# Proposed AD FAA-2021-0728: Bell Textron Canada Limited

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2021-26-08
- Products: Bell Textron Canada
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: September 14, 2021, 86 FR 51038
- Comments due: October 29, 2021
- Became: [AD 2021-26-08](https://openairdocs.org/ad/2021-26-08)
- Docket: FAA-2021-0728 (https://www.regulations.gov/docket/FAA-2021-0728, where comments are filed)
- Project: MCAI-2020-00656-R
- FR document: 2021-19605
- Official PDF: https://openairdocs.org/files/sha256/be/d9/bed9cbcc1cd3688e7bc2d994d146f25f9920b6ca5d85075c5a732ea0808c6589 (from https://www.govinfo.gov/content/pkg/FR-2021-09-14/pdf/2021-19605.pdf)
- Federal Register: https://www.federalregister.gov/documents/2021/09/14/2021-19605/airworthiness-directives-bell-textron-canada-limited
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/DDC5F3BB50D8D8E686258751004B3CCD.0001
- Page: https://openairdocs.org/proposed/FAA-2021-0728

## Summary

The FAA proposes to adopt a new airworthiness directive (AD) for certain Bell Textron Canada Limited Model 206, 206A, 206A-1, 206B, 206B-1, 206L, 206L-1, 206L-3, and 206L-4 helicopters. This proposed AD was

((Page 51039))

prompted by reports of cracked or missing nuts on the tail rotor drive shaft (TRDS) disc pack (Thomas) couplings. This proposed AD would require removing certain nuts from service, installing newly designed nuts, and applying a specific torque and a torque stripe to each newly installed nut. This proposed AD would then require, 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. Finally, this proposed AD would prohibit installing any affected nut on any TRDS Thomas coupling. The FAA is proposing this AD to address the unsafe condition on these products.

## Notices in this docket

- Sep 14, 2021: Notice of proposed rulemaking (NPRM). (first notice), FR document 2021-19605, comments due Oct 29, 2021 (https://www.federalregister.gov/documents/2021/09/14/2021-19605/airworthiness-directives-bell-textron-canada-limited)

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