Rule2026-06465
Airworthiness Directives; Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.) Airplanes
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
April 2, 2026
Effective
April 17, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is adopting a new airworthiness directive (AD) for all Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. This AD was prompted by the discovery that the outflow valve (OFV) direct current (DC) motor could potentially be inoperative when used in high differential pressure conditions. This AD prohibits dispatching an airplane under certain master minimum equipment list (MMEL) items and prohibits dispatching if a certain crew alerting system (CAS) message is displayed. The FAA is issuing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 91 Issue 63 (Thursday, April 2, 2026)</title>
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[Federal Register Volume 91, Number 63 (Thursday, April 2, 2026)]
[Rules and Regulations]
[Pages 16546-16548]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-06465]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2026-3470; Project Identifier MCAI-2026-00210-T;
Amendment 39-23302; AD 2026-07-07]
RIN 2120-AA64
Airworthiness Directives; Airbus Canada Limited Partnership (Type
Certificate Previously Held by C Series Aircraft Limited Partnership
(CSALP); Bombardier, Inc.) Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule; request for comments.
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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11
airplanes. This AD was prompted by the discovery that the outflow valve
(OFV) direct current (DC) motor could potentially be inoperative when
used in high differential pressure conditions. This AD prohibits
dispatching an airplane under certain master minimum equipment list
(MMEL) items and prohibits dispatching if a certain crew alerting
system (CAS) message is displayed. The FAA is issuing this AD to
address the unsafe condition on these products.
DATES: This AD is effective April 17, 2026.
The FAA must receive comments on this AD by May 18, 2026.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="http://regulations.gov">regulations.gov</a>. Follow
the instructions for submitting comments.
<bullet> Fax: 202-493-2251.
<bullet> 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.
<bullet> 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 <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2026-3470; 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
street address for Docket Operations is listed above.
FOR FURTHER INFORMATION CONTACT: Joshua Baek, Aviation Safety Engineer,
FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 562-627-6725;
email: <a href="/cdn-cgi/l/email-protection#e08a8f93889581ce99ce8281858ba0868181ce878f96"><span class="__cf_email__" data-cfemail="117b7e627964703f683f7370747a517770703f767e67">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written data, views, or arguments
about this final rule. Send your comments using a method listed under
the ADDRESSES section. Include ``Docket No. FAA-2026-3470; Project
Identifier MCAI-2026-00210-T'' at the beginning of your comments. The
most helpful comments reference a specific portion of the final rule,
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 this final rule 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
<a href="http://regulations.gov">regulations.gov</a>, including any personal information you provide. The
agency will also post a report summarizing each substantive verbal
contact received about this final rule.
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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to Joshua
Baek, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines,
WA 98198; phone: 562-627-6725; email: <a href="/cdn-cgi/l/email-protection#7a101509120f1b540354181b1f113a1c1b1b541d150c"><span class="__cf_email__" data-cfemail="6802071b001d094611460a090d03280e0909460f071e">[email protected]</span></a>. 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-2026-10, dated February 27, 2026
(Transport Canada AD CF-2026-10) (also referred to as the MCAI), to
correct an unsafe condition for all Airbus Canada Limited Partnership
Model BD-500-1A10 and BD-500-1A11 airplanes. The MCAI states that it
was discovered during production flight tests that the OFV DC motor
could potentially be inoperative when used in high differential
pressure conditions. The cabin pressure control system (CPCS)
automatically controls the pressure inside the cabin by controlling the
flow of pressurized air through the OFV. The OFV normally operates in
automatic (AUTO) mode and uses two separate OFV stepper motors during
all phases of flight. The OFV can also operate in manual (MAN) mode and
use the OFV DC motor under certain condition. The high differential
pressure across the OFV can increase the friction between the OFV
butterfly shaft and the OFV body, resulting in excessive torque being
required to operate the OFV. This excessive torque may trip the OFV MAN
mode torque limiter resulting in loss of OFV control in CPCS MAN mode.
This condition, if not corrected, could potentially lead to total loss
of cabin pressure control, excessive differential pressure across the
airplane structure, inability to rapidly depressurize the airplane to
ambient, when needed, and inability to evacuate smoke, when needed.
