Airworthiness Directives; Bombardier, Inc., Airplanes

[Federal Register Volume 90, Number 220 (Tuesday, November 18, 2025)]
[Rules and Regulations]
[Pages 51501-51504]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-20064]



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Federal Register / Vol. 90, No. 220 / Tuesday, November 18, 2025 / 
Rules and Regulations

[[Page 51501]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-0483; Project Identifier MCAI-2024-00523-T; 
Amendment 39-23182; AD 2025-22-04]
RIN 2120-AA64


Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
Bombardier, Inc., Model CL-600-2B16 (604 Variant) airplanes. This AD 
was prompted by reports that the flap system on-board recorder (FSOBR) 
interfaces with the flap control unit signals and may result in the 
flap control unit monitors tripping, causing Flap Fail messages and 
possibly an uncommanded flap movement. This AD requires the 
disconnection of the FSOBR and prohibits future installation of this 
system. The FAA is issuing this AD to address the unsafe condition on 
these products.

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

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2025-0483; 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 Bombardier material identified in this AD, contact 
Bombardier Business Aircraft Customer Response Center, 400 C[ocirc]te-
Vertu Road West, Dorval, Qu[eacute]bec H4S 1Y9, Canada; telephone 514-
855-2999; email bombardier.com">ac.yul@aero.bombardier.com; website bombardier.com.
    <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-2025-0483.

FOR FURTHER INFORMATION CONTACT: Steven Dzierzynski, Aviation Safety 
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; 
phone: 516-228-7300; email: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to all Bombardier, Inc., 
Model CL-600-2B16 (604 Variant) airplanes. The NPRM was published in 
the Federal Register on April 7, 2025 (90 FR 14929). The NPRM was 
prompted by AD CF-2024-31R1, dated December 17, 2024 (Transport Canada 
AD CF-2024-31R1) (also referred to as the MCAI), issued by Transport 
Canada, which is the aviation authority for Canada. The MCAI states 
that the FSOBR interfaces with the flap control unit Input/Output (I/O) 
signals and may result in the flap control unit monitors tripping, 
causing Flap Fail messages and possibly an uncommanded flap movement. 
This event combined with other flap system failures can lead to an 
uncommanded flap runaway. This condition, if not addressed, could lead 
to loss of control of the airplane.
    In the NPRM, the FAA proposed to require the disconnection of the 
FSOBR and prohibit future installation of this system. 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-2025-0483.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from The Boeing Company (Boeing) and an 
anonymous commenter. The following presents the comments received on 
the NPRM and the FAA's response to each comment.

Request for Clarification on FSOBR Unit

    Boeing requested clarification on the state of the FSOBR unit. 
Boeing stated that paragraph (h) of the proposed AD conflicts with 
Bombardier Service Bulletin 650-27-005, dated May 20, 2024, because the 
service bulletin does not require the removal of FSOBR unit, part 
number (P/N) 604-70201-1.
    The FAA notes that this AD does not require removal of an affected 
FSOBR from the airplane. Instead, paragraph (g) of this AD requires 
disconnection of the FSOBR, which is consistent with the service 
bulletin instructions and other service bulletins referenced in table 1 
to paragraph (g) of this AD. In addition, paragraph (h) of this AD 
prohibits installation of an affected FSOBR or FSOBR harness on or 
after the effective date of this AD, and reconnection of an FSOBR if 
one was installed on the airplane before the effective date of this AD. 
No change to the AD is necessary in this regard.

Request for Oversight of AD Compliance

    The anonymous commenter requested that the FAA require all affected 
aircraft operators to submit documentation of completed FSOBR 
disconnect, and mandate an independent verification process to ensure 
compliance, with public reporting of results for transparency.
    The FAA does not agree with the request. In certain cases, the FAA 
might determine that additional information (i.e., data collection) is 
needed to understand the problem and develop appropriate mitigation for 
an unsafe condition. In this case, the unsafe condition was identified, 
and a corrective action was developed, without the need to require 
operator reports. However, an operator may still choose to send 
relevant information to the FAA. The FAA has not changed this AD in 
this regard.

