{"id":"F2006B09126","name":"AD/DHC-6/38 - Horizontal Stabiliser Rear Spar - Inspection","slug":"ad-dhc-6-38-horizontal-stabiliser-rear-spar-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115679,"registerId":"commonwealth-F2006B09126-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-6/38 - Horizontal Stabiliser Rear Spar - 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)  DHC-6 (Twin Otter) Series Aeroplanes\n\n \n\nAD/DHC-6/38 Horizontal Stabiliser Rear Spar - Inspection 7/74\n\nApplicability: All models with S/Nos. 1 to 393 excluding 107, 168, 182, 184, 209, 383, 385, 386,\n\n390 and 391.\n\n \n\nDocument: De Havilland of Canada SB No. 6/310.\n\n \n\nCompliance: Within 100 hours time in service after 31 August 1974.\n\n \n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":2,"scope_assessment":{"changed":false,"description":"The instrument sets a defined, serial-number–limited scope and a single compliance deadline; the text contains no indication that the scope has been amended from an earlier version or that its applicability was changed. (Applicability; Compliance.)"},"complexity_factors":["Single required action (inspection) rather than ongoing monitoring or multiple obligations","Clear, short compliance window (within 100 hours TIS after a fixed date)","Narrow, serial-number–based applicability with a short exclusions list","Procedural detail delegated to an external service bulletin (SB No. 6/310)","No layered conditions, exceptions, or follow-up reporting requirements in the text supplied"],"plain_english_summary":"This directive mandates inspection of the horizontal stabiliser rear spar on De Havilland DHC-6 (Twin Otter) aeroplanes with serial numbers 1–393, excluding S/Ns 107, 168, 182, 184, 209, 383, 385, 386, 390 and 391. Procedures are those in De Havilland Service Bulletin No. 6/310, and the inspection must be completed within 100 hours time-in-service after 31 August 1974.\n\nOwners/operators (and their maintenance providers) must arrange and pay for the inspection, which affects maintenance scheduling and aircraft availability."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a discrete, single-issue Airworthiness Directive from 1974 addressing a specific structural inspection requirement. It has not expanded beyond its original purpose of ensuring the airworthiness of DHC-6 Twin Otter horizontal stabiliser rear spars."},"complexity_factors":["Single, specific maintenance task with clear applicability criteria","Only one cross-reference (to De Havilland Service Bulletin 6/310)","Simple compliance deadline (100 hours time in service after fixed date)","Straightforward serial number-based applicability with explicit exclusions","No nested conditions, exceptions to exceptions, or defined terms section","Extremely short document (approximately 100 words of substantive content)"],"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 action on certain aircraft.\n\n**What it does:**\nOrders owners and operators of specific De Havilland DHC-6 Twin Otter aircraft to inspect the **horizontal stabiliser rear spar** — a critical structural component at the back of the plane that helps keep the aircraft stable in flight.\n\n**Who it affects:**\nAll DHC-6 Twin Otter aircraft with **serial numbers 1 through 393**, **except** for eleven specific serial numbers (107, 168, 182, 184, 209, 383, 385, 386, 390, and 391).\n\n**What must be done:**\nOperators must follow the inspection procedure detailed in **De Havilland Service Bulletin No. 6/310** and complete the work **within 100 hours of flight time after 31 August 1974**.\n\n**Why it matters:**\nAirworthiness Directives are legally binding safety instructions. Failure to comply means the aircraft cannot legally fly in Australian airspace. This particular directive addresses potential structural defects in the tail section that could affect flight safety."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-6-38-horizontal-stabiliser-rear-spar-inspection","history":"/api/acts/ad-dhc-6-38-horizontal-stabiliser-rear-spar-inspection/history","analysis":"/api/acts/ad-dhc-6-38-horizontal-stabiliser-rear-spar-inspection/analysis","conflicts":"/api/acts/ad-dhc-6-38-horizontal-stabiliser-rear-spar-inspection/conflicts","importantCases":"/api/acts/ad-dhc-6-38-horizontal-stabiliser-rear-spar-inspection/important-cases","documents":"/api/acts/ad-dhc-6-38-horizontal-stabiliser-rear-spar-inspection/documents"}}