ALERT SERVICE BULLETIN 206L-26-193

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ASB 206L-26-193 Page 1 of 4 Approved for public release. ALERT SERVICE BULLETIN 206L-26-193 3 August 2026 MODEL AFFECTED: 206L, 206L-1, 206L-3 and 206L-4 SUBJECT: SEGMENTED TAIL ROTOR DRIVESHAFTS 206- 040-365-001 / -117 / -125 AND AFT SHORT SHAFT 206-040-369-001 / -101 WITH BONDED ADAPTERS, REPLACEMENT OF HELICOPTERS AFFECTED: Serial numbers 45001 through 45153, 46601 through 46617, 45154 through 45790, 51001 through 51612, 52001 through 52223. COMPLIANCE: No later than 3 August 2029 DESCRIPTION: Bell has received reports of disbonding from the bonded adapters on segmented tail rotor driveshafts, specifically part numbers 206-040-365-001 and 206-040-369-101, which could result in loss of tail rotor drive and subsequent loss of helicopter control. This Alert Service Bulletin (ASB) mandates the replacement of all segmented tail rotor driveshafts 206-040-365-001 / -117 / -125 with bonded adapters and aft short shaft 206- 040-369-001 / -101 with bonded adapters in accordance with Technical Bulletin (TB) 206L-02-207. Applicability of this bulletin to any spare part shall be determined prior to its installation on an affected helicopter. APPROVAL: The engineering design aspects of this bulletin are Transport Canada Civil Aviation (TCCA) approved. ASB 206L-26-193 Page 2 of 4 Approved for public release. CONTACT INFO: For any questions regarding this bulletin, please contact: Bell Product Support Engineering Tel: 1-450-437-2862 / 1-800-363-8023 / productsupport@bellflight.com MANPOWER: Approximately 12 man-hours are required to complete this bulletin. This estimate is based on hands-on time and may vary with personnel and facilities available. WARRANTY: There is no warranty credit applicable for parts or labor associated with this bulletin. MATERIAL: Required Material: The following material is required for the accomplishment of this bulletin and may be obtained through your Bell Supply Center. The following material can be procured under Convenience Kit CT-206L-02-207-1. Part Number Nomenclature Qty (Note) 206-040-339-101 206-040-383-101 206-040-385-101 Bearing Aft Short Shaft Assy Segmented Shaft Assy 5 1 5 The following material can be procured under Convenience Kit CT-206L-02-207-2 (See note 1). Part Number Nomenclature Qty (Note) 206-706-114-001 206-040-475-101 AN4C7A Ring XMSN Driveshaft Spacer Bolt 1 1 (2) 4 MS21043-4 NAS1149C0463R NAS1149C0432R Nut Washer Washer 4 4 4 NOTES: 1. This kit is applicable to all aircraft where rotor brake kit is not installed. Rotor brake disc or transmission driveshaft spacer installation is mandatory with riveted tail rotor ASB 206L-26-193 Page 3 of 4 Approved for public release. driveshafts. Aircraft serial numbers 52001 through 52223 were delivered with rotor brake kit as basic aircraft. 2. Transmission driveshaft spacer 206-040-475-101 can be used instead of rotor brake disc 9440904 but rotor brake kit cannot be installed with transmission driveshaft spacer. Consumable Material: The following material is required to accomplish this bulletin, but may not require ordering, depending on the operator’s consumable material stock levels. This material may be obtained through your Bell Supply Center. Part Number Nomenclature Qty (Note) Reference * 2100-09016-02 CPC, MIL-PRF-16173 GR2 1 PT (1) C-104 * C-XXX numbers refer to the consumables list in the BHT-ALL-SPM, Standard Practices Manual NOTE 1: Quantity indicated is the format that the product is delivered in. Actual quantity required to accomplish the instructions in this bulletin may be less than what has been delivered. SPECIAL TOOLS: None required. WEIGHT AND BALANCE: Refer to Technical Bulletin 206L-02-207 ELECTRICAL LOAD DATA: Not affected. REFERENCES: BHT-206L-MM Maintenance Manual, Chapters 53, 66 and 71 BHT-206L1-MM Maintenance Manual, Chapters 53, 66 and 71 BHT-206L3-MM Maintenance Manual, Chapters 53, 65 and 71 BHT-206L4-MM Maintenance Manual, Chapters 53, 65 and 71 BHT-206L-SERIES-IPB, Illustrated Parts Breakdown, Chapter 65 Technical Bulletin 206L-02-207 PUBLICATIONS AFFECTED: BHT-206L-MM Maintenance Manual, Chapters 66 BHT-206L1-MM Maintenance Manual, Chapters 66 BHT-206L3-MM Maintenance Manual, Chapters 65 ASB 206L-26-193 Page 4 of 4 Approved for public release. BHT-206L4-MM Maintenance Manual, Chapters 65 BHT-206L-SERIES-IPB, Illustrated Parts Breakdown, Chapter 65 ACCOMPLISHMENT INSTRUCTIONS: -NOTE- As indicated in ASB 206L-20-184-RC Part II, replacing all bonded tail rotor driveshaft assemblies with riveted driveshaft assemblies constitutes the terminating action for the recurring proof load procedure specified in ASB 206-20-184-RC. 1. Prepare the helicopter for maintenance. 2. Remove aft fairing assembly, tail rotor driveshaft cover and tail rotor gearbox fairing. 3. Remove and discard all bonded tail rotor driveshafts. CAUTION Rotor brake disc or transmission driveshaft spacer installation is mandatory when installing riveted segmented driveshafts. The purpose of the rotor brake disc or transmission driveshaft spacer is to reduce the effect of the torsional load due to the stiffness of the riveted shafts. -NOTE- If Kaflex main driveshaft is installed on the aircraft, Kaflex rotor brake disc shall be installed. 4. Install riveted driveshafts (TB 206L-02-207). 5. Install aft fairing assembly, tail rotor driveshaft cover and tail rotor gearbox fairing. 6. Amend aircraft weight and balance in accordance with TB 206L-02-207. 7. Make an entry in the helicopter logbook and historical service records indicating compliance with this Alert Service Bulletin.