The FAA is issuing this AD to address the unsafe condition on these
products.
You may examine the MCAI in the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2026-3470.
FAA's Determination
These products have been approved by the civil aviation authority
of another country and are approved for operation in the United States.
Pursuant to the FAA's bilateral agreement with this State of Design
Authority, that authority has notified the FAA of the unsafe condition
described in the MCAI referenced above. The FAA is issuing this AD
after determining that the unsafe condition described previously is
[[Page 16547]]
likely to exist or develop on other products of the same type design.
AD Requirements
This AD prohibits dispatching an airplane under certain dispatch
provisions within Master Minimum Equipment List (MMEL) items 21-33-03
and 21-33-04 and prohibits dispatch if a certain CAS message is
displayed.
The FAA notes there are two operational procedures (O) within MMEL
items 21-33-03 and 21-33-04. For this AD, only the operational
procedures listed in figure 1 to paragraph (g)(2) of this AD are
prohibited.
Interim Action
The FAA considers that this AD is an interim action. If final
action is later identified, the FAA might consider further rulemaking
then.
Justification for Immediate Adoption and Determination of the Effective
Date
Section 553(b) of the Administrative Procedure Act (APA) (5 U.S.C.
551 et seq.) authorizes agencies to dispense with notice and comment
procedures for rules when the agency, for ``good cause,'' finds that
those procedures are ``impracticable, unnecessary, or contrary to the
public interest.'' Under this section, an agency, upon finding good
cause, may issue a final rule without providing notice and seeking
comment prior to issuance. Further, section 553(d) of the APA
authorizes agencies to make rules effective in less than thirty days,
upon a finding of good cause.
An unsafe condition exists that requires the immediate adoption of
this AD without providing an opportunity for public comments prior to
adoption. The FAA has found that the risk to the flying public
justifies forgoing notice and comment prior to adoption of this rule
because the OFV DC motor could potentially be inoperative when used in
high differential pressure conditions. The high differential pressure
across the OFV can increase the friction between the OFV butterfly
shaft and the OFV body, resulting in excessive torque being required to
operate the OFV. This excessive torque may trip the OFV MAN mode torque
limiter resulting in loss of OFV control in CPCS MAN mode. This
condition, if not corrected, could potentially lead to total loss of
cabin pressure control, excessive differential pressure across the
airplane structure, inability to rapidly depressurize the airplane to
ambient, when needed, and inability to evacuate smoke, when needed.
Additionally, the compliance time in this AD is shorter than the time
necessary for the public to comment and for publication of the final
rule. Accordingly, notice and opportunity for prior public comment are
impracticable and contrary to the public interest pursuant to 5 U.S.C.
553(b).
In addition, the FAA finds that good cause exists pursuant to 5
U.S.C. 553(d) for making this amendment effective in less than 30 days,
for the same reasons the FAA found good cause to forgo notice and
comment.
Regulatory Flexibility Act
The requirements of the Regulatory Flexibility Act (RFA) do not
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt
a rule without prior notice and comment. Because the FAA has determined
that it has good cause to adopt this rule without notice and comment,
RFA analysis is not required.
Costs of Compliance
The FAA estimates that this AD affects 198 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:
Estimated Costs for Required Actions
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Cost per Cost on U.S.
Labor cost Parts cost product operators
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1 work-hour x $85 per hour = $85............................. $0 $85 $16,830
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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, and
(2) Will not affect intrastate aviation in Alaska.
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
0
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]
0
2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive:
2026-07-07 Airbus Canada Limited Partnership (Type Certificate
Previously Held by C Series Aircraft Limited Partnership (CSALP);
Bombardier, Inc.): Amendment 39-23302; Docket No. FAA-2026-3470;
Project Identifier MCAI-2026-00210-T.
(a) Effective Date
This airworthiness directive (AD) is effective April 17, 2026.
(b) Affected ADs
None.
[[Page 16548]]
(c) Applicability
This AD applies to all Airbus Canada Limited Partnership (Type
Certificate previously held by C Series Aircraft Limited Partnership
(CSALP); Bombardier, Inc.) Model BD-500-1A10 and BD-500-1A11
airplanes, certificated in any category.
