DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2007; Project Identifier MCAI-2023-01270-T]
RIN 2120-AA64

Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

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

DATES: The FAA must receive comments on this proposed AD by September
23, 2024.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to regulations.gov. Follow
the instructions for submitting comments.
Fax: 202-493-2251.
Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.
Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
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 NPRM, the mandatory continuing airworthiness
information (MCAI), any comments received, and other information. The
street address for Docket Operations is listed above.
Material Incorporated by Reference:
For Bombardier, Inc. material identified in this proposed
AD, contact Bombardier Business Aircraft Customer Response Center, 400
Cote Vertu Road West, Dorval, Quebec H4S 1Y9, Canada;
telephone 514-855-2999; email 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 Street,
Des Moines, WA. For information on the availability of this material at
the FAA, call 206-231-3195.

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:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include ``Docket No. FAA-2024-2007; Project Identifier
MCAI-2023-01270-T'' at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend
the proposal because of those comments.
Except for Confidential Business Information (CBI) as described in
the following paragraph, and other
information as described in 14 CFR 11.35, the FAA will post all
comments received, without change, to regulations.gov, including any
personal information you provide. The agency will also post a report
summarizing each substantive verbal contact received about this NPRM.

Confidential Business Information

CBI is commercial or financial information that is both customarily
and actually treated as private by its owner. Under the Freedom of
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public
disclosure. If your comments responsive to this NPRM contain commercial
or financial information that is customarily treated as private, that
you actually treat as private, and that is relevant or responsive to
this NPRM, it is important that you clearly designate the submitted
comments as CBI. Please mark each page of your submission containing
CBI as ``PROPIN.'' The FAA will treat such marked submissions as
confidential under the FOIA, and they will not be placed in the public
docket of this NPRM. Submissions containing CBI should be sent to
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. Any commentary that the FAA receives which is not
specifically designated as CBI will be placed in the public docket for
this rulemaking.

Background

Transport Canada, which is the aviation authority for Canada, has
issued Transport Canada AD CF-2023-78, dated December 19, 2023
(Transport Canada AD CF-2023-78) (also referred to as the MCAI), to
correct an unsafe condition for all Bombardier, Inc., Model BD-100-1A10
airplanes. The MCAI states that airplanes could experience misleading
electrical system status indications (push button annunciators (PBA)
and engine indicating 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 AD's.
The FAA is proposing 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.

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 BD-100 Time Limits/Maintenance Checks,
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 BD-100 Time Limits/Maintenance Checks,
Revision 14, dated August 9, 2023.
This material specifies new or more restrictive airworthiness
limitations for safe life limits.
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.

FAA's Determination

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, the
FAA has been notified of the unsafe condition described in the MCAI and
material referenced above. The FAA is issuing this NPRM after
determining that the unsafe condition described previously is likely to
exist or develop on other products of the same type design.

Proposed Requirements of This NPRM

This proposed AD would require revising the existing maintenance or
inspection program, as applicable, to incorporate new or more
restrictive maintenance tasks.
This proposed AD would require revisions to certain operator
maintenance documents to include new actions (e.g., inspections).
Compliance with these actions is required by 14 CFR 91.403(c). For
airplanes that have been previously modified, altered, or repaired in
the areas addressed by this proposed AD, the operator may not be able
to accomplish the actions described in the revisions. In this
situation, to comply with 14 CFR 91.403(c), the operator must request
approval for an alternative method of compliance according to paragraph
(i)(1) of this proposed AD.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 356 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed 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

The FAA determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 this proposed
regulation:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866,
(2) Would not affect intrastate aviation in Alaska, and
(3) Would 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 Proposed Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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: