{"id":"F2006B04457","name":"AD/BELL 206/142 - Tailboom Assembly","slug":"ad-bell-206-142-tailboom-assembly","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":44294,"registerId":"commonwealth-F2006B04457-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"1","sectionType":"section","heading":"AD/BELL 206/142 - Tailboom Assembly","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 Canada (BHTC) 206 and Agusta Bell 206 Series Helicopters\n\nAD/BELL 206/142 Tailboom Assembly 13/98\n\nApplicability: BHTC Model 206L series helicopters as indicated below in the Requirement part of this directive. Tailboom assemblies modified in accordance with Technical Bulletin (TB) 206L-96-191, or BHT-206-SRM-1, section 6-3-4, with upper tailboom skin part number (P/N) 206-033-004-155 installed, are not affected by this directive.\n\nRequirement: To ensure the structural integrity of affected tailbooms, accomplish the following as applicable:\n\nPart 1. Applies to Model 206L series helicopters, serial number (S/N) 45001 through 51283, having unmodified tailboom assemblies P/N 206-033-004- 003, -011, -045, and -103.\n\nModify the tailboom between boom station BS 151.15 and 159.35 by installing doubler P/N 206-704-167-111 with clip P/N 206-033-407-119, and re-identify the tailboom by adding the suffix “FM” to the original part number as outlined in Part I of Alert Service Bulletin (ASB) 206L-87-47 Revision C.\n\nPart 2. Applies to the following Model 206L series helicopters:\n\nModel 206L S/N 45003 through 45153, and 46601 through 46617, Model 206L-1 S/N 45154 through 45790, and Model 206L-3 S/N 51001 through 51283; having tailboom assemblies of the following part numbers:\n\n206-033-004-003FM, \\-003FM1\n\n206-033-004-011FM, \\-011FM1, \\-011FM2, \\-011FM3\n\n206-033-004-103FM, \\-103FM1\n\n206-033-004-045FM\n\n    For tailbooms with a sheet metal tail rotor gearbox support, perform an Eddy Current inspection as in Part I of ASB 206L-97-107 Revision A.\n\n    b. For tailbooms with a cast tail rotor gearbox support P/N 206-033-426-001 and that do not have upper skin P/N 206-033-004-155 installed; install nutplate assemblies as per Part II of ASB 206L-97-107 Revision A.\n\nFor all Model 206L helicopters affected by Parts 1 and 2 above, replacement of the tailboom with any tailboom listed below constitutes terminating action for the requirements of Parts 1 and 2 of this directive:\n\n206-033-004-003FM2\n\n206-033-004-011FM4\n\n206-033-004-103FM2\n\nCOMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 \\- 105 CIVIL AVIATION SAFETY AUTHORITY\n\nSCHEDULE OF AIRWORTHINESS DIRECTIVES\n\n206-033-004-045FM1, \\-045FM2\n\n206-033-004-143, \\-143FM1\n\n206-033-004-175, \\-175FM1\n\n206-033-004-177\n\nNote: Transport Canada AD CF-98-27 refers.\n\nCompliance: Part 1. Within 200 hours time in service after 3 December 1998, but not later than 31 May 1999.\n\nPart 2.a. Within 100 hours time in service after 3 December 1998, and thereafter at intervals not to exceed 1,000 hours time in service.\n\n2.b. Within 200 hours time in service after 3 December 1998, but not later than 31 May 1999.\n\nThis Airworthiness Directive becomes effective on 3 December 1998.\n\nBackground: Cracking has been reported on tailbooms of earlier designs. If left undetected, these cracks could lead to failure of the tailboom and loss of control of the helicopter.","sortOrder":0}],"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":6,"scope_assessment":{"changed":false,"description":"This is a discrete, targeted safety directive addressing a specific structural defect in specific helicopter models. The scope remains tightly focused on tailboom integrity for the Bell 206L series as originally intended. The multiple parts and conditions reflect necessary technical granularity for different modification states of the affected fleet, not scope creep."