DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0784; Project Identifier MCAI-2020-01455-T;
Amendment 39-21857; AD 2021-25-13]
RIN 2120-AA64

Airworthiness Directives; Bombardier, Inc. Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain Bombardier, Inc., Model CL-600-1A11 (600), CL-600-2A12 (601),
and CL-600-2B16 (601-3A, 601-3R, and 604 Variants) airplanes. This AD
was prompted by a determination that new or more restrictive
airworthiness limitations are necessary. This AD requires revising the
existing maintenance or inspection program, as applicable, to
incorporate new or more restrictive airworthiness limitations. 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,
2022.

ADDRESSES: For service information identified in this final rule,
contact Bombardier Business Aircraft Customer Response Center, 400
Cote Vertu Road West, Dorval, Quebec H4S 1Y9, Canada; 514-
855-2999; email ac.yul@aero.bombardier.com; 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-2021-0784.

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-
0784; 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 9-avs-nyaco-cos@faa.gov.

SUPPLEMENTARY INFORMATION:

Background

Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued TCCA AD CF-2020-44, dated October 23,
2020 (referred to after this as the Mandatory Continuing Airworthiness
Information, or the MCAI), to correct an unsafe condition for certain
Bombardier, Inc., Model CL-600-1A11 (600), CL-600-2A12 (601), and CL-
600-2B16 (601-3A, 601-3R, and 604 Variants) 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-2021-0784.
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 CL-600-1A11 (600), CL-600-2A12 (601), and CL-600-2B16 (601-
3A, 601-3R, and 604 Variants) airplanes. The NPRM published in the
Federal Register on September 14, 2021 (86 FR 51029). The NPRM was
prompted by a determination that new or more restrictive airworthiness
limitations are necessary. The NPRM proposed to require revising the
existing maintenance or inspection program, as applicable, to
incorporate new or more restrictive airworthiness limitations. The FAA
is issuing this AD to address fatigue cracking and loss of structural
integrity of the circumferential splice joint, which could result in
reduced structural integrity of the airplane. See the MCAI for
additional background information.

Comments

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.

Conclusion

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
minor changes:
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

The FAA reviewed the following Bombardier service information,
which describes new or more restrictive airworthiness limitations (a
special detailed inspection for cracking of the skin circumferential
splice at fuselage station (FS) 559.00, between stringer (STR) 10L and
STR10R). Note: The asterisk (or ``one star'') with the last three
digits of the task number indicates that the task is an airworthiness
limitation task.
Bombardier Challenger 600 Time Limits/Maintenance Checks
(TLMC), Product Support Publication (PSP) 605, Temporary Revision (TR)
5-163, dated April 30, 2020, which includes Task 53-30-00-165*, ``Skin
Circumferential Splice at FS559.00, between STR10L and STR10R.''
Bombardier Challenger 601 TLMC, PSP 601-5, TR 5-267, dated
April 30, 2020, which includes Task 53-30-00-188*, ``Skin
Circumferential Splice at FS559.00, between STR10L and STR10R.''
Bombardier Challenger 601 TLMC, PSP 601A-5, TR 5-281,
dated April 30, 2020, which includes Task 53-30-00-191*, ``Skin
Circumferential Splice at FS559.00, between STR10L and STR10R.''
Section 5-10-30, Airworthiness Limitation Items,
Bombardier Challenger 604 TLMC, Publication No. CH 604 TLMC, Part 2,
Revision 32, dated December 18, 2019, which includes Task 53-20-00-
192*, ``Special Detailed Inspection of the Skin
Circumferential Splice at FS559.00, between Stringers10L and 10R.''
Section 5-10-30, Airworthiness Limitation Items,
Bombardier Challenger 605 TLMC, Publication No. CH 605 TLMC, Part 2,
Revision 21, dated December 18, 2019, which includes Task 53-20-00-
192*, ``Special Detailed Inspection of the Skin Circumferential Splice
at FS559.00, between Stringers10L and 10R.''
Section 5-10-30, Airworthiness Limitation Items,
Bombardier Challenger 650 TLMC, Publication No. CH 650 TLMC, Part 2,
Revision 8, dated December 18, 2019, which includes Task 53-20-00-192*,
``Special Detailed Inspection of the Skin Circumferential Splice at
FS559.00, between Stringers10L and 10R.''
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 463 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:
The FAA has determined that revising the existing maintenance or
inspection program takes an average of 90 work-hours per operator,
although the agency recognizes that this number may vary from operator
to operator. Since operators incorporate maintenance or inspection
program changes for their affected fleet(s), the FAA has determined
that a per-operator estimate is more accurate than a per-airplane
estimate. Therefore, the agency estimates the average total cost per
operator to be $7,650 (90 work-hours x $85 per work-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.

Regulatory Findings

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
Order 12866,
(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
reference, Safety.

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
directive: