{"id":"F2006B09104","name":"AD/DHC-6/17 Amdt 1 - Control Column - Lower Sub-Assembly - Inspection","slug":"ad-dhc-6-17-amdt-1-control-column-lower-sub-assembly-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":115657,"registerId":"commonwealth-F2006B09104-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/DHC-6/17 Amdt 1 - Control Column - Lower Sub-Assembly - 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-6/17\n\nAmdt 1\n\nApplicability: All models.\n\n\nControl Column - Lower Sub-Assembly - Inspection\n\n\n8/69\n\n \n\nDocument: De Havilland of Canada SB No. 6/180 Rev. A. Compliance:  As detailed in the requirement document.\n","sortOrder":0}],"analysis":{"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The text provided sets applicability as \"All models\" and requires inspection per the referenced Service Bulletin. Although the instrument is identified as an amendment (\"Amdt 1\"), the supplied text does not state any change to the applicability or the substantive scope within this excerpt. The AD as shown therefore does not, by itself, indicate a changed scope from the original beyond identifying the requirement and pointing to SB No. 6/180 Rev. A for compliance details."},"complexity_factors":["Concise, single-issue directive (control column lower sub-assembly inspection) limits substantive complexity.","Mandates compliance by reference to an external technical document (De Havilland SB No. 6/180 Rev. A), requiring implementers to obtain and read that document to know exact tasks and intervals.","Broad applicability (\"All models\") increases operational scope despite the directive's brevity.","Labelled as an amendment (\"Amdt 1\"), which requires cross-referencing any prior AD to understand the amendment history.","The AD text itself omits enforcement detail and specific procedural steps, shifting complexity to the service bulletin and to operator maintenance processes."],"plain_english_summary":"This CASA Airworthiness Directive (AD/DHC-6/17 Amdt 1) requires operators of all De Havilland DHC‑6 (Twin Otter) models to inspect the control‑column lower sub‑assembly. Compliance must follow the procedures and corrective actions set out in De Havilland of Canada Service Bulletin No. 6/180 Rev. A. The AD makes that inspection a regulatory obligation for operators/maintainers, ensuring continued airworthiness while delegating technical detail to the referenced service bulletin."},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This is a standard, narrow airworthiness directive focused on a specific aircraft type and component. It has not expanded beyond its original safety purpose."},"complexity_factors":["Very short document (approximately 150 words)","Only 1 defined applicability (all DHC-6 models)","Single compliance requirement referencing an external technical document","No nested conditions, exceptions, or cross-references to other legislation","Straightforward command structure: identify aircraft → inspect component → follow manufacturer bulletin"],"plain_english_summary":"This is an **Airworthiness Directive** (AD) — a mandatory safety order issued by Australia's Civil Aviation Safety Authority (CASA) that requires owners and operators of specific aircraft to take action.\n\n**What it does:**\n- Requires inspection of the **control column lower sub-assembly** on **DHC-6 Twin Otter aircraft** (all models).\n- This is a safety-critical component — it's part of the mechanism pilots use to steer the aircraft.\n\n**Who it affects:**\n- Anyone who owns, operates, or maintains DHC-6 (Twin Otter) series aeroplanes in Australia.\n\n**Why it matters:**\n- The directive addresses potential safety defects in the control column assembly that could affect flight control. Failure to comply means the aircraft cannot legally fly.\n\n**What must be done:**\n- Follow the inspection procedures detailed in **De Havilland of Canada Service Bulletin No. 6/180 Revision A**.\n- The directive references this manufacturer document rather than spelling out the steps itself — operators must obtain and follow that bulletin."}},"importantCases":[],"_links":{"self":"/api/acts/ad-dhc-6-17-amdt-1-control-column-lower-sub-assembly-inspection","history":"/api/acts/ad-dhc-6-17-amdt-1-control-column-lower-sub-assembly-inspection/history","analysis":"/api/acts/ad-dhc-6-17-amdt-1-control-column-lower-sub-assembly-inspection/analysis","conflicts":"/api/acts/ad-dhc-6-17-amdt-1-control-column-lower-sub-assembly-inspection/conflicts","importantCases":"/api/acts/ad-dhc-6-17-amdt-1-control-column-lower-sub-assembly-inspection/important-cases","documents":"/api/acts/ad-dhc-6-17-amdt-1-control-column-lower-sub-assembly-inspection/documents"}}