{"id":"F2006B04585","name":"AD/BELL 212/53 - Main Rotor Yoke","slug":"ad-bell-212-53-main-rotor-yoke","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"repealed","isInForce":false,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":114321,"registerId":"commonwealth-F2006B04585-current","compilationNumber":null,"startDate":"2026-04-03","status":"Repealed","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 212/53 - Main Rotor Yoke","content":"COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n![](image.001.png)  \nBell Helicopter Textron 212 Series Helicopters\n\nAD/BELL 212/53 Main Rotor Yoke 2/95\n\nApplicability: All Bell 212 model helicopters with Main Rotor Yokes P/N 204-011-102 (all dash numbers) installed.\n\nRequirement: 1. Remove Main Rotor Yoke from the hub assembly. Visually inspect the pillow block bushing holes for corrosion and mechanical damage. Inspect the yoke for cracks in accordance with the BTHI component repair and overhaul manual, using the magnetic particle method.\n\n2. Rework damaged yokes in accordance with the limits of the BTHI component repair and overhaul manual. Remove from service cracked components and components that cannot be reworked within those limits.\n\nNote: FAA AD 93-05-01 refers.\n\nCompliance: 1. Inspect in accordance with Requirement 1 before 1200 hours time in service or within 100 hours time in service after 2 February 1995, whichever occurs later. Re-inspect in accordance with requirement 1 at intervals not to exceed 1200 hours time in service.\n\n2. Rework damaged yokes in accordance with Requirement 2 before further flight.\n\nBackground: There have been 12 cracks reported in the main rotor yoke pillow block bushing holes. This AD is intended to detect corrosion and cracking from corrosion pits in the main rotor yoke assembly which could result in failure of the main rotor system and loss of control of the helicopter.","sortOrder":0}],"analysis":{"kimi_summary":{"_metrics":{"model":"kimi-k2.5","source":"moonshot-batch","completionTokens":1595},"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This appears to reflect the original scope of the directive. It maintains a narrow, targeted focus on main rotor yoke inspections for a specific helicopter model, consistent with the stated background of addressing reported cracks in that component."},"complexity_factors":["Technical aviation terminology requires specialist engineering knowledge (e.g., 'pillow block bushing holes', 'magnetic particle method')","External reference dependency — requirements are defined by reference to the BTHI component repair manual rather than being fully specified in the instrument","Dual-track compliance calculation requiring operators to determine 'whichever occurs later' between hour-based and date-based triggers"],"plain_english_summary":"This rule requires operators of Bell 212 helicopters to perform recurring mandatory inspections of main rotor yokes (part 204-011-102) for corrosion and cracking using magnetic particle inspection, focusing on the pillow block bushing holes. Initial inspection is due by 1,200 flight hours or within 100 hours after 2 Feb 1995, then every 1,200 hours; damaged or cracked yokes must be repaired within limits or replaced before flight.\n\nIt matters because twelve cracks were found and yoke failure could cause catastrophic loss of the main rotor and loss of control."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-212-53-main-rotor-yoke","history":"/api/acts/ad-bell-212-53-main-rotor-yoke/history","analysis":"/api/acts/ad-bell-212-53-main-rotor-yoke/analysis","conflicts":"/api/acts/ad-bell-212-53-main-rotor-yoke/conflicts","importantCases":"/api/acts/ad-bell-212-53-main-rotor-yoke/important-cases","documents":"/api/acts/ad-bell-212-53-main-rotor-yoke/documents"}}