Proposed Rule2026-17967
Airworthiness Directives; Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.) Airplanes
Primary source
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Published
September 2, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to supersede Airworthiness Directive (AD) 2021-17-07, which applies to certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. AD 2021-17-07 requires inspecting for damage of the left and right motive flow (MF) flexible fuel line assemblies (including the flexible hose and shroud assemblies), and replacing damaged parts. Since the FAA issued AD 2021- 17-07, the FAA has determined that four additional airplanes may be subject to the unsafe condition. This proposed AD would continue to require the actions in AD 2021-17-07 and expand the applicability. The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 91 Issue 169 (Wednesday, September 2, 2026)</title>
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[Federal Register Volume 91, Number 169 (Wednesday, September 2, 2026)]
[Proposed Rules]
[Pages 56377-56380]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-17967]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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Federal Register / Vol. 91, No. 169 / Wednesday, September 2, 2026 /
Proposed Rules
[[Page 56377]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2026-8794; Project Identifier MCAI-2025-01464-T]
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: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2021-17-07, which applies to certain Airbus Canada Limited Partnership
Model BD-500-1A10 and BD-500-1A11 airplanes. AD 2021-17-07 requires
inspecting for damage of the left and right motive flow (MF) flexible
fuel line assemblies (including the flexible hose and shroud
assemblies), and replacing damaged parts. Since the FAA issued AD 2021-
17-07, the FAA has determined that four additional airplanes may be
subject to the unsafe condition. This proposed AD would continue to
require the actions in AD 2021-17-07 and expand the applicability. 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 October 19,
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-2026-8794; 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:
<bullet> For Transport Canada material identified in this proposed
AD, contact Transport Canada, Transport Canada National Aircraft
Certification, 159 Cleopatra Drive, Nepean, Ontario K1A 0N5, Canada;
telephone 888-663-3639; email <a href="/cdn-cgi/l/email-protection#f6a2b5d8b79f84819984829e9f98938585b29f849395829f809385dbb59998859f9198938592939897809f9197949f9a9f8293d8a2b5b68295d89195d89597"><span class="__cf_email__" data-cfemail="f8acbbd6b9918a8f978a8c9091969d8b8bbc918a9d9b8c918e9d8bd5bb97968b919f969d8b9c9d96998e919f999a9194918c9dd6acbbb88c9bd69f9bd69b99">[email protected]</span></a>. You may find this material on the
Transport Canada website at tc.canada.ca/en/aviation. It is also
available at <a href="http://regulations.gov">regulations.gov</a> under Docket No. FAA-2026-8794.
<bullet> You may view this material at the FAA, Airworthiness
Products Section, Operational Safety Branch, 2200 South 216th St., Des
Moines, WA 98198. For information on the availability of this material
at the FAA, call 206-231-3195.
FOR FURTHER INFORMATION CONTACT: Anthony Decaro, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 562-
627-5374; email: <a href="/cdn-cgi/l/email-protection#6c0d02180403021542084208090f0d1e032c0a0d0d420b031a"><span class="__cf_email__" data-cfemail="a2c3ccd6cacdccdb8cc68cc6c7c1c3d0cde2c4c3c38cc5cdd4">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments using a method listed
under the ADDRESSES section. Include ``Docket No. FAA-2026-8794;
Project Identifier MCAI-2025-01464-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 this 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
<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 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
Anthony Decaro, Aviation Safety Engineer, FAA, 2200 South 216th St.,
Des Moines, WA 98198; phone: 562-627-5374; email:
<a href="/cdn-cgi/l/email-protection#1c7d72687473726532783278797f7d6e735c7a7d7d327b736a"><span class="__cf_email__" data-cfemail="ef8e819b87808196c18bc18b8a8c8e9d80af898e8ec1888099">[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
The FAA issued AD 2021-17-07, Amendment 39-21690 (86 FR 44600,
August 13, 2021) (AD 2021-17-07), for certain Airbus Canada Limited
Partnership Model BD-500-1A10 and BD-500-1A11 airplanes. AD 2021-17-07
was prompted by an MCAI originated by Transport Canada, which is the
aviation authority for Canada. Transport Canada issued AD CF-2021-09,
dated March 11, 2021 (Transport Canada AD CF-2021-09), to correct an
unsafe condition.
AD 2021-17-07 requires an inspection for damage of the right and
left MF flexible fuel hose assemblies (including the flexible hose and
shroud assemblies) and replacing damaged parts. The FAA issued AD 2021-
17-07
[[Page 56378]]
to address the potential of improper installation of the flexible hose
assembly of the fuel MF during production that may result in a twist to
the MF flexible fuel hose, which can restrict the flow of fuel for the
MF and cause fuel imbalance and possible damage, including abrasion, to
the shroud assembly. This condition, if not addressed, could result in
abrasion of the fuel line and a possible fuel leak; as a result, the
electrical harness connectors in the wing area could be a potential
ignition source and pose a risk of fire.
