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Federal Register / Vol. 86, No. 184 / Monday, September 27, 2021 / Rules and Regulations Issued on August 26, 2021.
Lance T. Gant, Director, Compliance & Airworthiness Division, Aircraft Certification Service.

Examining the AD Docket
FR Doc. 202120830 Filed 92421; 8:45 am BILLING CODE 491013P

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration 14 CFR Part 39
Docket No. FAA20210513; Project Identifier 2018SW116AD; Amendment 3921717; AD 20211816
RIN 2120AA64

Airworthiness Directives; Bell Textron Canada Limited Type Certificate Previously Held by Bell Helicopter Textron Canada Limited Helicopters Federal Aviation Administration FAA, DOT.
ACTION: Final rule.
AGENCY:

The FAA is adopting a new airworthiness directive AD for certain Bell Textron Canada Limited Bell Model 429 helicopters. This AD was prompted by reports of tail rotor gearbox assemblies found loose on the gearbox support. This AD requires repetitive torque checks of the tail rotor gearbox attachment hardware, and corrective action if necessary. The FAA is issuing this AD to address the unsafe condition on these products.
DATES: This AD is effective November 1, 2021.
The Director of the Federal Register approved the incorporation by reference of a certain document listed in this AD
as of November 1, 2021.
ADDRESSES: For service information identified in this final rule, contact Bell Textron Canada Limited, 12,800 Rue de lAvenir, Mirabel, Quebec J7J 1R4, Canada; telephone 14504372862 or 18003638023; fax 14504330272;
email productsupport@bellflight.com; or at https www.bellflight.com/support/
contact-support. You may view the referenced service information at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N321, Fort Worth, TX
76177. For information on the availability of this material at the FAA, call 8172225110. It is also available at https www.regulations.gov by searching for and locating Docket No.
FAA20210513.

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SUMMARY:

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You may examine the AD docket at https www.regulations.gov by searching for and locating Docket No.
FAA20210513; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, the Transport Canada AD, any comments received, and other information. The street address for Docket Operations is U.S. Department of Transportation, Docket Operations, M
30, West Building Ground Floor, Room W12140, 1200 New Jersey Avenue SE, Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT:
Darren Gassetto, Aerospace Engineer, COS Program Management Section, FAA, Operational Safety Branch, Compliance & Airworthiness Division, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516
2287323; email Darren.Gassetto@
faa.gov.
SUPPLEMENTARY INFORMATION:

Background The FAA issued a notice of proposed rulemaking NPRM to amend 14 CFR
part 39 by adding an AD that would apply to certain Bell Textron Canada Limited Bell Model 429 helicopters.
The NPRM published in the Federal Register on June 28, 2021 86 FR 33918.
In the NPRM, the FAA proposed to require repetitive torque checks of the tail rotor gearbox attachment hardware, and corrective action if necessary. The NPRM was prompted by Canadian AD
CF201835, dated December 19, 2018
Canadian AD CF201835, issued by Transport Canada, which is the aviation authority for Canada, to correct an unsafe condition for Bell Textron Canada Limited Model 429 helicopters.
Transport Canada advises that there have been reports of tail rotor gearbox assemblies found loose on the gearbox support. Transport Canada issued Emergency Canadian Airworthiness Directive CF201818, dated July 11, 2018, which corresponds to FAA AD
20181651, Amendment 3919421 83
FR 53171, October 22, 2018, to address the immediate safety concern. An ongoing investigation determined that this condition-loose tail rotor gearbox assemblies-could return even after the corrective actions by the previous AD
have been completed. This condition, if not addressed, could result in structural
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damage and possible loss of control of the helicopter.
Accordingly, Canadian AD CF2018
35 requires repetitive torque checks of the tail rotor gearbox attachment hardware and corrective actions if necessary. The corrective action is doing additional repetitive torque checks at intervals of 10 to 25 hours air time until the torque stabilizes on all the nuts.
Discussion of Final Airworthiness Directive Comments The FAA received no comments on the NPRM or on the determination of the costs.
Conclusion These helicopters have been approved by the aviation authority of Canada and are approved for operation in the United States. Pursuant to the FAAs bilateral agreement with Canada, Transport Canada, its technical representative, has notified the FAA of the unsafe condition described in its AD. The FAA reviewed the relevant data and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these helicopters. Except for minor editorial changes, this AD is adopted as proposed in the NPRM.
Related Service Information Under 1
CFR Part 51
The FAA reviewed Bell Alert Service Bulletin 4291841, dated July 24, 2018.
This service information specifies procedures for repetitive torque checks of the tail rotor gearbox attachment hardware.
This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.
Differences Between This AD and the Transport Canada AD
Where Canadian AD CF201835
refers to 200-hour inspections and 10 to 25 hours air time for the torque checks, for this AD use time-inservice instead.
Costs of Compliance The FAA estimates that this AD
affects 98 helicopters of U.S. Registry.
The FAA estimates the following costs to comply with this AD:

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