**Who it affects:**\nAnyone who owns or operates a DHC-2 Beaver aircraft in Australia.\n\n**What must be done:**\n- **First inspection:** Within 250 hours of flying time after 17 September 1984\n- **Repeat inspections:** Every 500 hours of flying time after that\n- **Permanent fix:** Install modification kit number 2/1497 (this stops the need for repeat inspections)\n\n**Why it matters:**\nWing rib assemblies are structural parts that help keep the wing strong. This directive prevents potential wing failures that could cause crashes. The directive was updated (Amendment 2) to fix a mistake in a part number, add another rib location that needs checking, and make the instructions clearer."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":true,"description":"The amendment changes the Directive by correcting a rib station number, adding an additional rib assembly to the inspection requirement, and clarifying inspection and modification requirements (Background). Applicability remains ‘all model DHC‑2 aircraft’ (Applicability), but the set of structural locations subject to inspection and the procedural clarity have been expanded/altered compared with the earlier text."},"complexity_factors":["Narrow technical focus on specific wing rib assembly station numbers (requires aircraft structural knowledge).","Time‑based compliance schedule with an initial deadline and recurring intervals tied to hours in service (dates and hours tracking required) (Compliance).","Cross‑reference to an external manufacturer document for procedures (De Havilland EB Series “B” No. 35) rather than including procedural detail in the Directive (Requirement).","Linkage between continuing inspection duty and incorporation of a named modification (modification 2/1497) — compliance ends only upon installation of that modification (Compliance).","Amendment corrects and expands prior text (corrected station number and an additional rib assembly), so implementers must reconcile this version with prior maintenance records (Background)."],"plain_english_summary":"This amendment to AD/DHC‑2/12 requires owners/operators of De Havilland DHC‑2 (Beaver) aeroplanes to inspect specified left and right wing intermediate rib assemblies per De Havilland EB Series “B” No. 35. If not already done, inspections are due within 250 hours TIS after 17 Sept 1984 and then every 500 hours until modification 2/1497 is fitted. The change corrects a rib station number, adds an assembly, clarifies requirements, and imposes inspection or modification costs on operators."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-2-12-amdt-2-left-and-right-wing-intermediate-rib-assembly-stations-15-50-29-00-and-42-50-insp","history":"/api/acts/ad-dhc-2-12-amdt-2-left-and-right-wing-intermediate-rib-assembly-stations-15-50-29-00-and-42-50-insp/history","analysis":"/api/acts/ad-dhc-2-12-amdt-2-left-and-right-wing-intermediate-rib-assembly-stations-15-50-29-00-and-42-50-insp/analysis","conflicts":"/api/acts/ad-dhc-2-12-amdt-2-left-and-right-wing-intermediate-rib-assembly-stations-15-50-29-00-and-42-50-insp/conflicts","importantCases":"/api/acts/ad-dhc-2-12-amdt-2-left-and-right-wing-intermediate-rib-assembly-stations-15-50-29-00-and-42-50-insp/important-cases","documents":"/api/acts/ad-dhc-2-12-amdt-2-left-and-right-wing-intermediate-rib-assembly-stations-15-50-29-00-and-42-50-insp/documents"}}