{"id":"F2006B02200","name":"AD/AC-SNOW/1 - Mixture Control Lever Quadrant - Modification","slug":"ad-ac-snow-1-mixture-control-lever-quadrant-modification","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41430,"registerId":"commonwealth-F2006B02200-current","compilationNumber":null,"startDate":"2026-04-01","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AC-SNOW/1 - Mixture Control Lever Quadrant - Modification","content":"---\nmeta-content-style-type: text/css\nmeta-content-type: application/xhtml+xml; charset=utf-8\nmeta-description: CASA Airworthiness Directive\nmeta-generator: Aspose.Words for .NET 22.10.0\nmeta-keywords: Issue 8/1966,Aircraft below 5700 kg,Ayres Thrush (Snow) Commander Series Aeroplanes,Mixture Control Lever Quadrant - Modification,1\ntitle: Airworthiness Directive - AD/AC-SNOW/1 - Mixture Control Lever Quadrant - Modification\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)  Ayres Thrush (Snow) Commander Series Aeroplanes\n\n \n\nAD/AC-SNOW/1 Mixture Control Lever Quadrant - Modification 8/66\n\nApplicability: All models.\n\n \n\nRequirement: Mark or remark the mixture control lever quadrant to indicate clearly the following positions:\n\n \n\n1. The minimum lean position - to be designated “LEAN”.\n\n\n \n\n2.    The rearmost position - to be designated “CUT-OFF”.\n\n \n\nThe minimum lean position of the mixture control lever is the rear-most position it can reach without operating the idle cut-off valve.\n\n \n\nCompliance: Forthwith.\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":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1857},"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"The directive maintains its original limited scope—a specific airworthiness modification requiring labeling of mixture controls on the Ayres Thrush (Snow) Commander aircraft series. It has not expanded beyond this single safety purpose."},"complexity_factors":["Single, unambiguous operational requirement (marking two positions)","No defined terms, cross-references, or interpretive provisions","No exceptions, conditions, or nested logic","Extremely brief text with plain language instructions"],"plain_english_summary":"This is an **aviation safety rule** (called an Airworthiness Directive) that applies to all models of the **Ayres Thrush (Snow) Commander** series of agricultural aircraft.\n\n**What it requires:**\nOwners must mark or remark the **mixture control lever** (the cockpit control that adjusts the fuel-to-air ratio going to the engine) with two clear labels:\n*   **\"LEAN\"** — indicating the minimum lean position (the leanest fuel mixture setting before the engine cuts out)\n*   **\"CUT-OFF\"** — indicating the rearmost position (which stops fuel flow and shuts down the engine)\n\n**Why it matters:**\nWithout clear labels, a pilot might accidentally move the lever into the \"cut-off\" position when they only intended to lean the mixture, causing unexpected engine failure during flight.\n\n**Who must comply:**\nAnyone operating these specific aircraft must make this modification **immediately**."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ac-snow-1-mixture-control-lever-quadrant-modification","history":"/api/acts/ad-ac-snow-1-mixture-control-lever-quadrant-modification/history","analysis":"/api/acts/ad-ac-snow-1-mixture-control-lever-quadrant-modification/analysis","conflicts":"/api/acts/ad-ac-snow-1-mixture-control-lever-quadrant-modification/conflicts","importantCases":"/api/acts/ad-ac-snow-1-mixture-control-lever-quadrant-modification/important-cases","documents":"/api/acts/ad-ac-snow-1-mixture-control-lever-quadrant-modification/documents"}}