DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-1662; Project Identifier MCAI-2022-00689-T]
RIN 2120-AA64

Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain Bombardier, Inc., Model BD-100-1A10 airplanes. This
proposed AD was prompted by multiple reports of
erratic electrical system status on the push button annunciators (PBAs)
and the engine instrument and crew alerting system (EICAS) while on-
ground and during flight. This proposed AD would require a records
check and replacement of affected left-hand (LH) direct current power
center (DCPC) units. 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 February
27, 2023.

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-2022-1662; 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 service information identified in this
NPRM, 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 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.

FOR FURTHER INFORMATION CONTACT: Steven Dzierzynski, Aerospace
Engineer, Avionics & Electrical Systems Section, FAA, New York ACO
Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone
516-228-7367; 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-2022-1662; Project Identifier
MCAI-2022-00689-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, Aerospace Engineer, Avionics & Electrical Systems
Section, FAA, New York ACO Branch, 1600 Stewart Avenue, Suite 410,
Westbury, NY 11590; telephone 516-228-7367; 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-2022-28, dated June 9, 2022 (Transport
Canada AD CF-2022-28) (also referred to after this as the MCAI), to
correct an unsafe condition on certain Bombardier, Inc., Model BD-100-
1A10 airplanes. The MCAI states there have been multiple reports of
erratic electrical system status on the PBAs and the EICAS while on-
ground and during flight, and in several cases, leading to momentary
loss of electrical power and loss of flight displays following flight
crew responses to the erratic statuses. It was found that airplanes
could experience misleading electrical system status indications (PBA
and EICAS) as a result of contamination of electrical contacts in the
LH DCPC internal communication data bus. Those erratic indications
could cause the crew to turn off fully-operational electrical power
sources, leading to partial or complete loss of electrical power. Loss
of electrical power could result in the loss of flight displays and
reduced controllability of the airplane.
The MCAI also stated that Transport Canada previously issued CF-
2020-46, dated November 17, 2020 (which corresponds to FAA AD 2021-23-
14, Amendment 39-21812 (86 FR 68889, December 6, 2021)), which mandated
the use of revised Electrical Emergency and Non-Normal Procedures in
the airplane flight manual that directed crews not to turn off active
generators in the event of an erroneous electrical system status
indication. The MCAI advised that further corrective action is being
developed to introduce a design improvement to the DCPC that is
intended to protect the internal communication data bus from
contaminants, and that a time-limited maintenance check will also be
implemented.
You may examine the MCAI in the AD docket at regulations.gov under
Docket No. FAA-2022-1662.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Bombardier Service Bulletins 100-24-29 and 350-24-
004, both dated April 9, 2021. This service information specifies
procedures for a records check to determine the total flight hours and
replacement of affected LH DCPC units (part numbers 975GC02Y04,
975GC0Y05, 975GC02Y06, or 975GC02Y07). 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.

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,
it has notified the FAA of the unsafe condition described in the MCAI
and service information described 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 AD Requirements in This NPRM

This proposed AD would require accomplishing the actions specified
in the service information already described, except as discussed under
``Differences Between this NPRM and the MCAI or Service Information.''

Differences Between This NPRM and the MCAI or Service Information

The note to paragraph 2.B.(4) in Bombardier Service Bulletins 100-
24-29 and 350-24-004, both dated April 9, 2021, specifies to reset the
unit total flight hours to zero at date of incorporation. This proposed
AD would not require that action.

Interim Action

The FAA considers that this proposed AD would be an interim action.
The MCAI states that further corrective action is being developed. Once
this action is developed, approved, and available, the FAA might
consider additional rulemaking.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 315 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:

Estimated Costs for Required Actions

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 this on-condition action:

Estimated Costs of On-Condition Actions

The FAA has included all known costs in its cost estimate.
According to the manufacturer, however, some or all of the costs of
this proposed AD may be covered under warranty, thereby reducing the
cost impact on affected operators.

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: