{"id":"F2006L02488","name":"AD/BELL 206/163 - Vertical Stabiliser Supports and Vertical Stabiliser","slug":"ad-bell-206-163-vertical-stabiliser-supports-and-vertical-stabiliser","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":59681,"registerId":"commonwealth-F2006L02488-current","compilationNumber":null,"startDate":"2026-04-02","status":"InForce","reasons":null,"registeredAt":null},"sections":[{"sectionNumber":"Bell Helicopter Textron Canada (BHTC) 20","sectionType":"division","heading":"Bell Helicopter Textron Canada (BHTC) 206 and Agusta Bell 206 Series Helicopters","content":"### Bell Helicopter Textron Canada (BHTC) 206 and Agusta Bell 206 Series Helicopters\n\n| AD/BELL 206/163 | Vertical Stabiliser Supportsand Vertical Stabiliser | 9/2006 |\n| --------------- | --------------------------------------------------- | ------ |\n\n| Applicability: | Model 206 A/B helicopters, serial numbers 004 through 3906, equipped with two-piece fin supports, part numbers 206-031-417-003/-007 and 206-031-418-001/-005.                                                                                                                                                                                                                                                                                                                                                                                                                                         |\n| -------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | 1. Accomplish the inspection and restoration as indicated for the applicable vertical stabiliser and its supports in accordance with Bell Helicopter Textron Canada Alert Service Bulletin 206-06-107, or later Transport Canada approved revision.2. Amend the maintenance program as specified in BHT-206A/B-Series-MM, Revision 4, to require a recurring torque check of the vertical stabiliser attaching hardware at the scheduled 100-hr / annual inspection.Note: Transport Canada AD CF-2006-12 refers.                                                                                      |\n| Compliance:    | At the next scheduled 100-hour or annual inspection, but not later than 3 months after 31 August 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n|                | This Airworthiness Directive becomes effective on 31 August 2006.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n| Background:    | Investigation of a recent accident revealed that the vertical stabiliser (fin) supports had failed. During the investigation it was observed that the tail boom vertical fin supports and the adjoining mating surface of the vertical fin inserts were painted. Painting of these surfaces is not appropriate since the paint coating may affect the stability or permanence of the installation. In addition, paint on the supports may affect inspection of the joint. The corrective action required by this Directive is specific to the earlier design tail boom that utilised forged supports. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n19 July 2006","sortOrder":0},{"sectionNumber":"AD/BELL 206/163","sectionType":"part","heading":"AD/BELL 206/163","content":"## AD/BELL 206/163","sortOrder":1},{"sectionNumber":"Vertical Stabiliser Supportsand Vertical","sectionType":"part","heading":"Vertical Stabiliser Supportsand Vertical Stabiliser","content":"## Vertical Stabiliser Supports  \nand Vertical Stabiliser","sortOrder":2},{"sectionNumber":"9/2006","sectionType":"part","heading":"9/2006","content":"## 9/2006","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"},"flash_summary":{"complexity_score":3,"scope_assessment":{"changed":false,"description":"The directive is narrowly framed around the original safety problem identified in the accident investigation (failure of the vertical stabiliser supports and concerns about painted mating surfaces). The measures—inspect/restore per a Bell service bulletin and add recurring torque checks to the maintenance programme—are corrective and directly tied to that problem. It does not broaden the regulatory reach beyond those affected serial numbers, parts, and the specific maintenance actions, so it has not expanded significantly beyond its original safety‑corrective purpose."},"complexity_factors":["Applicability limited to a serial-number range (serials 004–3906) with specific part numbers for two-piece fin supports (4 part numbers)","Action requires following external documents: Bell Alert Service Bulletin 206-06-107 (or later Transport Canada‑approved revision) and BHT-206A/B-Series-MM Revision 4","Two distinct mandated actions: a one‑off inspection/restoration and a recurring torque‑check added to the maintenance program","Compliance timing includes both “next scheduled 100‑hr/annual inspection” and an absolute deadline (“no later than 3 months after 31 Aug 2006”), creating a dual-timing condition","Cross-reference to Transport Canada AD CF-2006-12 and reliance on later approved revisions increases cross-jurisdictional and version-management complexity"],"plain_english_summary":"**What this instrument does (mechanically)**\n\n- It applies to Bell/Agusta Bell 206 A/B helicopters, serial numbers 004 through 3906, that have the older two-piece vertical fin (stabiliser) supports (part numbers 206-031-417-003/-007 and 206-031-418-001/-005).\n- It requires two things:\n  - Inspect and restore the vertical stabiliser and its supports in accordance with Bell Helicopter Textron Canada Alert Service Bulletin 206-06-107 (or a later revision approved by Transport Canada). (Requirement)\n  - Amend the operator’s maintenance program (per BHT-206A/B-Series-MM, Revision 4) to include a recurring torque check of the vertical stabiliser attaching hardware at each scheduled 100‑hour or annual inspection. (Requirement)\n- Timing: the work must be done at the next scheduled 100‑hour or annual inspection, and in any case no later than three months after 31 August 2006. The directive took effect on 31 August 2006. (Compliance)\n\n**Who this affects**\n\n- Owners and operators of the specified Bell 206 A/B helicopters (serials 004–3906) that are fitted with the older two‑piece fin supports. (Applicability)\n- Maintenance organisations and mechanics who perform inspections, restorations and maintenance-program amendments for those helicopters.