DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0658; Project Identifier MCAI-2020-01582-T;
Amendment 39-21850; AD 2021-25-07]
Airworthiness Directives; Bombardier, Inc., Airplanes
AGENCY: Federal Aviation Administration (FAA), Department of
ACTION: Final rule.
SUMMARY: The FAA is adopting a new airworthiness directive (AD)
certain Bombardier, Inc., Model BD-100-1A10 airplanes. This AD was
prompted by a discovery that a lockwire may not have been installed on
the side stay actuator pin nut of the main landing gear (MLG). This AD
requires inspecting the left-hand and right-hand MLG side stay actuator
assembly pin nut for the presence of a lockwire, and installing a
lockwire if necessary. The FAA is issuing this AD to address the unsafe
condition on these products.
DATES: This AD is effective February 15, 2022.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of February 15,
ADDRESSES: For service information identified in this final rule,
contact Bombardier, Inc., 200 Cote-Vertu Road West, Dorval,
Quebec H4S 2A3, Canada; North America toll-free telephone 1-866-
538-1247 or direct-dial telephone 1-514-855-2999; email
firstname.lastname@example.org; internet https://www.bombardier.com. You
may view this service information at the FAA, Airworthiness Products
Section, Operational Safety Branch, 2200 South 216th St., Des Moines,
WA. For information on the availability of this material at the FAA,
call 206-231-3195. It is also available on the internet at https://www.
regulations.gov by searching for and locating Docket No. FAA-2021-
Examining the AD Docket
You may examine the AD docket on the internet at https://www.regulations.
gov by searching for and locating Docket No. FAA-2021-
0658; 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, any comments received, and other information. The
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: Elizabeth Dowling, Aerospace Engineer,
Mechanical Systems and Administrative Services Section, FAA, New York
ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
telephone 516-228-7300; fax 516-794-5531; email email@example.com.
Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued TCCA AD CF-2020-52, dated November 30,
2020 (also referred to after this as the Mandatory Continuing
Airworthiness Information, or the MCAI), to correct an unsafe condition
for certain Bombardier, Inc., Model BD-100-1A10 airplanes. You may
examine the MCAI in the AD docket on the internet at https://www.regulations.gov
by searching for and locating Docket No. FAA-2021-0658.
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to certain Bombardier,
Inc., Model BD-100-1A10 airplanes. The NPRM published in the Federal
Register on August 12, 2021 (86 FR 44314). The NPRM was prompted by a
discovery that a lockwire may not have been installed on the side stay
actuator pin nut of the MLG. The NPRM proposed to require inspecting
the left-hand and right-hand MLG side stay actuator assembly pin nut
for the presence of a lockwire, and installing a lockwire if necessary.
The FAA is issuing this AD to address a possible missing lockwire,
which could result in loss of the nut, and if undetected, lead to the
collapse of the affected MLG. See the MCAI for additional background
The FAA gave the public the opportunity to participate in
developing this final rule. The FAA received no comments on the NPRM or
on the determination of the cost to the public.
The FAA reviewed the relevant data and determined that air safety
and the public interest require adopting this final rule as proposed,
except for minor editorial changes. The FAA has determined that these
Are consistent with the intent that was proposed in the
NPRM for addressing the unsafe condition; and
Do not add any additional burden upon the public than was
already proposed in the NPRM.
Related Service Information Under 1 CFR Part 51
Bombardier has issued Service Bulletin 100-32-36, dated June 25,
2020; and Service Bulletin 350-32-012, dated June 25, 2020. This
service information describes procedures for inspecting the left-hand
and right-hand MLG side stay actuator assembly pin nut for presence of
a lockwire and installing a lockwire. These documents
are distinct since they apply to different airplane configurations.
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.
Costs of Compliance
The FAA estimates that this AD affects 623 airplanes 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 would be required based on the results of any
required actions. The FAA has no way of determining the number of
aircraft that might need these on-condition actions:
Estimated Costs of On-Condition Actions
|1 work-hour x $85 per hour =
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 products 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
Adoption of the Amendment
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