Rule2025-22630
Airworthiness Directives; Bombardier, Inc., Airplanes
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
December 12, 2025
Effective
January 16, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is adopting a new airworthiness directive (AD) for all Bombardier, Inc., Model CL-600-2A12 (601) and CL-600-2B16 (601-3A, 601- 3R, and 604 Variants) airplanes. This AD was prompted by a determination that new or more restrictive airworthiness limitations are necessary. This AD requires revising the existing maintenance or inspection program, as applicable, to incorporate new or more restrictive airworthiness limitations. The FAA is issuing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 90 Issue 237 (Friday, December 12, 2025)</title>
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[Federal Register Volume 90, Number 237 (Friday, December 12, 2025)]
[Rules and Regulations]
[Pages 57688-57690]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-22630]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-1728; Project Identifier MCAI-2025-00076-T;
Amendment 39-23208; AD 2025-24-11]
RIN 2120-AA64
Airworthiness Directives; Bombardier, Inc., Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
Bombardier, Inc., Model CL-600-2A12 (601) and CL-600-2B16 (601-3A, 601-
3R, and 604 Variants) airplanes. This AD was prompted by a
determination that new or more restrictive airworthiness limitations
are necessary. This AD requires revising the existing maintenance or
inspection program, as applicable, to incorporate new or more
restrictive airworthiness limitations. The FAA is issuing this AD to
address the unsafe condition on these products.
DATES: This AD is effective January 16, 2026.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of January 16,
2026.
ADDRESSES:
AD Docket: You may examine the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2025-1728; 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 <a href="/cdn-cgi/l/email-protection#d9b8baf7a0acb599b8bcabb6f7e5b8f9b1abbcbfe4" http: bombardier.com">bombardier.com</a>">ac.yul@aero.<a href="http://bombardier.com">bombardier.com</a></a>; website <a href="http://bombardier.com">bombardier.com</a>.
<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 <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2025-1728.
FOR FURTHER INFORMATION CONTACT: Joseph Catanzaro, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
phone: 516-228-7300; email: <a href="/cdn-cgi/l/email-protection#e7deca869194ca899e868488ca848894a7818686c9808891"><span class="__cf_email__" data-cfemail="f5ccd8948386d89b8c94969ad8969a86b5939494db929a83">[email protected]</span></a>.
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-600-2A12 (601) and CL-600-2B16 (601-3A, 601-3R, and 604
Variants) airplanes. The NPRM was published in the Federal Register on
August 5, 2025 (90 FR 37434). The NPRM was prompted by AD CF-2025-06,
dated January 20, 2025 (Transport Canada AD CF-2025-06) (also referred
to as the MCAI), issued by Transport Canada, which is the aviation
authority for Canada. The MCAI states that new or more restrictive
airworthiness limitations have been developed. The flightcrew of a
Challenger airplane started the auxiliary power unit (APU) during the
approach and allowed it to run for approximately 10 minutes after
landing. When the flightcrew shut the APU down, an APU FIRE warning
message was posted on the engine indicating and crew alerting system
(EICAS). The APU fire suppression was discharged; however, the fire was
not fully extinguished following the discharge of the fire bottles.
Upon further investigation, it was discovered that a fuel solenoid
valve was leaking, and the APU muffler drainage was blocked leading to
an accumulation of fuel in the muffler. The fuel in the APU muffler was
ignited by the high-temperature exhaust gases in the muffler.
In the NPRM, the FAA proposed to require revising the existing
maintenance or inspection program, as applicable, to incorporate new or
more restrictive airworthiness limitations. The FAA is issuing this AD
to address an accumulation of fuel in the APU muffler caused by a
drainage block in the muffler. This condition, if not corrected, could
lead to an accumulation of fuel in the muffler being ignited by the
high-temperature exhaust gases in the muffler, and could subsequently
lead to an uncontrolled fire in the APU bay.
You may examine the MCAI in the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2025-1728.
Discussion of Final Airworthiness Directive
Comments
The FAA received a comment from Bombardier. The following presents
the comment received on the NPRM and the FAA's response to the comment.
Request To Clarify Source of Fuel Leakage
Bombardier noted the Background section of the proposed AD states
that upon further investigation, it was discovered that a fuel solenoid
valve was leaking. Bombardier stated it was suspected that there was an
internal fuel leakage from the fuel solenoid valve, not that the valve
was found leaking.
The FAA acknowledges Bombardier's request. The FAA notes that the
information in the Background section of the proposed AD restates the
information provided in the MCAI, so 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
[[Page 57689]]
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 the following Bombardier material:
<bullet> Temporary Revision No. 5-2-6, dated June 28, 2024, which
includes new Task 49-15-01-101*, ``Functional Test of the Auxiliary
Power Unit (APU) Muffler Drain.''
<bullet> Temporary Revision No. 5-2-30, dated June 28, 2024, which
includes new Task 49-15-01-101*, ``Functional Test of the Auxiliary
Power Unit (APU) Muffler Drain.''
<bullet> Temporary Revision No. 5-2-74, dated June 28, 2024, which
includes new Task 49-15-01-101*, ``Functional Test of the Auxiliary
Power Unit (APU) Muffler Drain (A/C 5301 to 5630, Post SB 604-49-006,
and A/C 5631 and Subs).''
<bullet> Temporary Revision No. TR 5-271, dated September 30, 2024,
which includes, among other tasks, new Task 49-15-01-101*, ``Functional
Test of the APU Muffler Drain.''
<bullet> Temporary Revision No. TR 5-285, dated September 30, 2024,
which includes, among other tasks, new Task 49-15-01-101*, ``Functional
Test of the APU Muffler Drain.''
(The asterisk (or ``one star'') with the last three digits of the
task numbers listed above indicates that the task is an airworthiness
limitation task.)
Temporary Revision Nos. 5-2-6, 5-2-30, 5-2-74, TR 5-271, and TR 5-
285 introduce, among other tasks, functional tests of the APU muffler
drain. These documents are distinct since they apply to different
airplane configurations.
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 550 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:
The FAA has determined that revising the maintenance or inspection
program takes an average of 90 work-hours per operator, although the
agency recognizes that this number may vary from operator to operator.
Since operators incorporate maintenance or inspection program changes
for their affected fleet(s), the FAA has determined that a per-operator
estimate is more accurate than a per-airplane estimate. Therefore, the
agency estimates the average total cost per operator to be $7,650 (90
work-hours x $85 per work-hour).
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:
2025-24-11 Bombardier, Inc.: Amendment 39-23208; Docket No. FAA-
2025-1728; Project Identifier MCAI-2025-00076-T.
(a) Effective Date
This airworthiness directive (AD) is effective January 16, 2026.
(b) Affected ADs
None.
(c) Applicability
This AD applies to all Bombardier, Inc., Model CL-600-2A12 (601)
and CL-600-2B16 (601-3A, 601-3R, and 604 Variants) airplanes,
certificated in any category.
(d) Subject
Air Transport Association (ATA) of America Code 49, Auxiliary
Power
(e) Unsafe Condition
This AD was prompted by a determination that new or more
restrictive airworthiness limitations are necessary. The FAA is
issuing this AD to address an accumulation of fuel in the auxiliary
power unit (APU) muffler caused by a drainage block in the muffler.
This condition if not corrected, could lead to an accumulation of
fuel in the muffler being ignited by the high-temperature exhaust
gases in the muffler, and could subsequently lead to an uncontrolled
fire in the APU bay.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Maintenance or Inspection Program Revision
Within 90 days after the effective date of this AD, revise the
existing maintenance or inspection program, as applicable, to
incorporate the information specified in the applicable tasks
identified in figure 1 to paragraph (g) of this AD. The initial
compliance time for doing the tasks is at the time specified in the
applicable tasks identified in figure 1 to paragraph (g) of this AD,
or within 90 days after the effective date of this AD, whichever
occurs later.
Figure 1 to Paragraph (g)--Temporary Revisions and Tasks
[[Page 57690]]
[GRAPHIC] [TIFF OMITTED] TR12DE25.000
Note 1 to figure 1 to paragraph (g): The asterisk (or ``one
star'') with the last three digits of the task numbers listed in
table 1 to paragraph (g) of this AD indicates that the task is an
airworthiness limitation task.
(h) No Alternative Actions or Intervals
After the existing maintenance or inspection program has been
revised as required by paragraph (g) of this AD, no alternative
actions (e.g., inspections) or intervals may be used unless the
actions and intervals are approved as an alternative method of
compliance (AMOC) in accordance with the procedures specified in
paragraph (i)(1) of this AD.
(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:
<a href="/cdn-cgi/l/email-protection#c7868a888487a1a6a6e9a0a8b1"><span class="__cf_email__" data-cfemail="edaca0a2aead8b8c8cc38a829b">[email protected]</span></a>. Before using any approved AMOC, notify your
appropriate principal inspector, or lacking a principal inspector,
the manager of the 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'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 Joseph Catanzaro,
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410,
Westbury, NY 11590; phone: 516-228-7300; email: <a href="/cdn-cgi/l/email-protection#fcc5d19d8a8fd192859d9f93d19f938fbc9a9d9dd29b938a"><span class="__cf_email__" data-cfemail="70495d1106035d1e0911131f5d131f03301611115e171f06">[email protected]</span></a>.
(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 Temporary Revision No. 5-2-6, dated June 28,
2024.
(ii) Bombardier Temporary Revision No. 5-2-30, dated June 28,
2024.
(iii) Bombardier Temporary Revision No. 5-2-74, dated June 28,
2024.
(iv) Bombardier Temporary Revision No. TR 5-271, dated September
30, 2024.
(v) Bombardier Temporary Revision No. TR 5-285, dated September
30, 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 <a href="/cdn-cgi/l/email-protection#e9888ac7909c85a9888c9b86c7d588c9819b8c8fd4" http: bombardier.com">bombardier.com</a>">ac.yul@aero.<a href="http://bombardier.com">bombardier.com</a></a>; website
<a href="http://bombardier.com">bombardier.com</a>.
(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 <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#99ffebb7f0f7eae9fcfaedf0f6f7d9f7f8ebf8b7fef6ef"><span class="__cf_email__" data-cfemail="5a3c28743334292a3f392e3335341a343b283b743d352c">[email protected]</span></a>.
Issued on November 24, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2025-22630 Filed 12-11-25; 8:45 am]
BILLING CODE 4910-13-P
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