{"id":"F2006B04671","name":"AD/BELL 412/37 - Internal Hoist","slug":"ad-bell-412-37-internal-hoist","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44423,"registerId":"commonwealth-F2006B04671-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 412/37 - Internal Hoist","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 412 Series Helicopters\n\nAD/BELL 412/37 Internal Hoist 8/95\n\nApplicability: All Bell Helicopter Textron 412 Series Helicopters with an internal hoist, P/N 214- 070-300-001/-101, installed on the right hand side.\n\nRequirement: 1. For each hoist operation, performed within the c.g. penalty region of Fig 1 of Bell Alert Service Bulletin (ASB) 412-95-83, log an additional four hours time in service against the main rotor yoke, mast and lower cone seat.\n\n    2. For hoist operations performed before 20 July 1995, log additional hours against the main rotor yoke, mast and lower cone seat in accordance with Bell ASB 412- 95-83.\n\n    3. Retire from service each main rotor yoke, mast and lower cone seat where the retirement life has been exceeded as a result of this calculation.\n\nCompliance: 1. Before the first flight after 20 July 1995.\n\n    2. Before 25 hours time in service or before 20 August 1995, whichever occurs first.\n\n    3. Within 150 hours time in service after completion of Requirement 2.\n\nBackground: Flight testing and fatigue analysis has shown that higher than expected loads are experienced on the main rotor yoke, mast and lower cone seat when operating the hoist with the aircraft c.g. within a certain region. A revised method of calculating the retirement lives for such operations is instituted.","sortOrder":0}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"Unauthenticated. Configure AI_GATEWAY_API_KEY or use a provider module. Learn more: https://ai-sdk.dev/unauthenticated-ai-gateway","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This Airworthiness Directive maintains its original narrow scope. It addresses a specific technical safety issue identified through flight testing and fatigue analysis regarding internal hoist operations on Bell 412 helicopters. The requirements remain tightly focused on the identified problem: accounting for additional fatigue loads on specific main rotor components when operating in a defined center of gravity range. There is no evidence of scope creep or expansion beyond the original safety purpose."},"complexity_factors":["Single, specific applicability criterion (one helicopter series with one specific part number)","Three sequential requirements with clear, numbered compliance deadlines","One external reference to a Bell Alert Service Bulletin (ASB 412-95-83) for technical details","No defined terms section—relies on standard aviation terminology","Straightforward conditional logic (if hoist operation in penalty region, then log additional hours)","Limited cross-referencing (only references the ASB for the c.g. penalty region diagram and calculation method)"],"plain_english_summary":"This safety directive requires operators of Bell 412 helicopters fitted with a specific right-side internal hoist to log extra flight hours against the main rotor yoke, mast, and lower cone seat when the hoist is used with the aircraft in a defined center-of-gravity penalty region. By accelerating component retirement (including retroactive accounting) it compensates for hidden fatigue from hoist operations to prevent premature main-rotor failure. Compliance and timely maintenance tracking are required."},"flash_summary":{"complexity_score":4,"scope_assessment":{"changed":false,"description":"The directive changes how retirement lives are calculated and requires additional logging and possible earlier retirements for specified components during certain hoist operations, but it does not broaden the population of affected aircraft beyond those with the listed hoist P/N on the right-hand side. It implements the technical fix described in the Background (Applicability; Requirements 1–3; Background)."},"complexity_factors":["Reliance on an external technical document for the critical boundary and calculation method (Bell ASB 412-95-83) (Requirement 1; Background).","Per-operation administrative burden: logging an additional four hours TIS each time a qualifying hoist operation is performed (Requirement 1).","Retroactive application: operators must log additional hours for past operations before 20 July 1995 (Requirement 2).","Potential for earlier-than-anticipated part retirement based on recalculated lives (Requirement 3), creating direct replacement costs and inventory planning needs.","Multiple components affected (main rotor yoke, mast, lower cone seat) requiring coordinated tracking of part lives and retirements (Applicability; Requirements 1–3).","Short, staged compliance deadlines with specific time windows (Compliance: items 1–3) increase scheduling and compliance-management complexity."],"plain_english_summary":"**Bell 412** helicopters fitted with the specified internal hoist (P/N 214-070-300-001/-101) on the right side must log an extra four hours time-in-service against the main rotor yoke, mast and lower cone seat for each hoist operation conducted with the aircraft in the c.g. penalty region (per Bell ASB 412-95-83). Operators must also apply the revised calculation retrospectively for operations before 20 July 1995 and retire components earlier if recalculated lives are exceeded. This imposes immediate record-keeping and potential replacement costs on operators."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-412-37-internal-hoist","history":"/api/acts/ad-bell-412-37-internal-hoist/history","analysis":"/api/acts/ad-bell-412-37-internal-hoist/analysis","conflicts":"/api/acts/ad-bell-412-37-internal-hoist/conflicts","importantCases":"/api/acts/ad-bell-412-37-internal-hoist/important-cases","documents":"/api/acts/ad-bell-412-37-internal-hoist/documents"}}