[[Page 51502]]

Request To Track and Report Flap Control Incidents

    The anonymous commenter requested that the FAA collect and publicly 
release data on any post-AD incidents involving flap control systems on 
Bombardier, Inc., Model CL-600-2B16 (604 Variant) airplanes for at 
least five years, to track effectiveness and spot emerging risks.
    Under the bilateral agreement between Canada and the U.S., 
Transport Canada and the FAA have established implementation procedures 
specifying that the certificating authority is required to collect and 
analyze any data, and notify the other foreign authority of all known 
unsafe conditions and any necessary corrective actions. In this case, 
Transport Canada is the certificating authority for Bombardier 
aircraft. The FAA notes that U.S. operators may also submit any 
incidents to the service difficulty reporting (SDR) system at 
sdrs.faa.gov, which is accessible to the public. No change to the AD is 
necessary in this regard.

Request To Require Root Cause Analysis and Collaboration

    The anonymous commenter requested that the FAA require 
manufacturers to conduct and publish root-cause analysis of FSOBR 
failures and collaborate with labor and consumer safety groups in 
designing future onboard systems to avoid similar risks.
    The FAA does not agree. As discussed in the previous comment, 
Transport Canada will continue to collect and analyze reports regarding 
the FSOBR system. The FAA has not revised the AD in this regard.

Request To Offset Economic Burden on Small Operators

    The anonymous commenter requested the FAA ensure that warranty 
coverage, reimbursement, or federal funding is accessible to offset 
compliance costs and prevent a disproportionate economic burden on 
smaller businesses or regional carriers.
    The FAA recognizes that this AD imposes certain operational costs 
on operators, and that operators have an obligation to maintain their 
airplanes in airworthy condition. However, the FAA does not mandate 
warranty coverage, reimbursement, or federal funding, and has not 
changed this AD in this regard.

Request To Provide Compliance Time Flexibility for Small Operators

    The anonymous commenter requested that the FAA provide targeted 
support or flexibility for compliance timelines to operators serving 
rural, low-income, or remote communities, ensuring continued access to 
Essential Air Services.
    The FAA does not agree. The compliance time for this AD was 
developed based on the recommendations of Transport Canada and the 
manufacturer, the urgency associated with the subject unsafe condition, 
and the practical aspect of accomplishing the required actions. The FAA 
has determined that the compliance time required by this AD will ensure 
an appropriate level of safety. The FAA has not changed this AD in this 
regard.

Request for Certified Personnel To Perform Work, With Whistleblower 
Protection

    The anonymous commenter requested that the FAA require only FAA-
certified technicians to perform the FSOBR maintenance and disconnect 
procedures, with explicit whistleblower protections for reporting 
safety lapses or procedural shortcuts.
    The FAA notes that FAA regulations require maintenance, 
preventative maintenance, and alterations be performed by certified 
personnel (14 CFR 43.3 and 43.17). Further, the Wendell H. Ford 
Aviation Investment and Reform Act for the 21st Century (49 U.S.C. 
42121) prohibits discrimination against employees of the U.S. air 
carrier industry and U.S. manufacturers who report information related 
to air carrier safety. More information about the FAA AIR-21 
Whistleblower Protection Program is available at https://www.faa.gov/about/initiatives/whistleblower. No change to the AD is necessary in 
this regard.

Request To Include Stakeholder Input

    The anonymous commenter requested that the FAA solicit feedback 
from frontline aviation workers and labor unions on the effectiveness 
and challenges of the FSOBR removal process, especially regarding time 
and resource requirements.
    The FAA notes that this AD requires a disconnect of the FSOBR 
harness, not removal of the FSOBR. The FAA also notes that it invites 
industry stakeholders to participate in the rulemaking process by 
providing notice of the proposed rule in the Federal Register. Before 
issuing the final rule, the FAA considers all comments received and 
determines whether air safety requires incorporating any requested 
changes or adopting the AD as proposed. No change to the AD is 
necessary in this regard.

Request To Coordinate With International Regulators

    The anonymous commenter requested that the FAA ensure continued 
close coordination with Transport Canada and other international 
regulators to harmonize safety standards and avoid creating regulatory 
loopholes that could undermine safety or equity.
    The FAA notes that the FAA has bilateral agreements with 
international civil aviation authorities, including Transport Canada, 
to ensure aviation regulations are harmonized as much as practicable. 
No change to the AD is necessary in this regard.

