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

[Federal Register Volume 90, Number 179 (Thursday, September 18, 2025)]
[Rules and Regulations]
[Pages 44959-44961]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-18088]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-0344; Project Identifier MCAI-2024-00638-T; 
Amendment 39-23141; AD 2025-19-01]
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) 2022-25-
51, which applied to all Airbus Canada Limited Partnership Model BD-
500-1A10 and Model BD-500-1A11 airplanes. AD 2022-25-51 required 
revising the Limitations section of the existing airplane flight manual 
(AFM) to include a new warning and a new limitation. Since the FAA 
issued AD 2022-25-51, updated primary flight control computer (PFCC) 
software has been developed to address the unsafe condition. This AD 
continues to require the actions in AD 2022-25-51, requires installing 
the updated PFCC software, which terminates the AFM revision, and 
removes airplanes from the applicability. The FAA is issuing this AD to 
address the unsafe condition on these products.

DATES: This AD is effective October 23, 2025.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of October 23, 
2025.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2025-0344; 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-2025-0344.

FOR FURTHER INFORMATION CONTACT: Rochelle Montgomery, Aviation Safety 
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; 
telephone 405-798-2043; email [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to supersede AD 2022-25-51, Amendment 39-22282 (87 FR 
75911, December 12, 2022) (AD 2022-25-51). AD 2022-25-51 applied to all 
Airbus Canada Limited Partnership Model BD-500-1A10 and Model BD-500-
1A11 airplanes. AD 2022-25-51 required revising the Limitations section 
of the existing AFM by revising the title of the existing autopilot AFM 
limitation, including a new warning prior to the existing autopilot 
engagement limitations, and a new limitation prohibiting selecting or 
reselecting autothrottle during takeoff after thrust levers are 
advanced to the takeoff setting after the existing autopilot engagement 
limitations. The FAA issued AD 2022-25-51 to address inadvertent 
engagement of the autopilot below 400 feet above ground level (AGL) 
when the flightcrew attempts to engage autothrottle. The unsafe 
condition, if not addressed, could result in premature rotation due to 
inadvertent autopilot engagement, possibly leading to tail-strike, 
inability to climb, and loss of control of the airplane.
    The NPRM was published in the Federal Register on March 18, 2025 
(90 FR 12498). The NPRM was prompted by AD CF-2024-36, dated October 
22, 2024, issued by Transport Canada, which is the aviation authority 
for Canada (Transport Canada AD CF-2024-36) (also referred to as the 
MCAI). The MCAI states that there have been multiple in-service reports 
associated with PFCC software deficiencies leading to nuisance messages 
on the engine-indicating and crew-alerting system (EICAS) such as 
rudder fail, aileron fail, and spoiler fail, and flight control fault 
due to erroneous transmissions from the remote electronic unit (REU). 
Investigations also indicated design deficiencies in the PFCC software 
such as an incorrectly implemented built-in test, which is unable to 
detect a failed REU internal hold-up capacitor, or non-implemented 
self-tests and monitoring mechanisms to prevent erroneous computations 
to be transmitted to consumers. Other in-service events indicated a 
lack of software robustness, which may not prevent an un-annunciated 
deployment of ground spoilers or an inadvertent autopilot engagement 
during the take-off roll. These deficiencies and lack of PFCC software 
robustness, if not corrected, could lead to increased flightcrew 
workload as well as a large reduction of safety margins. Additionally, 
during specific flight phases or in combination with other failures, 
these conditions could lead to loss of control of the airplane. The 
updated software installation required by this AD addresses the unsafe 
condition identified in AD 2022-25-51 and terminates the AFM revision 
required by AD 2022-25-51.
    In the NPRM, the FAA proposed to continue to require the actions in 
AD 2022-25-51, require installing the updated PFCC software, which 
terminates the AFM revision, and remove airplanes from the 
applicability, as specified in Transport Canada AD CF-2024-36. 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-2025-0344.

[[Page 44960]]

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from Air Line Pilots Association, 
International (ALPA) who supported the NPRM without change.
    The FAA received an additional comment from an individual commenter 
that did not make a request related to the NPRM.