Actions Since AD 2021-17-07 Was Issued
Since the FAA issued 2021-17-07, Transport Canada superseded
Transport Canada AD CF-2021-09 and issued Transport Canada AD CF-2025-
47, dated September 11, 2025 (Transport Canada AD CF-2025-47) (also
referred to as the MCAI), to correct an unsafe condition for certain
Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11
airplanes. The MCAI states that since Transport Canada AD CF-2021-09
was issued, a new installation procedure was implemented by Airbus
Canada Limited Partnership in production, and it was discovered that
Transport Canada AD CF-2021-09 was not correctly implemented on four
additional Model BD-500-1A11 airplanes.
The FAA is proposing 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-2026-8794.
Explanation of Retained Requirements
Although this proposed AD does not explicitly restate the
requirements of AD 2021-17-07, this proposed AD would retain all of the
requirements of AD 2021-17-07. Those requirements are referenced in
Transport Canada AD CF-2025-47, which, in turn, is referenced in
paragraph (g) of this proposed AD.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Transport Canada AD CF-2025-47, which specifies
procedures for a general visual inspection for damage (including
permanent deformities) of the left and right MF fuel line assemblies
(including the flexible-hose assembly and shroud assembly), and
replacement of affected MF fuel line assemblies (including cleaning of
the ends of the flexible-hose assembly, injecting grease at both ends
of the flexible-hose assembly, and torquing the aft end of the
flexible-hose assembly).
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 the ADDRESSES section.
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 NPRM
after determining that the unsafe condition described previously is
likely to exist or develop in other products of the same type design.
Proposed AD Requirements in This NPRM
This proposed AD would require accomplishing the actions specified
in Transport Canada AD CF-2025-47 described previously, except for any
differences identified as exceptions in the regulatory text of this
proposed AD.
Explanation of Required Compliance Information
In the FAA's ongoing efforts to improve the efficiency of the AD
process, the FAA developed a process to use some civil aviation
authority (CAA) ADs as the primary source of information for compliance
with requirements for corresponding FAA ADs. The FAA has been
coordinating this process with manufacturers and CAAs. As a result, the
FAA proposes to retain the incorporation by reference (IBR) of
Transport Canada AD CF-2025-47 by reference in the FAA final rule. This
proposed AD would, therefore, require compliance with Transport Canada
AD CF-2025-47 in its entirety through that incorporation, except for
any differences identified as exceptions in the regulatory text of this
proposed AD. Material required by Transport Canada AD CF-2025-47 for
compliance will be available at <a href="http://regulations.gov">regulations.gov</a> under Docket No. FAA-
2026-8794 after the FAA final rule is published.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 13 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:
Estimated Costs for Required Actions
----------------------------------------------------------------------------------------------------------------
Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Retained actions from AD 2021-17-07 (9 10 work-hours x $85 per $0 $850 $7,650
airplanes). hour = $850.
New actions (4 airplanes)................ 10 work-hours x $85 per 0 850 3,400
hour = $850.
----------------------------------------------------------------------------------------------------------------
The FAA estimates the following costs to do any necessary on-
condition action 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 these on-condition actions:
Estimated Costs of On-Condition Actions
------------------------------------------------------------------------
Labor cost Parts cost Cost per product
------------------------------------------------------------------------
1 work-hour x $85 per hour = $9,920 per $10,005 per pylon.
$85 per pylon. pylon.
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According to the manufacturer, some or all of the costs of this
proposed AD may be covered under warranty, thereby reducing the cost
impact on affected individuals. The FAA does not control warranty
coverage for affected
[[Page 56379]]
individuals. As a result, the FAA has included all known costs in the
cost estimate.
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
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:
0
a. Removing Airworthiness Directive (AD) 2021-17-07, Amendment 39-21690
(86 FR 44600, August 13, 2021); and
0
b. Adding the following new AD:
Airbus Canada Limited Partnership (Type Certificate Previously Held
by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.)
Airplanes: Docket No. FAA-2026-8794; Project Identifier MCAI-2025-
01464-T.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by October 19, 2026.
(b) Affected ADs
This AD replaces AD 2021-17-07, Amendment 39-21690 (86 FR 44600,
August 13, 2021).
(c) Applicability
This AD applies to 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, as identified in Transport
Canada AD CF-2025-47, dated September 11, 2025 (Transport Canada AD
CF-2025-47).
(d) Subject
Air Transport Association (ATA) of America Code 28, Fuel.
