{"id":"F2006L03616","name":"AD/BELL 430/9 - Yaw Synchro Resolver Shaft Control Arm Screw","slug":"ad-bell-430-9-yaw-synchro-resolver-shaft-control-arm-screw","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":137303,"registerId":"commonwealth-F2006L03616-current","compilationNumber":null,"startDate":"2026-04-03","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Bell Helicopter Textron Canada (BHTC) 43","sectionType":"division","heading":"Bell Helicopter Textron Canada (BHTC) 430 Series Helicopters","content":"### Bell Helicopter Textron Canada (BHTC) 430 Series Helicopters\n\n| AD/BELL 430/9 | Yaw Synchro Resolver ShaftControl Arm Screw | 12/2006 |\n| ------------- | ------------------------------------------- | ------- |\n\n| Applicability: | Model 430 helicopters, serial numbers 49001 through 49018, 49020 through 49043, and 49045 through 49051.                                                                                                                                                                          |\n| -------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Install screws part number 1352-04-8P and guard brackets in accordance with the Accomplishment Instructions of BHTC Alert Service Bulletin 430-99-11, or later Transport Canada approved revision.Note: Transport Canada AD CF-99-26 refers.                                      |\n| Compliance:    | Unless already accomplished, before 23 December 2006.                                                                                                                                                                                                                             |\n|                | This Airworthiness Directive becomes effective on 23 November 2006.                                                                                                                                                                                                               |\n| Background:    | A yaw control channel malfunctioned during a check for freedom of controls following maintenance. The screw that clamps the control arm to the yaw synchro resolver shaft was loose, allowing the control arm to separate from the shaft and to jam against an airframe stringer. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n12 October 2006","sortOrder":0},{"sectionNumber":"AD/BELL 430/9","sectionType":"part","heading":"AD/BELL 430/9","content":"## AD/BELL 430/9","sortOrder":1},{"sectionNumber":"Yaw Synchro Resolver ShaftControl Arm Sc","sectionType":"part","heading":"Yaw Synchro Resolver ShaftControl Arm Screw","content":"## Yaw Synchro Resolver Shaft  \nControl Arm Screw","sortOrder":2},{"sectionNumber":"12/2006","sectionType":"part","heading":"12/2006","content":"## 12/2006","sortOrder":3}],"analysis":{"flash_summary_failed":{"failed":true,"reason":"A positive credit balance is required for all requests, including BYOK, so fallback providers remain available. Add credits at https://vercel.com/d?to=%2F%5Bteam%5D%2F%7E%2Fai%3Fmodal%3Dtop-up to continue.","source":"analysis-cron"},"kimi_summary":{"content_quality":"ok","complexity_score":2,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific mechanical defect in a limited fleet of helicopters. There is no evidence of scope creep; it targets exactly the safety issue identified in the background (loose yaw synchro resolver shaft screw) and mandates the precise fix recommended by the manufacturer."},"complexity_factors":["Single, specific mechanical fault addressed","Only 43 aircraft affected with clearly listed serial numbers","One primary compliance action (install specific screws and brackets)","Single cross-reference to manufacturer service bulletin and Transport Canada AD","Simple deadline structure (one fixed date)","No nested exceptions, conditional logic, or defined terms section","Document is approximately 200 words with minimal formatting complexity"],"plain_english_summary":"CASA has issued a mandatory Airworthiness Directive requiring owners/operators of 43 Bell 430 helicopters (specified serial numbers) to install new screws (P/N 1352-04-8P) and protective guard brackets per Bell Alert Service Bulletin 430-99-11 to prevent a yaw synchro resolver screw coming loose and jamming the yaw control.\n\nWork must be completed before 23 December 2006; affected helicopters are grounded until the corrective action is done."},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"Scope appears unchanged from the instrument's original purpose: it targets the listed Bell 430 serial numbers and prescribes installation of specified screws and guard brackets per the referenced service bulletin. No expansion or narrowing of affected aircraft or actions is indicated in the text supplied."},"complexity_factors":["Narrow applicability tied to specific serial-number ranges (precise scope limits applicability and compliance population)","Technical specificity: requires a particular part number (P/N 1352-04-8P) and installation procedure","Dependence on an external document: compliance requires following BHTC Alert Service Bulletin 430-99-11 or a later Transport Canada–approved revision","Fixed compliance deadline and effective date (administrative time pressure for operators)","Regulatory cross-reference to Transport Canada AD CF-99-26 (multiple-authority linkage)","Cost and operational impact borne by aircraft owners/operators (parts and labour)","Low regulatory discretion: requirement is prescriptive but allows only later TC‑approved bulletin revisions"],"plain_english_summary":"Requires owners/operators of Bell 430 helicopters (serial numbers 49001–49018, 49020–49043, 49045–49051) to install P/N 1352-04-8P screws and guard brackets in accordance with BHTC Alert Service Bulletin 430‑99‑11 (or a later Transport Canada–approved revision) to stop the yaw control arm separating from the yaw synchro resolver shaft. Effective 23 Nov 2006; compliance required by 23 Dec 2006.\n\nCosts fall to owners/operators to procure parts and fit them; the regulator enforces compliance and permits only TC‑approved bulletin revisions."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-430-9-yaw-synchro-resolver-shaft-control-arm-screw","history":"/api/acts/ad-bell-430-9-yaw-synchro-resolver-shaft-control-arm-screw/history","analysis":"/api/acts/ad-bell-430-9-yaw-synchro-resolver-shaft-control-arm-screw/analysis","conflicts":"/api/acts/ad-bell-430-9-yaw-synchro-resolver-shaft-control-arm-screw/conflicts","importantCases":"/api/acts/ad-bell-430-9-yaw-synchro-resolver-shaft-control-arm-screw/important-cases","documents":"/api/acts/ad-bell-430-9-yaw-synchro-resolver-shaft-control-arm-screw/documents"}}