Request To Address Safe Handling and Disposal of Hazardous Materials

    The anonymous commenter requested that the FAA ensure that all 
FSOBR removal and disposal processes comply with Occupational Safety 
and Health Administration (OSHA) guidelines for hazardous material 
handling and require environmentally safe disposal of all electronic 
components.
    The FAA acknowledges the commenter's concern. However, the FAA 
notes that this AD requires disconnecting the FSOBR harness, not 
removal and disposal of the FSOBR or other electrical components. No 
change to the AD is necessary in this regard.

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

    The FAA reviewed Bombardier Service Bulletins 650-27-005, 605-27-
012, and 604-27-041, all dated May 20, 2024. This material specifies 
procedures to disconnect the FSOBR. These documents are distinct since 
they apply to different airplane serial numbers. This material is 
reasonably available because the interested parties have access to it 
through their normal course

[[Page 51503]]

of business or by the means identified in the ADDRESSES section.

Costs of Compliance

    The FAA estimates that this AD affects 442 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                      Estimated Costs for Required Actions
----------------------------------------------------------------------------------------------------------------
              Labor cost                      Parts cost            Cost per product     Cost on U.S.  operators
----------------------------------------------------------------------------------------------------------------
Up to 3 work-hours x $85 per hour =    Minimal................  Up to $255.............  Up to $112,710.
 $255.
----------------------------------------------------------------------------------------------------------------

    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.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2025-22-04 Bombardier, Inc.: Amendment 39-23182; Docket No. FAA-
2025-0483; Project Identifier MCAI-2024-00523-T.

(a) Effective Date

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

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all Bombardier, Inc., Model CL-600-2B16 (604 
Variant) airplanes, certificated in any category.

(d) Subject

    Air Transport Association (ATA) of America Code 27, Flight 
Controls.

(e) Unsafe Condition

    This AD was prompted by reports that the flap system on-board 
recorder (FSOBR) interfaces with the flap control unit signals and 
may result in the flap control unit monitors tripping, causing Flap 
Fail messages and possibly an uncommanded flap movement. The FAA is 
issuing this AD to address uncommanded flap runaway. The unsafe 
condition, if not addressed, could lead to loss of control of the 
airplane.

(f) Compliance

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

(g) FSOBR Disconnection

    For airplanes that have incorporated Bombardier Service Bulletin 
604-27-035, Bombardier Service Bulletin 605-27-006, or Bombardier 
Service Bulletin 650-27-001 as of the effective date of this AD: 
Within 1,000 flight hours or 14 months, whichever occurs first, 
after the effective date of this AD, disconnect the FSOBR in 
accordance with Section 2.B of the Accomplishment Instructions of 
the applicable service bulletin listed in table 1 to paragraph (g) 
of this AD.

[[Page 51504]]

[GRAPHIC] [TIFF OMITTED] TR18NO25.033

(h) Parts Installation Prohibition

    As of the effective date of this AD, no person may reconnect or 
install any FSOBR unit part number (P/N) (604-70201-1) or FSOBR 
harness P/N (604-57140-3) on any airplane.

(i) Additional AD Provisions

    The following provisions also apply to this AD:
    (1) Alternative Methods of Compliance (AMOCs): The Manager, 
International Validation 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 
International Validation Branch, send it to the attention of the 
person identified in paragraph (j) 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, International 
Validation Branch, FAA; or Transport Canada; or Bombardier, Inc.'s 
Transport Canada Design Approval Organization (DAO). If approved by 
the DAO, the approval must include the DAO-authorized signature.

(j) Additional Information

    For more information about this AD, contact Steven Dzierzynski, 
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; phone: 516-228-7300; email: [email protected].

(k) 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) Bombardier Service Bulletin 604-27-041, dated May 20, 2024.
    (ii) Bombardier Service Bulletin 605-27-012, dated May 20, 2024.
    (iii) Bombardier Service Bulletin 650-27-005, dated May 20, 
2024.
    (3) For Bombardier material identified in this AD, contact 
Bombardier Business Aircraft Customer Response Center, 400 
C[ocirc]te-Vertu Road West, Dorval, Qu[eacute]bec H4S 1Y9, Canada; 
telephone 514-855-2999; email bombardier.com">ac.yul@aero.bombardier.com; website 
bombardier.com.
    (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 November 10, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2025-20064 Filed 11-17-25; 8:45 am]
BILLING CODE 4910-13-P

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