Airworthiness Directive · Amendment 39-22188 · Tail rotor drive shaft
Bell Textron Canada Limited Helicopters
This AD applies to Bell Textron Canada Limited Model 206, 206A, 206A-1 (OH-58A), 206B, 206B-1, 206L, 206L-1, 206L-3, and 206L-4 helicopters, all serial numbers, certificated in any category.
The FAA is superseding airworthiness directive (AD) 2021-26- 08, which applied to certain Bell Textron Canada Limited Model 206, 206A, 206A-1, 206B, 206B-1, 206L, 206L-1, 206L-3, and 206L-4 helicopters. AD 2021-26-08 required removing certain nuts from service; installing newly designed nuts; applying a specific torque, and a torque stripe to each newly installed nut; after the installation of each newly designed nut, inspecting the torque; and depending on the inspection results, either applying a torque stripe, or performing further inspections and removing certain parts from service. AD 2021- 26-08 also prohibited installing any affected nut on any tail rotor drive shaft (TRDS) disc pack (Thomas) coupling. Since the FAA issued AD 2021-26-08, the FAA determined certain torque values and part numbers (P/Ns) need to be revised. This AD was prompted by reports of cracked or missing nuts installed on the TRDS Thomas couplings and the need to revise certain torque values and P/Ns in AD 2021-26-08. This AD requires removing certain nuts from service; installing newly designed nuts; applying torque and a torque stripe; and additional corrective actions if necessary. This AD also prohibits installing any affected nut on any TRDS Thomas coupling, as specified in a Transport Canada AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.
Except as specified in paragraphs (h) and (i) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, Transport Canada AD CF-2020-15, dated May 13, 2020 (Transport Canada AD CF-2020-15).
(1) Where Transport Canada AD CF-2020-15 requires compliance in terms of air time, this AD requires using hours time-in-service (TIS).
(2) Where Transport Canada AD CF-2020-15 refers to the effective dates specified in paragraphs (h)(2)(i) and (ii) of this AD, this AD requires using the effective date of this AD.
(i) October 9, 2019 (the effective date of Transport Canada AD CF-2019-34, dated September 25, 2019).
(ii) The effective date of Transport Canada AD CF-2020-15.
(3) Where Transport Canada AD CF-2020-15 defines Group 1 helicopters as those models “that have not been modified by installing STC SH2750NM or STC SH99-202,” replace “that have not been modified by installing STC SH2750NM or STC SH99-202” with “that have not been modified by installing STC SH2750NM.”
(4) Where Transport Canada AD CF-2020-15 defines Group 4 helicopters as those models “that have been modified by installing STC SH2750NM or STC SH99-202,” replace “that have been modified by installing STC SH2750NM or STC SH99-202” with “that have been modified by installing STC SH2750NM.”
(5) Where Transport Canada AD CF-2020-15 requires compliance within 600 hours air time or 24 months, whichever occurs first, this AD requires compliance within 600 hours TIS only and does not allow a compliance time of 24 months.
(6) Where any paragraph of Transport Canada AD CF-2020-15 specifies to replace part number (P/N) MS21042 nuts with P/N NAS9926 nuts, this AD requires removing P/N MS21042 nuts from service and replacing with P/N NAS9926 nuts.
(7) Where any paragraph of any service information referenced in Transport Canada AD CF-2020-15 specifies to replace P/N MS21042L4 nuts with P/N 90-132L4 nuts, this AD requires removing P/N MS21042L4 nuts from service and replacing with P/N 90-132L4 nuts, in accordance with Air Comm Corporation Service Bulletin SB 206EC-092619, Revision NC, dated September 26, 2019 (SB 206EC-092619 Rev NC).
(8) Where any paragraph of any service information referenced in Transport Canada AD CF-2020-15 specifies to replace P/N MS21042L5 nuts with P/N 90-132L5 nuts, this AD requires removing P/N MS21042L5 nuts from service and replacing with P/N 90-132L5 nuts, in accordance with SB 206EC-092619 Rev NC.
(9) Where any paragraph of any service information referenced in Transport Canada AD CF-2020-15 specifies if any P/N MS21042L4 nuts are found loose or damaged, report at which location and provide the information to Product Support Engineering at productsupport@bellflight.com, this AD requires if any P/N MS21042L4 nuts are found loose or damaged, before further flight, inspecting each TRDS Thomas coupling, including each bolt, nut, and washer, for any elongated holes, fretting on the fasteners, and damaged fasteners. If there is any elongated hole, fretting on the fasteners, or damaged fasteners, this AD requires before further flight, removing from service each affected part and replacing it with an airworthy part.
Although the service information referenced in Transport Canada AD CF-2020-15 specifies to submit certain information to the manufacturer, this AD does not include that requirement.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
