[Federal Register Volume 90, Number 197 (Wednesday, October 15, 2025)]
[Rules and Regulations]
[Pages 48251-48254]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-19555]
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Rules and Regulations
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains regulatory documents
having general applicability and legal effect, most of which are keyed
to and codified in the Code of Federal Regulations, which is published
under 50 titles pursuant to 44 U.S.C. 1510.
The Code of Federal Regulations is sold by the Superintendent of Documents.
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Federal Register / Vol. 90, No. 197 / Wednesday, October 15, 2025 /
Rules and Regulations
[[Page 48251]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-3432; Project Identifier MCAI-2024-00743-E;
Amendment 39-23171; AD 2025-20-18]
RIN 2120-AA64
Airworthiness Directives; Continental Aerospace Technologies GmbH
Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule; request for comments.
-----------------------------------------------------------------------
SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
Continental Aerospace Technologies GmbH (Continental) Model TAE 125-02-
125 engines. This AD was prompted by multiple reports of cracks in the
cylinder heads, which can cause engine coolant to leak into the
combustion chamber. This AD requires a one-time inspection of the
engine coolant for contamination and, depending on the inspection
results, replacement of the coolant and replacement of the cylinder
heads. This AD also prohibits installing a cylinder head on any engine
unless it is a serviceable part. The FAA is issuing this AD to address
the unsafe condition on these products.
DATES: This AD is effective October 30, 2025.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of October 30,
2025.
The FAA must receive comments on this AD by December 1, 2025.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to regulations.gov. Follow
the instructions for submitting comments.
Fax: (202) 493-2251.
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.
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 regulations.gov under
Docket No. FAA-2025-3432; 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
street address for Docket Operations is listed above.
Material Incorporated by Reference:
For Continental material identified in this AD, contact
Continental, Platanenstrasse 14, 09356 Sankt Egidien, Germany; phone:
+49 37204 696 0; email: continentaldiesel.com">support@continentaldiesel.com; website:
continentaldiesel.com.
You may view this material at the FAA, Operational Safety
Branch, 1200 District Avenue, Burlington, MA 01803. For information on
the availability of this material at the FAA, call (817) 222-5110. It
is also available at regulations.gov under Docket No. FAA-2025-3432.
FOR FURTHER INFORMATION CONTACT: Rawle Thomas, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
phone: (404) 474-5576; email: [email protected].
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written data, views, or arguments
about this final rule. Send your comments using a method listed under
the ADDRESSES section. Include ``Docket No. FAA-2025-3432; Project
Identifier MCAI-2024-00743-E'' at the beginning of your comments. The
most helpful comments reference a specific portion of the final rule,
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 final rule 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
regulations.gov, including any personal information you provide. The
agency will also post a report summarizing each substantive verbal
contact received about this final rule.
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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to Rawle
Thomas, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410,
Westbury, NY 11590. 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 European Union Aviation Safety Agency (EASA), which is the
Technical Agent for the Member States of the European Union, has issued
EASA AD 2024-0236, dated December 10, 2024 (EASA AD 2024-0236) (also
referred to as the MCAI), to correct an unsafe condition on all
Continental Model TAE 125-02-125 engines. The MCAI states that several
cases of cracks in cylinder heads have been reported. The MCAI further
states that these cracks may cause leakage of engine coolant into the
combustion chamber(s), causing loss of coolant, which could lead to
engine overheat and eventual engine failure or seizure. Additionally,
the MCAI states that contamination of the engine coolant, especially
with potassium, triggers certain critical types of chemical corrosion,
depending on the nature of such contamination. The investigation of the
root cause for the cylinder head
[[Page 48252]]
ruptures is still ongoing. Accordingly, the MCAI is considered an
interim action.
This condition, if not addressed, could result in an uncommanded
in-flight shutdown of the engine and a forced landing, which could
result in damage to the airplane and injury to occupants.
You may examine the MCAI in the AD docket at regulations.gov under
Docket No. FAA-2025-3432.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Continental Service Bulletin (SB) CG 125-1030 P1,
Revision 4, dated January 10, 2025. This material specifies procedures
for a one-time inspection of the engine coolant for contamination using
the minimum and maximum acceptable ranges for the two coolant types as
specified in the material. This material also specifies procedures for
labeling the coolant samples.
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 and material referenced above. The FAA is issuing
this AD after determining that the unsafe condition described
previously is likely to exist or develop on other products of the same
type design.
AD Requirements
This AD requires a one-time inspection of the engine coolant for
contamination and, depending on the results, replacing the cylinder
heads with a serviceable part for engines in which the coolant sample
has aluminum or fluoride that exceeds the acceptable range; or draining
and flushing the engine cooling system and refilling it with new
coolant for engines in which the coolant sample exceeds any acceptable
range, except for aluminum and fluoride. This AD also prohibits
installing a cylinder head on any engine unless it is a serviceable
part.
Interim Action
The FAA considers this AD interim action. The unsafe condition is
still under investigation by the manufacturer. If final action is later
identified, the FAA might consider further rulemaking.
Justification for Immediate Adoption and Determination of the Effective
Date
Section 553(b) of the Administrative Procedure Act (APA) (5 U.S.C.
551 et seq.) authorizes agencies to dispense with notice and comment
procedures for rules when the agency, for ``good cause,'' finds that
those procedures are ``impracticable, unnecessary, or contrary to the
public interest.'' Under this section, an agency, upon finding good
cause, may issue a final rule without providing notice and seeking
comment prior to issuance. Further, section 553(d) of the APA
authorizes agencies to make rules effective in less than thirty days,
upon a finding of good cause.
An unsafe condition exists that requires the immediate adoption of
this AD without providing an opportunity for public comments prior to
adoption. The FAA has found that the risk to the flying public
justifies forgoing notice and comment prior to adoption of this rule
because contamination of the engine coolant can cause chemical
corrosion, which could lead to cracks in the cylinder heads and allow
engine coolant to leak into the combustion chamber. Additionally,
cylinder heads are critical components to maintaining controlled
flight. The FAA has no information pertaining to the root cause, the
extent of the root cause that may currently exist in airplanes, or how
quickly the root cause may propagate to failure. Additionally, the
compliance time in this AD for the required actions is within 5 flight
hours (FH) for engines with 50 FH or more since the last engine coolant
replacement or since new, which is shorter than the time necessary for
the public to comment and for publication of the final rule.
Accordingly, notice and opportunity for prior public comment are
impracticable and contrary to the public interest pursuant to 5 U.S.C.
553(b).
In addition, the FAA finds that good cause exists pursuant to 5
U.S.C. 553(d) for making this amendment effective in less than 30 days,
for the same reasons the FAA found good cause to forgo notice and
comment.
Regulatory Flexibility Act
The requirements of the Regulatory Flexibility Act (RFA) do not
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt
a rule without prior notice and comment. Because the FAA has determined
that it has good cause to adopt this rule without prior notice and
comment, RFA analysis is not required.
Costs of Compliance
The FAA estimates that this AD affects 30 engines installed on
airplanes of U.S. registry.
The FAA estimates the following costs to comply with this AD:
Estimated Costs
----------------------------------------------------------------------------------------------------------------
Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Inspect coolant.................... 2 work-hours x $85 per hour $0 $170 $5,100
= $170.
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The FAA estimates the following costs to do any necessary actions
that would be required based on the results of the inspection. The
agency has no way of determining the number of engines that might need
these actions:
On-Condition Costs
----------------------------------------------------------------------------------------------------------------
Cost per
Action Labor cost Parts cost product
----------------------------------------------------------------------------------------------------------------
Drain, flush engine cooling system, and 4 work-hours x $85 per hour = $20 $360
replace coolant. $340.
Replace cylinder head......................... 16 work-hours x $85 per hour = 10,000 11,360
$1,360.
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[[Page 48253]]
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, and
(2) Will not affect intrastate aviation in Alaska.
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:
2025-20-18 Continental Aerospace Technologies GmbH: Amendment 39-
23171; Docket No. FAA-2025-3432; Project Identifier MCAI-2024-00743-
E.
(a) Effective Date
This airworthiness directive (AD) is effective October 30, 2025.
(b) Affected ADs
None.
(c) Applicability
This AD applies to Continental Aerospace Technologies GmbH
(Continental) Model TAE 125-02-125 engines.
(d) Subject
Joint Aircraft System Component (JASC) Code 1240, Coolant
Servicing.