},"complexity_factors":["Multiple overlapping applicability criteria combining serial number ranges, part numbers, and modification status","Nested conditional logic: Part 2 splits into 2.a and 2.b based on tail rotor gearbox support type (sheet metal vs cast)","Extensive use of manufacturer part numbers (P/N) and serial numbers (S/N) as definitional criteria - approximately 20+ specific part numbers referenced","Cross-references to external technical documents: Alert Service Bulletin (ASB) 206L-87-47 Revision C, ASB 206L-97-107 Revision A, Technical Bulletin TB 206L-96-191, and BHT-206-SRM-1 section 6-3-4","Terminating action clause requiring reference to alternative part numbers to cease compliance obligations","Dual compliance timelines (flight hours AND calendar dates) that differ between subsections","Suffix-based identification system (FM, FM1, FM2, etc.) requiring careful tracking of modification history"],"plain_english_summary":"This Airworthiness Directive requires owners/operators of specified Bell 206L-series helicopters to inspect and modify tailbooms after cracks were found that could cause in‑flight separation and loss of control. Older tailbooms must receive a reinforcing doubler and clip and be re‑marked; already‑modified tailbooms face recurring eddy‑current inspections or nutplate installations. Modifications are due within 200 flight hours or by 31 May 1999; inspections start within 100 hours and repeat every 1,000 hours. Replacing with newer tailbooms ends the requirements."},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":false,"description":"The directive sets requirements for identified serial numbers and tailboom part numbers and provides terminating replacement part numbers; it does not, within the supplied text, expand or narrow that applicability beyond those specified parts and serial ranges."},"complexity_factors":["Applicability tied to narrow serial number ranges and specific tailboom part numbers (Requirement Part 1 and Part 2) — operators must check historical records to determine applicability.","Multiple corrective options (modification, recurring inspection, nutplate installation, or replacement with terminating part numbers) increase choice and recordkeeping complexity (Parts 1 & 2).","Several distinct compliance timeframes and intervals: initial windows (100–200 hours TIS) and a recurring 1,000‑hour inspection interval (Compliance section; Part 2.a).","Physical tasks vary in skill and tooling: sheet‑metal mod (doubler/clip and re‑identification), eddy‑current NDT, and nutplate installation (Requirement Parts 1 and 2), affecting maintenance planning and cost.","Termination mechanism depends on installing specific replacement tailboom part numbers (listed terminating-action part numbers) — logistics and parts availability are relevant.","Cross‑references to Alert Service Bulletins (ASB 206L‑87‑47 Rev C and ASB 206L‑97‑107 Rev A) and an external Transport Canada AD increase dependency on external documents for procedural detail.","Exclusion for tailbooms already modified per certain TB/SRM references (upper skin P/N 206‑033‑004‑155) requires verification of previous modifications before taking action (Applicability note)."],"plain_english_summary":"Requires structural work on tailboom assemblies of specified Bell 206L-series helicopters: install a doubler and clip and re‑identify the tailboom, or — for other affected tailbooms — perform recurring eddy‑current inspections or install nutplate assemblies; replacing with listed tailboom part numbers ends the requirements. It applies to operators of the serial‑numbered helicopters named. Stated purpose: prevent tailboom cracking that could lead to tailboom failure and loss of control; the AD prescribes compliance windows and inspection intervals."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-206-142-tailboom-assembly","history":"/api/acts/ad-bell-206-142-tailboom-assembly/history","analysis":"/api/acts/ad-bell-206-142-tailboom-assembly/analysis","conflicts":"/api/acts/ad-bell-206-142-tailboom-assembly/conflicts","importantCases":"/api/acts/ad-bell-206-142-tailboom-assembly/important-cases","documents":"/api/acts/ad-bell-206-142-tailboom-assembly/documents"}}