{"id":"F2008L02799","name":"AD/AC-SNOW/1 - Mixture Control Lever Quadrant - Modification - CANCELLED","slug":"ad-ac-snow-1-mixture-control-lever-quadrant-modification-cancelled","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":74950,"registerId":"commonwealth-F2008L02799-current","compilationNumber":null,"startDate":"2026-04-02","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Ayres Thrush (Snow) Commander Series Aer","sectionType":"division","heading":"Ayres Thrush (Snow) Commander Series Aeroplanes","content":"### Ayres Thrush (Snow) Commander Series Aeroplanes\n\n| AD/AC-SNOW/1 | Mixture Control Lever Quadrant - Modification | 9/2008 |\n| ------------ | --------------------------------------------- | ------ |\n\n| Requirement: | CANCELLED.                                                                                                                                                                                                                                                                                                 |\n| ------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n|              | This AD is cancelled on 28 August 2008.                                                                                                                                                                                                                                                                    |\n| Background:  | This unique Australian AD, raised in 1966, required a modification to mark or re-mark the mixture control lever quadrant to indicate the \"LEAN\" and \"CUT-OFF\" positions.Compliance was forthwith.As all affected aircraft would have been modified by now, this AD is considered to be no longer required. |\n\n![](image.001.png)\n\nJames Coyne  \nDelegate of the Civil Aviation Safety Authority\n\n17 July 2008","sortOrder":0},{"sectionNumber":"AD/AC-SNOW/1","sectionType":"part","heading":"AD/AC-SNOW/1","content":"## AD/AC-SNOW/1","sortOrder":1},{"sectionNumber":"Mixture Control Lever Quadrant - Modific","sectionType":"part","heading":"Mixture Control Lever Quadrant - Modification","content":"## Mixture Control Lever Quadrant - Modification","sortOrder":2},{"sectionNumber":"9/2008","sectionType":"part","heading":"9/2008","content":"## 9/2008","sortOrder":3}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1760},"content_quality":"ok","complexity_score":1,"scope_assessment":{"changed":false,"description":"This instrument terminates the existing airworthiness directive entirely rather than expanding its application. The scope has not grown beyond the original purpose; instead, the active requirement has been removed due to universal compliance and obsolescence."},"complexity_factors":["Single operative provision consisting of one word: 'CANCELLED'","No defined terms, interpretation section, or legal cross-references","No conditional logic, exceptions, or compliance deadlines","Historical background provided for context only and imposes no legal obligations"],"plain_english_summary":"**What this does**\nThis document scraps a 42-year-old aircraft safety rule that required owners of specific crop-dusting planes (Ayres Thrush and Snow Commander series) to mark their fuel mixture control levers with \"LEAN\" and \"CUT-OFF\" positions.\n\n**Who it affects**\nOwners and operators of Ayres Thrush and Snow Commander aircraft. However, there is **no action required**—this directive simply removes an old rule that everyone has already complied with.\n\n**Why it matters**\nThe original rule from 1966 was designed to prevent engine problems by ensuring pilots could clearly see the fuel mixture settings. Because all affected aircraft have been modified over the past four decades, the Civil Aviation Safety Authority has cancelled the directive as it is now redundant. This is housekeeping to clear obsolete rules from the books."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ac-snow-1-mixture-control-lever-quadrant-modification-cancelled","history":"/api/acts/ad-ac-snow-1-mixture-control-lever-quadrant-modification-cancelled/history","analysis":"/api/acts/ad-ac-snow-1-mixture-control-lever-quadrant-modification-cancelled/analysis","conflicts":"/api/acts/ad-ac-snow-1-mixture-control-lever-quadrant-modification-cancelled/conflicts","importantCases":"/api/acts/ad-ac-snow-1-mixture-control-lever-quadrant-modification-cancelled/important-cases","documents":"/api/acts/ad-ac-snow-1-mixture-control-lever-quadrant-modification-cancelled/documents"}}