\n\n**Why it matters (safety and operational mechanics)**\n\n- The directive follows an accident investigation that found failure of the vertical stabiliser supports. Investigators observed paint on the mating surfaces between the tail boom supports and the fin inserts; the paint can interfere with the joint’s stability and make inspection harder. (Background)\n- The inspection and restoration step is intended to remove or remedy issues arising from the painted mating surfaces and any related deterioration. The recurring torque checks are intended to ensure the stabiliser attaching hardware remains correctly tightened over time. (Requirement)\n\n**Who pays, who decides, and what changes in behaviour**\n\n- Aircraft owners/operators pay the costs: inspection labour, any restoration or replacement parts, and aircraft downtime. (Requirement, Compliance)\n- The Civil Aviation Safety Authority (CASA) issued the directive and requires compliance by reference to the Bell Alert Service Bulletin and the specified maintenance manual revision; the service bulletin and maintenance manual set the technical steps that maintenance providers must follow. (Requirement)\n- Operators must update their maintenance programmes to add the recurring torque check and must instruct maintenance providers to carry out the inspection/restoration per the service bulletin. Maintenance providers must carry out the work at the next scheduled 100‑hour or annual inspection (or within three months). (Requirement, Compliance)\n\n**Costs, incentives and trade‑offs**\n\n- Direct costs: labour for inspection and restoration; materials or replacement parts if corrosion/damage is found; administrative cost to amend maintenance programmes and record recurring checks. (Requirement)\n- Opportunity cost: time the helicopter is unavailable while inspected/restored; scheduling pressure for operators approaching the next 100‑hour/annual inspection.\n- Incentives: compliance is required to maintain airworthiness; non‑compliance risks regulatory action and continued risk of structural failure. The recurring-check requirement creates an ongoing (recurring) maintenance cost to reduce the probability of future failures. (Requirement)\n\n**Implementation risk and compliance burden**\n\n- Implementation depends on correct execution of the service-bulletin tasks and accurate torque checking at the specified intervals. If the restoring steps or torque checks are not properly done, the safety objective may not be achieved. (Requirement)\n- Administrative burden is modest but recurring: operators must amend maintenance manuals and ensure the torque check is performed and recorded at every 100‑hr/annual inspection. (Requirement)\n\n**Effects on private businesses and markets**\n\n- Independent maintenance organisations can perform the required work so long as they follow the approved service bulletin and maintenance-program changes. The directive does not limit who may carry out the work, but it does require following the specified technical documents. (Requirement)\n- Costs are concentrated on owners/operators of the affected serial-number range; safety benefits (reduced risk of stabiliser failure) are distributed to passengers, pilots and the public using airspace where those helicopters operate. (Applicability, Background)\n\n**Cross-references and regulatory context**\n\n- The directive references Bell Helicopter Textron Canada Alert Service Bulletin 206-06-107 and BHT-206A/B-Series-MM Revision 4 for the technical method and the recurring inspection schedule. It also refers to a Transport Canada AD (CF-2006-12) as related regulatory action. (Requirement, Note)\n\n**Bottom line**\n\nThis is a targeted airworthiness directive addressing a discovered failure mode in older-design Bell 206 tail booms. It mandates a one‑time inspection/restoration per the Bell service bulletin and an ongoing torque‑check requirement built into the maintenance programme. Owners/operators bear the direct costs; compliance is required to maintain airworthiness and reduce the risk of vertical stabiliser failure. (Applicability, Requirement, Compliance, Background)"},"kimi_summary":{"content_quality":"ok","complexity_score":3,"scope_assessment":{"changed":false,"description":"This AD maintains its original narrow scope — addressing a specific safety defect in particular Bell helicopter models. The directive remains tightly focused on the vertical stabiliser support failure issue identified in the accident investigation, with no evidence of scope creep into unrelated systems or aircraft types."},"complexity_factors":["Single, specific technical requirement with clear applicability criteria (specific helicopter models, serial number range, and part numbers)","Two straightforward compliance actions: one-time inspection/restoration and recurring maintenance program amendment","Single cross-reference to Transport Canada AD CF-2006-12 and Bell service bulletin","Clear deadline with alternative compliance paths (next scheduled inspection OR 3-month hard deadline)","No nested exceptions, conditional logic, or extensive defined terms","Technical aviation terminology requires some domain knowledge but is standard for the industry"],"plain_english_summary":"This CASA Airworthiness Directive requires owners/operators of Bell 206 A/B helicopters (S/N 004–3906) with two‑piece fin supports to inspect and repair the vertical stabiliser supports because paint on mating surfaces caused a crash risk by preventing proper installation and hiding damage.\n\nAffected operators must follow Bell’s service bulletin and amend maintenance programs to perform torque checks every 100 flight hours or annually, by the next inspection or within three months of 31 August 2006."}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-206-163-vertical-stabiliser-supports-and-vertical-stabiliser","history":"/api/acts/ad-bell-206-163-vertical-stabiliser-supports-and-vertical-stabiliser/history","analysis":"/api/acts/ad-bell-206-163-vertical-stabiliser-supports-and-vertical-stabiliser/analysis","conflicts":"/api/acts/ad-bell-206-163-vertical-stabiliser-supports-and-vertical-stabiliser/conflicts","importantCases":"/api/acts/ad-bell-206-163-vertical-stabiliser-supports-and-vertical-stabiliser/important-cases","documents":"/api/acts/ad-bell-206-163-vertical-stabiliser-supports-and-vertical-stabiliser/documents"}}