DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2007; Project Identifier MCAI-2023-01270-T;
Amendment 39-22871; AD 2024-21-04]
RIN 2120-AA64

Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
Bombardier, Inc., Model BD-100-1A10 airplanes. This AD was prompted by
a determination that new or more restrictive maintenance tasks are
necessary. This AD requires revising the existing maintenance or
inspection program, as applicable, to incorporate new or more
restrictive maintenance tasks. The FAA is issuing this AD to address
the unsafe condition on these products.

DATES: This AD is effective December 17, 2024.

The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of December 17, 2024.

ADDRESSES:

AD Docket: You may examine the AD docket at regulations.gov under
Docket No. FAA-2024-2007; 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 mandatory continuing airworthiness
information (MCAI), 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.

Material Incorporated by Reference:

For Bombardier, Inc. material identified in this AD,
contact Bombardier Business Aircraft Customer Response Center, 400
Cote Vertu Road West, Dorval, Quebec H4S 1Y9, Canada;
telephone 514-855-2999; email bombardier.com">ac.yul@aero.bombardier.com; website
bombardier.com.

You may view this material 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 at regulations.gov under
Docket No. FAA-2024-2007.

FOR FURTHER INFORMATION CONTACT: Steven Dzierzynski, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
telephone: 516-228-7300; email: 9-avs-nyaco-cos@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 all Bombardier, Inc.,
Model BD-100-1A10 airplanes. The NPRM published in the Federal Register
on August 9, 2024 (89 FR 65267). The NPRM was prompted by AD CF-2023-
78, dated December 19, 2023, issued by Transport Canada, which is the
aviation authority for Canada (also referred to as the MCAI). The MCAI
states that airplanes could experience misleading electrical system
status indications (push button annunciators (PBA) and engine
instrument and crew alerting system (EICAS)) as a result of
contamination of electrical contacts in the left-hand (LH) direct
current power center (DCPC) internal communication data bus. The MCAI
states that new or more restrictive maintenance tasks have been
developed to rectify lower time LH DCPC units not addressed by
previously issued ADs.

In the NPRM, the FAA proposed to require revising the existing
maintenance or inspection program, as applicable, to incorporate new or
more restrictive maintenance tasks. The FAA is issuing this AD to
address erratic indications, which could cause the flightcrew to turn
off fully operational electrical power sources, leading to partial or
complete loss of electrical power. The unsafe condition, if not
addressed, could result in loss of flight displays and reduced
controllability of the airplane.

You may examine the MCAI in the AD docket at regulations.gov under
Docket No. FAA-2024-2007.

Discussion of Final Airworthiness Directive

Comments

The FAA received no comments on the NPRM or on the determination of
the cost to the public.

Conclusion

This product has been approved by the aviation authority of another
country and is approved for operation in the United States. Pursuant to
the FAA's bilateral agreement with this State of Design Authority, it
has notified the FAA of the unsafe condition described in the MCAI
referenced above. 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 this product.
Except for minor editorial changes, this AD is adopted as proposed in
the NPRM. None of the changes will increase the economic burden on any
operator.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed the following documents:

Task 24-61-01-101*, "Restoration of the left DC Power
Center (DCPC) (Pre SB100-24-30)," Section 5-10-20, "Time Limits--
Supplementary Limitations," of Part 2, "Airworthiness Limitations",
of the Bombardier Challenger 300 Time Limits/Maintenance Checks,
Publication No. CH 300 TLMC, Revision 24, dated August 9, 2023.

Task 24-61-01-101*, "Restoration of the Left DC Power
Center (DCPC) (Pre SB350-24-005)," Section 5-10-20, "Time Limits--
Supplementary Limitations," of Part 2, "Airworthiness Limitations,"
of the Bombardier Challenger 350 Time Limits/Maintenance Checks,
Publication No. CH 350 TLMC, Revision 14, dated August 9, 2023.

This material specifies new or more restrictive airworthiness
limitations for safe life limits. These documents are distinct since they apply to
different airplane configurations. The asterisk (or "one star") with
the last three digits of the task numbers indicates that the task is an
airworthiness limitation task.

This material is reasonably available because the interested
parties have access to it through their normal course of business or by
the means identified in ADDRESSES section.

Costs of Compliance

The FAA estimates that this AD affects 356 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD.

The FAA has determined that revising the 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.

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: