{"id":"F2005L02808","name":"AD/BELL 206/153 Amdt 3 - Tail Rotor Blade Trailing Edge Skin Cracks","slug":"ad-bell-206-153-amdt-3-tail-rotor-blade-trailing-edge-skin-cracks","collection":"legislative_instrument","jurisdiction":"commonwealth","status":"in_force","isInForce":true,"actNumber":null,"makingDate":null,"administeringDepartment":null,"currentVersion":{"id":37731,"registerId":"commonwealth-F2005L02808-current","compilationNumber":null,"startDate":"2026-04-01","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 206/153 Amdt 3 | Tail Rotor Blade TrailingEdge Skin Cracks | 11/2005 |\n| ---------------------- | ----------------------------------------- | ------- |\n\n| Applicability: | Model 206A and 206B helicopters, equipped with tail rotor blade, part numbers206-016-201-131 or 206-016-201-133, and Model 206L series helicopters equipped with tail rotor blade, part number 206-016-201-131; with serial numbers identified in Model 206A and 206B Alert Service Bulletin (ASB) 206-04-100, Revision C or a later Transport Canada approved revision, or Model 206L Series ASB 206L-04-127, Revision C or a later Transport Canada approved revision, as applicable.Agusta-Bell Model AB206A/B helicopters, equipped with tail rotor blades, part numbers 206-016-201-131 or 206-016-201-133; with serial numbers identified in Model AB206A/B Alert Bolletino Technico (ABT) 206-237.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |\n| -------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n| Requirement:   | Part A: Identification of Affected Tail Rotor Blades1. Verify if the rotorcraft is equipped with tail rotor blades identified in the “Component Affected” or “Helicopters Affected” section of the applicable ASB or ABT, listed in the Applicability part of this Directive. If the rotorcraft is equipped with an affected blade, enter the part number and serial number into the journey logbook. If not equipped with an affected blade, indicate that the rotorcraft is not equipped with blades affected by this Directive.2. If any spare blade is listed in the “Component Affected” or “Helicopters Affected” section of the applicable ASB or ABT, the blade is to be identified with a “Blue Diamond” decal as per Part II, of the applicable ASB or ABT.Part B: Initial and Recurring Check for Tail Rotor Blade CracksCheck the affected tail rotor blade for cracking in accordance with the instructions in Part I of the applicable ASB or ABT listed in the Applicability part of this Directive. If a crack is found, before further flight, replace the affected blade.Part C: Schedule 100 hour / Annual Inspection For Tail Rotor Blade CracksPerform a detail visual inspection of the tail rotor blade using a magnifying glass, in accordance with Part II of the applicable ASB or ABT listed in the Applicability part of this Directive. If a crack is found, before further flight, replace the affected blade. |\n|                | Part D: Terminating Inspection for Bell Helicopter Textron tail rotor bladesSend the affected tail rotor blades to the repair facility identified in Part III of the applicable ASB listed in the Applicability part of this Directive. Tail rotor blades found with unacceptable blade skin thickness are to be removed from service.Part E: New Skin Damage Limits for Bell Helicopter Textron tail rotor bladesInspect the tail rotor blades in accordance with Part IV of ASB 206-04-100 Revision C or ASB 206L-04-127 Revision C, or later Transport Canada approved revisions, as applicable.Part F: One-Time Inspections for Bell Helicopter Textron tail rotor bladesInspect the maintenance records of the affected blades to determine if the blades had been previously repaired following the inspection required by the previous issues of this Directive. If it has been repaired, contact the repair organisation to determine if the weight of the trailing edge root weight package had changed. If the weight package was increased, the tail rotor blade is to be sent for rebalancing in accordance with Part III of ASB 206-04-100 Revision C or ASB 206L-04-127 Revision C, or later Transport Canada approved revisions, as applicable.Note: Transport Canada AD CF-2004-05R2 refers.                                                                                                                                 |\n| Compliance:    | Part A.1. Before further flight after 6 May 2004, unless already accomplished.Part A.2. Before the installation of a spare blade.Part B. Before further flight after 6 May 2004, unless the initial inspection is already accomplished. Repeat thereafter at intervals specified in applicable ASB or ATB.Part C. At the next, and recurring, 100 hour scheduled inspection or annual inspection after 6 May 2004, whichever occurs first.Part D. Before 27 April 2007.Part E. At the next 100-hour scheduled inspection or annual inspection after 27 October 2005, whichever occurs first; or if damage is identified.Part F. At the next 100-hour scheduled inspection or annual inspection after 27 October 2005, whichever occurs first.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |\n\n|             | This Directive shall be entered on the Maintenance Release as maintenance required. The Requirement Part A.1.action, and Requirement Part B. “Recurring 3-Flight Hour Check,” identified in the applicable ASB or ABT listed in Applicability part of this Directive, may be performed and certified by the Pilot in Command who has been trained to do the Requirement Part A.1. action and Requirement Part B. inspection by an appropriately qualified person. In this case, a copy of the applicable ASB or ABT and this Directive is to be carried in the aircraft.The compliance times for Parts A, B, C, and D remain unchanged from the previous issue of this Directive.                                                                                                                                                                                                                                                                                                                                                                                                                                     |\n| ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |\n|             | This Amendment becomes effective on 27 October 2005.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |\n| Background: | Transport Canada received reports of three occurrences of skin cracks originating near the tail rotor blade trailing edge balance weight. Two of the occurrences resulted in loss of the weight and a strip of material along the trailing edge, leading to an imbalance, which caused fracture of three of the four tail rotor gearbox attachments. One of these occurrences resulted in the gearbox shifting that caused failure of the drive shaft, which resulted in loss of yaw control.Amendment 1 introduced Agusta-Bell AB206A/B helicopters to the requirements of this Directive.Amendment 2 introduced terminating action requiring affected blades to be inspected for acceptable tail rotor blade skin thickness.Amendment 3 is issued in response to a revision of the related Transport Canada AD, which introduces more stringent tail rotor skin damage limits, and re-balance requirements.Amendment 2 of this Directive became effective on 30 September 2004.Amendment 1 of this Directive became effective on 6 May 2004.The original issue of this Directive became effective on 26 March 2004. |\n\n![](image.001.png)  \nDavid Villiers  \nDelegate of the Civil Aviation Safety Authority\n\n16 September 2005","sortOrder":0},{"sectionNumber":"AD/BELL 206/153 Amdt 3","sectionType":"part","heading":"AD/BELL 206/153 Amdt 3","content":"## AD/BELL 206/153 Amdt 3","sortOrder":1},{"sectionNumber":"Tail Rotor Blade TrailingEdge Skin Crack","sectionType":"part","heading":"Tail Rotor Blade TrailingEdge Skin Cracks","content":"## Tail Rotor Blade Trailing  \nEdge Skin Cracks","sortOrder":2},{"sectionNumber":"11/2005","sectionType":"part","heading":"11/2005","content":"## 11/2005","sortOrder":3}],"analysis":{"kimi_summary":{"content_quality":"ok","complexity_score":6,"scope_assessment":{"changed":true,"description":"The original directive (March 2004) addressed cracking in Bell 206 tail rotor blades. Amendment 1 (May 2004) expanded scope to include Agusta-Bell AB206A/B helicopters. Amendment 2 (September 2004) added terminating actions requiring blade thickness inspections. Amendment 3 (October 2005) further expanded requirements to include new skin damage limits (Part E) and one-time inspections for rebalancing previously repaired blades (Part F). The directive has grown from simple recurring inspections to a comprehensive regime covering identification, recurring checks, terminating actions, damage limits, and historical repair verification."},"complexity_factors":["Multiple amendment layers (Amendment 3) with different effective dates and compliance deadlines for different parts (Parts A-D unchanged, Parts E-F new)","Cross-references to external documents: requires consultation of Transport Canada AD CF-2004-05R2, multiple Alert Service Bulletins (ASBs) with specific revision levels (Revision C or later), and Alert Bolletino Technico (ABT) 206-237","Conditional applicability based on four different helicopter models, two manufacturer types (Bell and Agusta-Bell), specific part numbers, and serial number ranges contained in external documents","Six distinct parts (A through F) with different compliance deadlines, inspection methods, and action requirements","Nested conditions for pilot-performed inspections: allowed only for specific parts (A.1 and B), requires specific training, and mandates carrying physical copies of referenced documents","Terminating action (Part D) with hard deadline (27 April 2007) versus recurring inspections with interval-based compliance","Historical tracking requirement (Part F) requiring review of maintenance records to determine prior repair status and weight changes"],"plain_english_summary":"This CASA Airworthiness Directive mandates inspection, marking, and possible replacement or repair of specific Bell/Agusta‑Bell 206 tail rotor blades after reports of trailing‑edge skin cracking near the balance weight that can cause weight loss, severe vibration and loss of yaw control.  \n\nIt affects owners/operators of listed 206/206L/AB206 helicopters with specified blade serial numbers; licensed maintenance engineers must do most checks (some short pilot‑performed checks allowed), and unsafe blades must be removed or reworked to prevent catastrophic failure."},"flash_summary":{"complexity_score":6,"scope_assessment":{"changed":true,"description":"This Amendment (Amdt 3) broadens and tightens the original directive. Compared with the original issue, the directive has expanded scope in several ways: (1) it added Agusta‑Bell AB206A/B helicopters (Amendment 1); (2) it introduced a terminating inspection and mandatory assessment of skin thickness and removal criteria (Amendment 2); and (3) this Amendment 3 adopts more stringent tail‑rotor skin damage limits and requires re‑balancing where prior repairs increased the trailing edge root weight package (Part E and Part F). It therefore moves beyond a simple requirement to inspect and replace cracked blades into new territory of defined damage limits, mandatory sending of blades to a named repair facility, marking of spares, and rebalancing obligations — increasing both the regulatory reach and the operational requirements on affected operators."},"complexity_factors":["Multiple aircraft models and two part numbers (206‑016‑201‑131 and 206‑016‑201‑133) with applicability limited to specific serial numbers listed in separate ASB/ABT documents","Six discrete requirement blocks (Parts A–F) each with different actions and conditions","Multiple and staggered compliance deadlines (before further flight; next 100‑hour or annual inspection; specific calendar cutoff dates such as 27 Oct 2005 and 27 Apr 2007)","Cross‑references to external documents (ASB 206‑04‑100 Rev C, ASB 206L‑04‑127 Rev C, ABT 206‑237 and Transport Canada AD CF‑2004‑05R2) whose later approved revisions alter inspection limits and procedures","Conditional permission for Pilots‑in‑Command to perform and certify certain inspections subject to training and carriage of documents (adds conditional certification logic)","Terminating action that mandates sending blades to a specified repair facility (introduces operational dependency on an external organisation)","Combination of recurring inspections (short‑interval and scheduled detailed checks) and a one‑time administrative/records check with potential rebalancing requirement","Amendment history (original directive plus Amendments 1–3) showing added scope and tightened thresholds, increasing interpretive complexity"],"plain_english_summary":"**What this instrument does (mechanically)\n\n- Requires operators of specified Bell/Agusta‑Bell 206 helicopters that have certain tail‑rotor blade part numbers and listed serial numbers to identify and log those blades (Part A).  Spare blades that appear on the affected lists must be marked with a \"Blue Diamond\" decal (Part A.2).  \n\n- Requires immediate initial and recurring inspections for cracks in the tail‑rotor blade trailing‑edge skin, and replacement of any cracked blade before further flight (Part B).  \n\n- Requires a more detailed visual inspection (magnifying glass) at the next scheduled 100‑hour or annual inspection, and recurring at those intervals, with replacement before further flight if a crack is found (Part C).  \n\n- Requires a terminating action by a stated deadline: affected blades must be sent to the repair facility identified in the applicable Alert Service Bulletin (ASB) for assessment/repair; blades with unacceptable skin thickness must be removed from service (Part D).  \n\n- Adopts new, stricter skin damage limits and requires inspections under the limits specified in the ASBs (Part E).  \n\n- Requires a one‑time check of maintenance records to see if affected blades were previously repaired under this directive; if a repair increased the trailing edge root weight package the blade must be rebalanced per the ASB (Part F).  \n\n- Permits a trained Pilot‑in‑Command to perform and certify certain short‑interval inspections (the initial identification and the recurring 3‑flight‑hour crack check), provided the pilot has been trained by an appropriately qualified person and carries a copy of the ASB and this Directive in the aircraft.  \n\n- Requires the directive and its required actions to be recorded on the aircraft maintenance release.  Compliance times differ by part (before further flight, next 100‑hour/annual inspection, or specified calendar deadlines) as set out in the directive.\n\n**Who this affects\n\n- Owners and operators of Model 206A, 206B and 206L series Bell helicopters, and Agusta‑Bell AB206A/B, that are equipped with tail‑rotor blades having part numbers 206‑016‑201‑131 or 206‑016‑201‑133 and whose blade serial numbers are listed in the applicable ASB/ABT (the Alert Service Bulletin or Alert Bolletino Technico referenced in the Applicability).\n\n- Maintenance organisations, repair facilities and any person authorised to perform maintenance who must follow or record the required inspections, repairs, marking and maintenance‑release entries.\n\n- Pilots who are trained and authorised to perform the short‑interval inspections may be asked to carry out and sign off those checks.\n\n**Why it matters (stated rationale and observed risk)\n\n- Transport Canada reported three occurrences where skin cracks at the trailing edge balance‑weight area led to loss of the weight and trailing‑edge material, producing a rotor imbalance.  In two cases gearbox attachments fractured; in one case the gearbox shifted, the drive shaft failed and yaw control was lost.  The directive’s stated purpose is to detect and remove cracked or damaged tail‑rotor blades and to ensure blades meet skin‑thickness and balance limits so those failure modes do not occur (Background; Parts B–F).\n\n**Practical effects, costs and incentives (mechanics and tradeoffs)\n\n- Direct costs fall to operators: time for repeated inspections (initial, recurring short‑interval checks and scheduled 100‑hour/annual inspections), replacement of cracked blades, and shipping/repair costs when blades must be sent to the specified repair facility (Parts B, C, D, F).  Downtime while awaiting repair or replacement will also be borne by operators.\n\n- The directive concentrates certain repair work by specifying the repair facility named in the ASB for the terminating action (Part D). That channels business to a particular facility and may increase turnaround time or price if capacity is limited.  The ASB can be revised later, but until then the named facility controls the terminating pathway.\n\n- Allowing a trained pilot to perform and certify short‑interval inspections reduces immediate maintenance labour costs and can speed compliance, but shifts responsibility and training costs onto operators and requires record retention and carriage of the ASB/directive on the aircraft (maintenance‑release entry requirement).\n\n- The one‑time record check and the rebalance requirement (if a prior repair increased the trailing edge root weight package) impose an additional administrative/compliance cost and potentially further repair or re‑balancing work (Part F).\n\n- Operators can avoid future compliance costs only if they can lawfully fit non‑affected blade part numbers or serial‑numbered blades; the directive is tied to specific P/Ns and serial numbers identified in the ASB/ABT (Applicability).\n\n**Implementation and compliance risk\n\n- The directive relies on accuracy and availability of the referenced ASBs/ABTs and on Transport Canada’s corresponding AD. Operators must use the ASB/ABT revision that is applicable and Transport Canada‑approved; later approved revisions change inspection limits and procedures (Applicability; Parts E and F).  \n\n- The multiple, different compliance deadlines (before further flight; next 100‑hour or annual; specific calendar cut‑offs) increase administrative complexity and risk of missed actions if recordkeeping is poor (Compliance section).\n\n**Who decides and what behaviour changes\n\n- Regulators (CASA in Australia, coordinated with Transport Canada ADs and the ASBs) require the actions; operators must decide how to schedule inspections, where to send blades for terminating action, and whether to authorise/training pilots to perform short‑interval checks.  \n\n- Behaviour changes include more frequent inspections of the tail‑rotor trailing edge, marking and logging of affected spares, sending blades to the designated repair facility for terminating action, and, where applicable, rebalancing blades after prior repairs.\n\n**Source claims vs. tradeoffs\n\n- The directive’s stated safety goal (preventing loss of yaw control and mechanical failures caused by trailing‑edge skin cracks) is supported by the reported occurrences described in the Background. The tradeoffs are concrete: increased inspection, repair, replacement and administrative costs and potential concentration of repair work at a named facility in exchange for reduced risk of in‑flight failures.  Compliance choices (e.g. pilot‑performed checks, replacing with unaffected blades) affect operators’ immediate costs and operational availability.\n\n(References in the directive: Parts A–F, Applicability, Compliance and Background.)"},"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"}},"importantCases":[],"_links":{"self":"/api/acts/ad-bell-206-153-amdt-3-tail-rotor-blade-trailing-edge-skin-cracks","history":"/api/acts/ad-bell-206-153-amdt-3-tail-rotor-blade-trailing-edge-skin-cracks/history","analysis":"/api/acts/ad-bell-206-153-amdt-3-tail-rotor-blade-trailing-edge-skin-cracks/analysis","conflicts":"/api/acts/ad-bell-206-153-amdt-3-tail-rotor-blade-trailing-edge-skin-cracks/conflicts","importantCases":"/api/acts/ad-bell-206-153-amdt-3-tail-rotor-blade-trailing-edge-skin-cracks/important-cases","documents":"/api/acts/ad-bell-206-153-amdt-3-tail-rotor-blade-trailing-edge-skin-cracks/documents"}}