(e) Unsafe Condition
This AD was prompted by the potential of improper installation
of the flexible hose assembly of the fuel motive flow (MF) during
production that may result in a twist to the MF flexible fuel hose,
which can restrict the flow of fuel for the MF and cause fuel
imbalance and possible damage, including abrasion, to the shroud
assembly. This AD was also prompted by a determination that
additional airplanes are subject to the unsafe condition. The FAA is
issuing this AD to address this condition. The unsafe condition, if
not addressed, could result in abrasion of the fuel line and a
possible fuel leak; as a result, the electrical harness connectors
in the wing area could be a potential ignition source and pose a
risk of fire.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Requirements
Except as specified in paragraphs (h) and (i) of this AD: Comply
with all required actions and compliance times specified in, and in
accordance with, Transport Canada AD CF-2025-47.
(h) Exceptions to Transport Canada AD CF-2025-47
(1) Where Transport Canada AD CF-2025-47 refers to its effective
date, this AD requires using the effective date of this AD.
(2) Where Transport Canada AD CF-2025-47 refers to March 25,
2021 (the effective date of Transport Canada AD CF-2021-09), this AD
requires using August 30, 2021 (the effective date of AD 2021-17-
07).
(3) Where Transport Canada AD CF-2025-47 specifies to ``if
necessary, replace the left and right motive flow fuel line
assemblies'', for this AD, replace that text with ``if any damage
(including any permanent deformity) is found on any motive flow
flexible fuel line assembly, replace the damaged assembly before
further flight''.
(i) No Return of Parts Requirement
Although the material referenced in Transport Canada AD CF-2025-
47 specifies to send removed parts to the manufacturer, this AD does
not include that requirement.
(j) 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 (k) of this AD and email to:
<a href="/cdn-cgi/l/email-protection#a0e1edefe3e0c6c1c18ec7cfd6"><span class="__cf_email__" data-cfemail="fdbcb0b2bebd9b9c9cd39a928b">[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.
(3) Required for Compliance (RC): Except as required by
paragraph (j)(2) of this AD, if any material contains procedures or
tests that are identified as RC, those procedures and tests must be
done to comply with this AD; any procedures or tests that are not
identified as RC are recommended. Those procedures and tests that
are not identified as RC may be deviated from using accepted methods
in accordance with the operator's maintenance or inspection program
without obtaining approval of an AMOC, provided the procedures and
tests identified as RC can be done and the airplane can be put back
in an airworthy condition. Any substitutions or changes to
procedures or tests identified as RC require approval of an AMOC.
(k) Additional Information
For more information about this AD, contact Anthony Decaro,
Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA
98198; phone: 562-627-5374; email: <a href="/cdn-cgi/l/email-protection#12737c667a7d7c6b3c763c76777173607d527473733c757d64"><span class="__cf_email__" data-cfemail="264748524e49485f0842084243454754496640474708414950">[email protected]</span></a>.
(l) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference of
[[Page 56380]]
the material listed in this paragraph under 5 U.S.C. 552(a) and 1
CFR part 51.
(2) You must use this material as applicable to do the actions
required by this AD, unless this AD specifies otherwise.
(i) Transport Canada AD CF-2025-47, dated September 11, 2025.
(ii) [Reserved]
(3) For Transport Canada material identified in this AD, contact
Transport Canada, Transport Canada National Aircraft Certification,
159 Cleopatra Drive, Nepean, Ontario K1A 0N5, Canada; telephone 888-
663-3639; email <a href="/cdn-cgi/l/email-protection#edb9aec3ac849f9a829f99858483889e9ea9849f888e99849b889ec0ae82839e848a83889e8988838c9b848a8c8f8481849988c3b9aead998ec38a8ec38e8c"><span class="__cf_email__" data-cfemail="3b6f78157a52494c54494f5352555e48487f52495e584f524d5e481678545548525c555e485f5e555a4d525c5a595257524f5e156f787b4f58155c5815585a">[email protected]</span></a>. You may find this material on
the Transport Canada website at tc.canada.ca/en/aviation.
(4) You may view this material at the FAA, Airworthiness
Products Section, Operational Safety Branch, 2200 South 216th St.,
Des Moines, WA 98198. For information on the availability of this
material at the FAA, call 206-231-3195.
(5) You may view this material at the National Archives and
Records Administration (NARA). For information on the availability
of this material at NARA, visit <a href="http://www.archives.gov/federal-register/cfr/ibr-locations">www.archives.gov/federal-register/cfr/ibr-locations</a> or email <a href="/cdn-cgi/l/email-protection#d4b2a6fabdbaa7a4b1b7a0bdbbba94bab5a6b5fab3bba2"><span class="__cf_email__" data-cfemail="6b0d19450205181b0e081f0204052b050a190a450c041d">[email protected]</span></a>.
Issued on August 31, 2026.
Brian Knaup,
Acting Deputy Director, Integrated Certificate Management Division,
Aircraft Certification Service.
[FR Doc. 2026-17967 Filed 9-1-26; 8:45 am]
BILLING CODE 4910-13-P
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