{"id":"F2006B02109","name":"AD/AC/5 - Landing Gear Selector Valve - Removal of AN 6207 Check Valve","slug":"ad-ac-5-landing-gear-selector-valve-removal-of-an-6207-check-valve","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41339,"registerId":"commonwealth-F2006B02109-current","compilationNumber":null,"startDate":"2026-04-01","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AC/5 - Landing Gear Selector Valve - Removal of AN 6207 Check Valve","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 NK,Aircraft below 5700 kg,Twin Commander (Gulfstream/Rockwell/ Aerocommander 500, 600 and 700) Series Aeroplanes,Landing Gear Selector Valve - Removal of AN 6207 Check Valve,5\ntitle: Airworthiness Directive - AD/AC/5 - Landing Gear Selector Valve - Removal of AN 6207 Check Valve\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)  Twin Commander (Gulfstream/Rockwell/ Aerocommander 500, 600 and 700) Series Aeroplanes\n\n \n\nAD/AC/5 Landing Gear Selector Valve - Removal NK\n\nof AN 6207 Check Valve\n\nApplicability: All models: S/Nos. 1 to 580. Document: Aero Commander SB No. 44. Compliance:  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\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":2174},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"The directive maintains its original narrow scope targeting the specific landing gear valve modification for early serial number Twin Commander aircraft. No evidence of scope expansion beyond the original safety intent."},"complexity_factors":["Single, unambiguous compliance action (removal of one specified component)","Reference to external technical document (Service Bulletin No. 44) required for full instructions","No conditional logic, exceptions, or alternative compliance methods specified","Narrow applicability limited to specific aircraft models and serial number range","No defined terms or interpretation sections"],"plain_english_summary":"**What this means:**\n\nThis is a mandatory safety order requiring the immediate removal of a specific component—the AN 6207 check valve—from the landing gear selector valve on certain Twin Commander aircraft.\n\n**Who is affected:**\n- Owners and operators of Twin Commander (also marketed as Gulfstream/Rockwell/Aero Commander) 500, 600, and 700 series aeroplanes\n- Only applies to aircraft with serial numbers 1 through 580\n\n**What you must do:**\n- Remove the AN 6207 check valve from the landing gear selector valve system immediately (\"forthwith\" means without delay)\n- Follow the technical instructions in **Aero Commander Service Bulletin No. 44** (an external maintenance document)\n\n**Why this matters:**\nThis directive addresses a specific safety defect with the check valve that could compromise the landing gear system. Until this action is completed, the aircraft is considered unairworthy and cannot legally fly. Compliance is mandatory under Part 39 of the Civil Aviation Regulations."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ac-5-landing-gear-selector-valve-removal-of-an-6207-check-valve","history":"/api/acts/ad-ac-5-landing-gear-selector-valve-removal-of-an-6207-check-valve/history","analysis":"/api/acts/ad-ac-5-landing-gear-selector-valve-removal-of-an-6207-check-valve/analysis","conflicts":"/api/acts/ad-ac-5-landing-gear-selector-valve-removal-of-an-6207-check-valve/conflicts","importantCases":"/api/acts/ad-ac-5-landing-gear-selector-valve-removal-of-an-6207-check-valve/important-cases","documents":"/api/acts/ad-ac-5-landing-gear-selector-valve-removal-of-an-6207-check-valve/documents"}}