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, 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-2024-36 specifies procedures for revising 
the Limitations section of the existing AFM to include a new warning, 
installation of updated PFCC software part number 810-0337-009 on the 
three PFCCs, which terminates the AFM revision, and applicable 
concurrent software updates. 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 that this AD affects 133 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                                          Estimated Costs for Required Actions
--------------------------------------------------------------------------------------------------------------------------------------------------------
               Action                        Labor cost                 Parts cost                 Cost per product            Cost on U.S. operators
--------------------------------------------------------------------------------------------------------------------------------------------------------
Retained actions from AD 2022-25-51.  1 work-hour x $85 per    $0..........................  $85.........................  $11,305.
                                       hour = $85.
New actions.........................  Up to 5 work-hours x     Up to $10,000...............  Up to $10,425...............  Up to $1,386,525.
                                       $85 per hour = $425.
--------------------------------------------------------------------------------------------------------------------------------------------------------

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.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by:
0
a. Removing Airworthiness Directive (AD) 2022-25-51, Amendment 39-22282 
(87 FR 75911, December 12, 2022); and
0
b. Adding the following new AD:

2025-19-01 Canada Limited Partnership (Type Certificate Previously 
Held by C Series Aircraft Limited Partnership (CSALP); Bombardier, 
Inc.): Amendment 39-23141; Docket No. FAA-2025-0344; Project 
Identifier MCAI-2024-00638-T.

(a) Effective Date

    This airworthiness directive (AD) is effective October 23, 2025.

(b) Affected ADs

    This AD replaces AD 2022-25-51, Amendment 39-22282 (87 FR 75911, 
December 12, 2022) (AD 2022-25-51).

(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 Model BD-500-1A11 
airplanes, certificated in any category, as identified in Transport 
Canada AD CF-2024-36, dated October 22, 2024 (Transport Canada AD 
CF-2024-36).

(d) Subject

    Air Transport Association (ATA) of America Code 22, Autoflight.

(e) Unsafe Condition

    This AD was prompted by multiple in-service reports associated 
with primary flight control computer (PFCC) software deficiencies 
leading to nuisance messages on the engine-indicating and crew-
alerting system (EICAS) due to erroneous transmissions from the 
remote electronic unit (REU). Investigations also indicated design 
deficiencies in the PFCC software and a lack of software robustness, 
which may not prevent an un-annunciated deployment of ground 
spoilers or an inadvertent autopilot engagement during the take-off 
roll. The FAA is issuing this AD to address the PFCC software 
deficiencies leading to nuisance messages and the lack of PFCC 
software robustness. The unsafe condition, if not addressed, could 
lead to increased flightcrew workload as well as a large reduction 
of

[[Page 44961]]

safety margins. Additionally, during specific flight phases or in 
combination with other failures, these conditions could lead to loss 
of control of the airplane.

(f) Compliance

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

(g) Retained Revision of Existing AFM, With No Changes

    This paragraph restates the requirements of paragraph (g) of AD 
2022-25-51, with no changes. Within 7 days after December 27, 2022 
(the effective date of AD 2022-25-51), revise the Limitations 
section of the existing airplane flight manual (AFM) to include the 
information specified in figure 1 to paragraph (g) of this AD. This 
may be accomplished by inserting a copy of figure 1 to paragraph (g) 
of this AD into the existing AFM. Using an AFM revision that 
includes information identical to that in figure 1 to paragraph (g) 
of this AD is acceptable for compliance with the requirement of this 
paragraph.

Figure 1 to Paragraph (g)--Autopilot and Autothrottle Engagement 
Limitation
[GRAPHIC] [TIFF OMITTED] TR18SE25.010

(h) New Requirements of This AD

    Except as specified in paragraph (i) of this AD: Comply with all 
required actions and compliance times specified in, and in 
accordance with, Transport Canada AD CF-2024-36. Accomplishing the 
software installation required by paragraph A. of Part II of 
Transport Canada AD CF-2024-36 terminates the AFM revision required 
by paragraph (g) of this AD.

(i) Exceptions to Transport Canada AD CF-2024-36

    (1) This AD does not adopt the requirements of Part I of 
Transport Canada AD CF-2024-36.
    (2) Where Transport Canada AD CF-2024-36 refers to its effective 
date, this AD requires using the effective date of this AD.
    (3) For the airplanes identified in the ``Concurrent 
requirements'' paragraph of the material referenced in Transport 
Canada AD CF-2024-36: At the applicable time specified in paragraph 
(i)(3)(i) or (ii) of this AD, accomplish the concurrent PFCC 
software update specified in the material referenced in Transport 
Canada AD CF-2024-36.
    (i) For airplanes identified in AD 2023-12-09, Amendment 39-
22467 (88 FR 42606, July 3, 2023) (AD 2023-12-09): Prior to or 
concurrently with the installation specified in paragraph A. of Part 
II of Transport Canada AD CF-2024-36 but no later than the 
compliance time specified in AD 2023-12-09.
    (ii) For airplanes not identified in AD 2023-12-09: Prior to or 
concurrently with the installation specified in paragraph A. of Part 
II of Transport Canada AD CF-2024-36.

(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].
    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.

(k) Additional Information

    For more information about this AD, contact Rochelle Montgomery, 
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; telephone 405-798-2043; email 
[email protected].

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) 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-2024-36, dated October 22, 2024.
    (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 September 15, 2025.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2025-18088 Filed 9-17-25; 8:45 am]
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