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 145 (Thursday, July 30, 2026)]
[Rules and Regulations]
[Pages 47951-47953]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-15411]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2026-1336; Project Identifier MCAI-2025-00254-T; 
Amendment 39-23426; AD 2026-15-14]
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.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2025-06-
01, which applied to all Airbus Canada Limited Partnership Model BD-
500-1A10 and BD-500-1A11 airplanes. AD 2025-06-01 required revising the 
existing airplane flight manual (AFM) to incorporate the procedures for 
the flightcrew to manually isolate the opposite functional engine in 
the event of an engine bleed duct large leak condition. Since the FAA 
issued AD 2025-06-01, an electronic engine control (EEC) software 
update has been developed to address the unsafe condition. This AD 
continues to require the actions in AD 2025-06-01 and requires 
installing a certain EEC software update on both engines. This AD also 
removes airplanes from the applicability. The FAA is issuing this AD to 
address the unsafe condition on these products.

DATES: This AD is effective September 3, 2026.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of September 3, 
2026.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2026-1336; 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 
address for Docket Operations is U.S. Department of Transportation, 
Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 
New Jersey Avenue SE, Washington, DC 20590.
    Material Incorporated by Reference:
    <bullet> 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 [email protected]. You may find this material on the 
Transport Canada website at tc.canada.ca/en/aviation.
    <bullet> You may view this material 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. It is also available at regulations.gov under 
Docket No. FAA-2026-1336.

FOR FURTHER INFORMATION CONTACT: Erica Bayles, Aviation Safety 
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 907-
271-5844; email: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to supersede AD 2025-06-01, Amendment 39-22989 (90 FR 
12457, March 18, 2025) (AD 2025-06-01). AD 2025-06-01 applied to all 
Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500-1A11 
airplanes. AD 2025-06-01 required revising the existing AFM to 
incorporate the procedures for the flightcrew to manually isolate the 
opposite functional engine in the event of an engine bleed duct large 
leak condition. The FAA issued AD 2025-06-01 to address partially 
impaired software protection logic for potential large leaks from the 
engine bleed duct inside the engine core compartments, which could 
result in dual engine failure.
    The NPRM was published in the Federal Register on February 23, 2026 
(91 FR 8390). The NPRM was prompted by Transport Canada AD CF-2025-12, 
dated March 4, 2025 (Transport Canada AD CF-2025-12) (also referred to 
as the MCAI), issued by Transport Canada, which is the aviation 
authority for Canada. The MCAI states that Pratt & Whitney developed an 
EEC software update (version 2.12.1, part number 5324158-15) to address 
the detection and protection for potential large leaks. Installation of 
EEC software version 2.12.1 on both engines is a terminating action to 
the AFM revision specified in the MCAI. The MCAI also removes 
production airplanes from the applicability that will have an 
equivalent modification incorporated before delivery.
    In the NPRM, the FAA proposed to continue to require the actions in 
AD 2025-06-01 and require installing a certain EEC software update on 
both engines, as specified in Transport Canada AD CF-2025-12. 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-2026-1336.

Discussion of Final Airworthiness Directive

Comments

    The FAA received a comment from Air Line Pilots Association, 
International (ALPA) who supported the NPRM without change.
    The FAA received additional comments from Delta Air Lines (Delta). 
The following presents the comments received on the NPRM and the FAA's 
response to each comment.

Request To Allow Replacement of the EEC

    Delta requested that the FAA revise paragraph (h)(4) of the 
proposed AD to allow either replacement or modification of the EEC to a 
software version eligible for installation, for added operator 
flexibility. Delta stated that Transport Canada AD CF-2025-12 mandates 
installation of EEC software version V2.12.1 either through replacement 
or modification of the EEC as terminating action of the Transport 
Canada AD. Delta suggested that the ability to either modify or replace 
the EEC would allow operators additional flexibility in AD 
implementation.
    Replacement of an EEC is an optional method of compliance. The FAA 
has revised paragraph (h)(4) of this AD to specify replacement of an 
EEC with an EEC that has EEC software version 2.12.1 or later approved 
version as an optional method of compliance for this AD.

Request To Allow Later Software Versions

    Delta requested that the FAA revise the proposed AD to allow later 
EEC software versions. Delta recommended that the FAA add a new 
paragraph to the proposed AD titled ``Definitions'' and define ``EEC 
Software Version Eligible for Installation'' as ``EEC Software Version 
V2.12.1 or later'' to accommodate future EEC software

[[Page 47952]]

version releases. Delta noted that other FAA ADs for these aircraft 
that have mandated installation of a specific EEC software version have 
allowed for future EEC software versions to be considered as AD-
compliant. Delta suggested that defining an EEC software version 
eligible for installation as V2.12.1 or later would accommodate future 
EEC software versions released by the manufacturer for continued fleet 
reliability improvements and would align with previous ADs with EEC 
software version mandates.
    The FAA agrees to allow later EEC software versions. The FAA 
coordinated with Transport Canada regarding the acceptability of 
specifying later versions of EEC software for this aircraft. While the 
FAA has not revised this AD to add a definitions paragraph, the FAA has 
revised paragraph (h)(4) of this AD to allow later versions of the EEC 
software.

Conclusion

    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 reviewed the relevant 
data, considered any comments received, and determined that air safety 
requires adopting this AD as proposed. Accordingly, the FAA is issuing 
this AD to address the unsafe condition on these products. Except for 
minor editorial changes, and any other changes described previously, 
this AD is adopted as proposed in the NPRM. None of the changes will 
increase the economic burden on any operator.