(e) Unsafe Condition
This AD was prompted by multiple reports of cracks in the
cylinder heads, which can cause engine coolant to leak into the
combustion chamber. The root cause of this damage is unknown, and
the investigation is ongoing. The FAA is issuing this AD to detect
and correct contamination of the engine coolant. The unsafe
condition, if not addressed, could result in an uncommanded in-
flight shutdown of the engine and a forced landing, which could
result in damage to the airplane and injury to occupants.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Definition
(1) For the purpose of this AD, a ``serviceable part'' is a
cylinder head which is new (never installed), or a cylinder head
which was not removed in accordance with paragraph (h)(2) of this
AD.
(h) Required Actions
(1) Inspect (sampling and analysis) the engine coolant for
contamination in accordance with Appendix B: Instruction to take
coolant sample, of Continental Service Bulletin CG 125-1030 P1,
Revision 4, dated January 10, 2025 (SB CG 125-1030 P1, Rev 4), at
the applicable time in paragraph (h)(1)(i) or (ii) of this AD:
(i) For engines that have accumulated 50 flight hours (FH) or
more since the last engine coolant replacement or 50 FH or more
since new if the coolant has never been replaced, as of the
effective date of this AD, within 5 FH after the effective date of
this AD.
(ii) For engines that have accumulated less than 50 FH since the
last engine coolant replacement or less than 50 FH since new if the
coolant has never been replaced, as of the effective date of this
AD, within 5 FH after accumulating 50 FH.
(2) If, during any inspection required by paragraph (h)(1) of
this AD, the coolant sample contains aluminum or fluoride that
exceeds the acceptable range as specified in Table 1: Limit values
for G48 coolant type or Table 2: Limit values for G40 coolant type,
as applicable, in Appendix A: Material, Methods and Limits, of SB CG
125-1030 P1, Rev 4, before further flight, remove the cylinder head
and replace it with a serviceable part, flush the engine cooling
system, and refill the cooling system with new coolant.
(3) If, during any inspection required by paragraph (h)(1) of
this AD, the coolant sample exceeds any acceptable range, except for
the aluminum or fluoride ranges, as specified in Table 1: Limit
values for G48 coolant type or Table 2: Limit values for G40 coolant
type, as applicable, in Appendix A: Material, Methods and Limits, of
SB CG 125-1030 P1, Rev 4, before further flight, drain and flush the
engine cooling system and refill the cooling system with new
coolant.
(i) Installation Prohibition
After the effective date of this AD, do not install on any
engine a cylinder head that is not a ``serviceable part,'' as
defined in paragraph (g)(1) of this AD.
(j) Credit for Previous Actions
This paragraph provides credit for the inspections and part
replacements required by paragraph (h) of this AD, if those actions
were performed before the effective date of this AD using
Continental Service Bulletin CG 125-1030 P1, Revision 3, dated
September 16, 2024.
(k) Alternative Methods of Compliance (AMOCs)
(1) 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 local Flight
Standards District 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 (l) of
this AD and email to [email protected].
(2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the local flight standards district office/certificate holding
district office.
(l) Additional Information
(1) For more information about this AD, contact Rawle Thomas,
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410,
Westbury, NY 11590; phone: (404) 474-5576; email:
[email protected].
(2) For Continental material, which is not incorporated by
reference in this AD, contact Continental, Platanenstrasse 14, 09356
Sankt Egidien, Germany; phone: +49 37204 696 0; email:
continentaldiesel.com">support@continentaldiesel.com; website: continentaldiesel.com.
(m) 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 the AD specifies otherwise.
(i) Continental Aerospace Technologies GmbH (Continental)
Service Bulletin CG 125-1030 P1, Revision 4, dated January 10, 2025.
(ii) [Reserved]
(3) For Continental material identified in this AD, contact
Continental, Platanenstrasse 14, 09356 Sankt Egidien, Germany;
phone:
[[Page 48254]]
+49 37204 696 0; email: continentaldiesel.com">support@continentaldiesel.com; website:
continentaldiesel.com.
(4) You may view this material at the FAA, Operational Safety
Branch, 1200 District Avenue, Burlington, MA 01803. For information
on the availability of this material at the FAA, call (817) 222-
5110.
(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 October 3, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2025-19555 Filed 10-14-25; 8:45 am]
BILLING CODE 4910-13-P