DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0513; Project Identifier 2018-SW-116-AD; Amendment
39-21717; AD 2021-18-16]
Airworthiness Directives; Bell Textron Canada Limited (Type
Certificate Previously Held by Bell Helicopter Textron Canada Limited)
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
SUMMARY: The FAA is adopting a new airworthiness directive (AD)
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,
ADDRESSES: For service information identified in this final rule,
contact Bell Textron Canada Limited, 12,800 Rue de l'Avenir, Mirabel,
Quebec J7J 1R4, Canada; telephone 1-450-437-2862 or 1-800-363-8023; fax
1-450-433-0272; email email@example.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 6N-321, Fort Worth, TX
76177. For information on the availability of this material at the FAA,
call 817-222-5110. It is also available at https://www.regulations.gov
by searching for and locating Docket No. FAA-2021-0513.
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0513; 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 W12-140, 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) 228-7323; email
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 CF-2018-35, dated December 19, 2018 (Canadian
AD CF-2018-35), 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 CF-2018-18, dated July 11, 2018, which
corresponds to FAA AD 2018-16-51, Amendment 39-19421 (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 damage and possible loss of control of the
Accordingly, Canadian AD CF-2018-35 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
The FAA received no comments on the NPRM or on the determination of
These helicopters have been approved by the aviation authority of
Canada and are approved for operation in the United States. Pursuant to
the FAA's 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 429-18-41, 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 CF-2018-35 refers to ``200-hour'' inspections and
``10 to 25 hours air time'' for the torque checks, for this AD use
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:
Estimated Costs for Required Actions
||1 work-hour x $85 per hour =
The FAA estimates the following costs
to do any necessary on-
condition actions that are required based on the results of any
required actions. The FAA has no way of determining the number of
helicopters that might need these on-condition actions:
Estimated Costs of On-Condition Actions
|Repetitive torque check
||1 work-hour x $85 per hour =
$85, per cycle
$85, per cycle
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. Subtitle VII: Aviation Programs,
describes in more detail the scope of the Agency's authority.
The FAA is issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701: General requirements.
Under that section, Congress charges the FAA with promoting safe flight
of civil aircraft in air commerce by prescribing regulations for
practices, methods, and procedures the Administrator finds necessary
for safety in air commerce. This regulation is within the scope of that
authority because it addresses an unsafe condition that is likely to
exist or develop on helicopters identified in this rulemaking action.
This AD will not have federalism implications under Executive Order
13132. This AD will not have a substantial direct effect on the States,
on the relationship between the national government and the States, or
on the distribution of power and responsibilities among the various
levels of government.
For the reasons discussed above, I certify that this AD:
(1) Is not a ``significant regulatory action'' under Executive
(2) Will not affect intrastate aviation in Alaska, and
(3) Will not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. The FAA amends Sec. 39.13 by adding the following new airworthiness