Material Incorporated by Reference Under 1 CFR Part 51

    Transport Canada AD CF-2025-12 specifies procedures for revising 
the ``Non-Normal Procedure'' of the AFM to incorporate the procedures 
for the flightcrew to manually isolate the opposite functional engine 
in the event of an engine bleed duct large leak condition, and the 
installation of a certain EEC software update on both engines, which 
terminates the AFM revision. The installation consists of updating the 
EEC software to version 2.12.1 by either replacing or modifying the EEC 
to include software version 2.12.1. 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.

Costs of Compliance

    The FAA estimates this AD affects 152 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.
               Action                         Labor cost            Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Retained actions from AD 2025-06-01  1 work-hour x $85 per hour               $0             $85         $12,920
                                      = $85.
New actions (software upgrade).....  10 work-hours x $85 per                   0             850         129,200
                                      hour = $850.
----------------------------------------------------------------------------------------------------------------


                                      Estimated Costs for Optional Actions
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace EEC...................................  9 work-hours x $85 per hour =         $1,291,050      $1,291,815
                                                 $765.
----------------------------------------------------------------------------------------------------------------

    The FAA has determined that it is not likely that operators would 
need to replace the EEC in order to complete the software upgrade; 
therefore, the rule is not significant.
    The FAA has included all known costs in its cost estimate. 
According to the manufacturer, however, some or all of the costs of 
this 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

    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,
    (2) Will not affect intrastate aviation in Alaska, and
    (3) Will 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 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.

[[Page 47953]]

Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by:
0
a. Removing Airworthiness Directive (AD) AD 2025-06-01, Amendment 39-
22989 (90 FR 12457, March 18, 2025); and
0
b. Adding the following new AD:

2026-15-14 Airbus Canada Limited Partnership (Type Certificate 
Previously Held by C Series Aircraft Limited Partnership (CSALP); 
Bombardier, Inc.): Amendment 39-23426; Docket No. FAA-2026-1336; 
Project Identifier MCAI-2025-00254-T.

(a) Effective Date

    This airworthiness directive (AD) is effective September 3, 
2026.

(b) Affected ADs

    This AD replaces AD 2025-06-01, Amendment 39-22989 (90 FR 12457, 
March 18, 2025) (AD 2025-06-01).

(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-2025-12, dated March 4, 2025 (Transport Canada AD CF-
2025-12).

(d) Subject

    Air Transport Association (ATA) of America Code 73, Engine fuel 
and control.

(e) Unsafe Condition

    This AD was prompted by a design review that discovered software 
protection logic for potential large leaks from the engine bleed 
duct inside the engine core compartments was partially impaired. 
Under certain large leak conditions (e.g., a duct burst at a 
specific portion of the engine's bleed ducting), Pratt & Whitney's 
PW1500G engine's electronic engine control (EEC) would not transmit 
the necessary information to the aircraft controller to 
automatically isolate the opposite engine from the leak path in the 
bleed system. In addition, since AD 2025-06-01 was issued, the FAA 
determined the installation of an engine EEC software update must be 
done to address the unsafe condition. The FAA is issuing this AD to 
address the unsafe condition which, if not addressed, could result 
in dual engine failure.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Requirements

    Except as specified in paragraph (h) of this AD: Comply with all 
required actions and compliance times specified in, and in 
accordance with, Transport Canada AD CF-2025-12.

(h) Exceptions to Transport Canada AD CF-2025-12

    (1) Where Transport Canada AD CF-2025-12 refers to September 10, 
2024 (the effective date of Transport Canada AD CF-2024-30, dated 
August 27, 2024), this AD requires using April 22, 2025 (the 
effective date of AD 2025-06-01).
    (2) Where Transport Canada AD CF-2025-12 refers to its effective 
date, this AD requires using the effective date of this AD.
    (3) Where paragraph B. of part I of Transport Canada AD CF-2025-
12 specifies to ``inform all flight crews of these changes in the 
AFM procedures and thereafter operate the aeroplane accordingly,'' 
this AD does not require those actions as those actions are already 
required by existing FAA operating regulations (see 14 CFR 91.9, 14 
CFR 91.505, and 14 CFR 121.137).
    (4) Where the material referenced in Transport Canada AD CF-
2025-12 specifies to replace or modify the EEC to update the EEC 
software to version 2.12.1, this AD requires modifying or replacing 
the EEC to update the EEC software to version 2.12.1 or later 
approved version.

(i) No Reporting Requirement

    Although the material referenced in Transport Canada AD CF-2025-
12 specifies to submit certain information 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: 
[email protected].
    (i) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the responsible Flight Standards Office.
    (ii) AMOCs approved previously for AD 2025-06-01 are approved as 
AMOCs for the corresponding provisions of Transport Canada AD CF-
2025-12 that are required by paragraph (g) of this AD.
    (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.

(k) Additional Information

    For more information about this AD, contact Erica Bayles, 
Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 
98198; phone: 907-271-5844; email: [email protected].

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference of 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-2025-12, dated March 4, 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 [email protected]. 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. 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 www.archives.gov/federal-register/cfr/ibr-locations or email [email protected].

    Issued on July 23, 2026.
Brian Knaup,
Acting Deputy Director, Integrated Certificate Management Division, 
Aircraft Certification Service.
[FR Doc. 2026-15411 Filed 7-29-26; 8:45 am]
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