{"id":"F2006B02099","name":"AD/AC/40 - Engine Mount Yoke - Inspection","slug":"ad-ac-40-engine-mount-yoke-inspection","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":41329,"registerId":"commonwealth-F2006B02099-current","compilationNumber":null,"startDate":"2026-04-01","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/AC/40 - Engine Mount Yoke - Inspection","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 4/1969,Aircraft below 5700 kg,Twin Commander (Gulfstream/Rockwell/ Aerocommander 500, 600 and 700) Series Aeroplanes,Engine Mount Yoke - Inspection,40\ntitle: Airworthiness Directive - AD/AC/40 - Engine Mount Yoke - Inspection\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/40 Engine Mount Yoke - Inspection 4/69\n\nApplicability: All 680T, 680V and 680W series, S/Nos. 1473 to 1850 with more than 500 hours total time in service.\n\n \n\nDocument: Aero Commander SB No. 94.\n\n \n\nCompliance: Within 100 hours’ time in service after 15 April 1969 and thereafter at intervals not exceeding 100 hours’ time in service.\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":2102},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This directive remains tightly focused on its original safety purpose: inspecting engine mount yokes on the specified Twin Commander 680 series aircraft. There is no evidence of scope expansion into unrelated airframe components, different aircraft models, or additional operational requirements beyond the original inspection mandate."},"complexity_factors":["Single operative provision with no subsections or Parts","Limited applicability criteria requiring conjunction of three conditions (model series, serial number range, and minimum flight hours)","No defined terms or interpretation section","Single external reference to manufacturer Service Bulletin No. 94","Straightforward compliance timeline without exceptions or alternative compliance methods"],"plain_english_summary":"**What this does:** This directive mandates repetitive safety inspections of engine mount yokes (the structural brackets connecting the engine to the aircraft frame) on specific Twin Commander aircraft models.\n\n**Who it affects:** Owners and operators of **680T, 680V, and 680W series** Twin Commander aircraft with **serial numbers 1473 through 1850**, but **only if** the aircraft has logged more than 500 total flight hours.\n\n**What must be done:**\n*   **First inspection:** Complete within 100 flight hours after 15 April 1969\n*   **Repeat inspections:** Conduct every 100 flight hours thereafter (ongoing requirement)\n*   **Standard:** Follow the procedures outlined in **Aero Commander Service Bulletin No. 94**\n\n**Why it matters:** Engine mount yokes bear extreme structural loads. Fatigue or cracks in these components can lead to engine separation during flight. This rule prevents catastrophic failures by catching defects before they progress."}},"importantCases":[],"_links":{"self":"/api/acts/ad-ac-40-engine-mount-yoke-inspection","history":"/api/acts/ad-ac-40-engine-mount-yoke-inspection/history","analysis":"/api/acts/ad-ac-40-engine-mount-yoke-inspection/analysis","conflicts":"/api/acts/ad-ac-40-engine-mount-yoke-inspection/conflicts","importantCases":"/api/acts/ad-ac-40-engine-mount-yoke-inspection/important-cases","documents":"/api/acts/ad-ac-40-engine-mount-yoke-inspection/documents"}}