Airworthiness Directives; Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.) Airplanes

[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 [www.gpo.gov]
[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 regulations.gov. 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 regulations.gov 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: [email protected].

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 
regulations.gov, 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: [email protected]. 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 regulations.gov 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
----------------------------------------------------------------------------------------------------------------
                                                                                    Cost per       Cost on U.S.
                          Labor cost                              Parts cost        product         operators
----------------------------------------------------------------------------------------------------------------
1 work-hour x $85 per hour = $85.............................              $0              $85          $16,830
----------------------------------------------------------------------------------------------------------------

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

------------------------------------------------------------------------
 
------------------------------------------------------------------------
21. Air Conditioning....................................................
------------------------------------------------------------------------
Sequence No.                    Item.............  Description
------------------------------------------------------------------------
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).
------------------------------------------------------------------------

 (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: 
[email protected]. 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: [email protected].

 (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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