(d) Subject
Air Transport Association (ATA) of America Code 21, Air
conditioning system.
(e) Unsafe Condition
This AD was prompted by the discovery during production flight
tests that the outflow valve (OFV) direct current (DC) motor could
potentially be inoperative when used in high differential pressure
conditions. The FAA is issuing this AD to address loss of OFV
control in cabin pressure control system (CPCS) manual (MAN) mode,
which if not corrected, could potentially lead to total loss of
cabin pressure control, excessive differential pressure across the
airplane structure, inability to rapidly depressurize the airplane
to ambient, when needed, and inability to evacuate smoke, when
needed.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Dispatch Prohibitions
(1) As of the effective date of this AD, no person may dispatch
an airplane if crew alerting system (CAS) message ``AUTO PRESS FAIL
(CAUTION)'' is displayed.
(2) As of the effective date of this AD, no person may dispatch
an airplane under the operational procedures of the operator's
minimum equipment list (MEL) items corresponding with the following
operational procedures of the Master Minimum Equipment List (MMEL)
items listed in figure 1 to paragraph (g)(2) of this AD.
Note 1 to paragraph (g)(2): There are two operational procedures
(O) within MMEL items 21-33-03 and 21-33-04. For this AD, only
dispatch under the operational procedures listed in figure 1 to
paragraph (g)(2) of this AD is prohibited.
Figure 1 to Paragraph (g)(2)--Prohibited MMEL Items
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21. Air Conditioning....................................................
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Sequence No. Item............. Description
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33-03......................... Landing Field (O) May be
Elevation (LFE) inoperative
Indication. provided:
(a) Pressurization is
operated in manual
control mode,
(b) Autopilot is
operative,
(c) Minimum enroute
altitude does not
exceed 10,000 ft.
above MSL, and
(d) Operations are
restricted to
airports at or below
8,000 ft. Landing
Field Elevation
(LFE).
33-04......................... Landing Field (O) May be
Elevation (LFE) inoperative
Automatic provided:
Selection. (a) Pressurization is
conducted in manual
mode,
(b) Autopilot is
operative, and
(c) Operations are
restricted to
airports at or below
8,000 ft. Landing
Field Elevation
(LFE).
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(h) Additional AD Provisions
The following provisions also apply to this AD:
(1) Alternative Methods of Compliance (AMOCs): The Manager, AIR-
520, Continued Operational Safety Branch, FAA, has the authority to
approve AMOCs for this AD, if requested using the procedures found
in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request
to your principal inspector or responsible Flight Standards Office,
as appropriate. If sending information directly to the manager of
the Continued Operational Safety Branch, send it to the attention of
the person identified in paragraph (i) of this AD and email to:
<a href="/cdn-cgi/l/email-protection#92d3dfddd1d2f4f3f3bcf5fde4"><span class="__cf_email__" data-cfemail="4b0a0604080b2d2a2a652c243d">[email protected]</span></a>. Before using any approved AMOC, notify your
appropriate principal inspector, or lacking a principal inspector,
the manager of the responsible Flight Standards Office.
(2) Contacting the Manufacturer: For any requirement in this AD
to obtain instructions from a manufacturer, the instructions must be
accomplished using a method approved by the Manager, AIR-520,
Continued Operational Safety Branch, FAA; or Transport Canada; or
Airbus Canada Limited Partnership's Transport Canada Design Approval
Organization (DAO). If approved by the DAO, the approval must
include the DAO-authorized signature.
(i) Additional Information
For more information about this AD, contact Joshua Baek,
Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA
98198; phone: 562-627-6725; email: <a href="/cdn-cgi/l/email-protection#fc96938f94899dd285d29e9d9997bc9a9d9dd29b938a"><span class="__cf_email__" data-cfemail="e983869a819c88c790c78b888c82a98f8888c78e869f">[email protected]</span></a>.
(j) Material Incorporated by Reference
None.
Issued on March 31, 2026.
Victor Wicklund,
Acting Director, Integrated Certificate Management Division, Aircraft
Certification Service.
[FR Doc. 2026-06465 Filed 3-31-26; 4:15 pm]
BILLING CODE 4910-13-P
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