Proposed Rule2025-20088
Airworthiness Directives; International Aero Engines AG Engines
Primary source
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Published
November 18, 2025
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to adopt a new airworthiness directive (AD) for certain International Aero Engines AG (IAE AG) Model V2522-A5, V2524-A5, V2525-D5, V2527-A5, V2527E-A5, V2527M-A5, V2528-D5, V2530-A5, V2531-E5, and V2533-A5 engines. This proposed AD was prompted by a manufacturer investigation that revealed that certain 3rd stage HPC rotor blades were susceptible to shroud wear and blade failure. This proposed AD would require replacement of affected 3rd stage HPC rotor blades with parts eligible for installation. The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 90 Issue 220 (Tuesday, November 18, 2025)</title>
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[Federal Register Volume 90, Number 220 (Tuesday, November 18, 2025)]
[Proposed Rules]
[Pages 51600-51602]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-20088]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-2555; Project Identifier AD-2025-00433-E]
RIN 2120-AA64
Airworthiness Directives; International Aero Engines AG Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain International Aero Engines AG (IAE AG) Model V2522-A5,
V2524-A5, V2525-D5, V2527-A5, V2527E-A5, V2527M-A5, V2528-D5, V2530-A5,
V2531-E5, and V2533-A5 engines. This proposed AD was prompted by a
manufacturer investigation that revealed that certain 3rd stage HPC
rotor blades were susceptible to shroud wear and blade failure. This
proposed AD would require replacement of affected 3rd stage HPC rotor
blades with parts eligible for installation. The FAA is proposing this
AD to address the unsafe condition on these products.
DATES: The FAA must receive comments on this proposed AD by January 2,
2026.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="http://regulations.gov">regulations.gov</a>. Follow
the instructions for submitting comments.
<bullet> Fax: (202) 493-2251.
<bullet> 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.
<bullet> 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 <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2025-2555; 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 NPRM, any comments received, and other
information. The street address for Docket Operations is listed above.
FOR FURTHER INFORMATION CONTACT: Carol Nguyen, Aviation Safety
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone:
(781) 238-7655; email: <a href="/cdn-cgi/l/email-protection#610200130e0d4f0f061418040f210700004f060e17"><span class="__cf_email__" data-cfemail="c5a6a4b7aaa9ebaba2b0bca0ab85a3a4a4eba2aab3">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments using a method listed
under the ADDRESSES section. Include ``Docket No. FAA-2025-2555;
Project Identifier AD-2025-00433-E'' at the beginning of your comments.
The most helpful comments reference a specific portion of the proposal,
explain the reason for any recommended change, and include supporting
data. The FAA will consider all comments received by the closing date
and may revise this proposal 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
<a href="http://regulations.gov">regulations.gov</a>, including any personal information you provide. The
agency will also post a report summarizing each substantive verbal
contact received about this NPRM.
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 NPRM 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 NPRM, 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 NPRM. Submissions containing CBI should be sent to Carol
Nguyen, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des
Moines, WA 98198. 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 FAA received multiple reports of failed 3rd stage HPC rotor
blades that resulted in engine fires, unplanned engine removals,
aborted takeoffs, and in-flight shutdowns (IFSD). A manufacturer
investigation revealed that 3rd stage HPC rotor blade part numbers (P/
Ns) 6A8353 or 6A8688, installed on IAE AG Model V2522-A5, V2524-A5,
[[Page 51601]]
V2525-D5, V2527-A5, V2527E-A5, V2527M-A5, V2528-D5, V2530-A5, V2531-E5,
and V2533-A5 engines were susceptible to shroud wear and blade
fractures. As a result, the manufacturer has developed an improved
coating process that increases the durability of the shroud coating,
mitigating wear and reducing the risk of blade fractures. This
condition, if not addressed, could result in engine fire, reduced
control of the airplane, and engine IFSD.
FAA's Determination
The FAA is issuing this NPRM after determining that the unsafe
condition described previously is likely to exist or develop on other
products of the same type design.
Proposed AD Requirements in This NPRM
This proposed AD would require a full set replacement of affected
3rd stage HPC rotor blades with parts eligible for installation.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 1,496 engines installed on aircraft of U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD:
Estimated Costs
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Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Replace full set of 3rd stage HPC rotor 1 work-hours x $85 per hour $30,000 $30,085 $45,007,160
blades with reworked blades. = $85.
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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
The FAA determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 this proposed
regulation:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866,
(2) Would not affect intrastate aviation in Alaska, and
(3) Would 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 Proposed Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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:
International Aero Engines AG: Docket No. FAA-2025-2555; Project
Identifier AD-2025-00433-E.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by January 2, 2026.
(b) Affected ADs
None.
(c) Applicability
This AD applies to International Aero Engines AG (IAE AG) Model
V2522-A5, V2524-A5, V2525-D5, V2527-A5, V2527E-A5, V2527M-A5, V2528-
D5, V2530-A5, V2531-E5, and V2533-A5 engines with a 3rd stage high-
pressure compressor (HPC) rotor blade having part numbers (P/N)
6A8353 or P/N 6A8688 installed.
(d) Subject
Joint Aircraft System Component (JASC) Code 7230, Turbine Engine
Compressor Section.
(e) Unsafe Condition
This AD was prompted by multiple reports of failed 3rd stage HPC
rotor blades that resulted in engine fires, unplanned engine
removals, aborted takeoffs, and in-flight shutdowns (IFSD). The FAA
is issuing this AD to prevent failure of the 3rd stage HPC rotor
blades. The unsafe condition, if not addressed, could result in
engine fire, reduced control of the airplane, and engine IFSD.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
At the next 3rd stage HPC rotor blade exposure after the
effective date of this AD, replace the full set of 3rd stage HPC
rotor blades with parts eligible for installation.
(h) Definitions
(1) For the purpose of this AD, a ``part eligible for
installation'' is:
(i) A 3rd stage HPC rotor blade having P/N 6C8368, 6C8403, or
later approved P/N; or
(ii) A 3rd stage HPC rotor blade modified to P/N 6A8353-001 or
P/N 6A8688-001.
(2) For the purpose of this AD, a ``3rd stage HPC rotor blade
exposure'' is when any 3rd stage HPC rotor blade is removed from the
HPC stage 3 to 8 drum.
(i) Alternative Methods of Compliance (AMOCs)
(1) 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 local
Flight Standards District Office, as appropriate. If sending
information directly to the manager of the AIR-520 Continued
Operational Safety 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#c2838f8d8182a4a3a3eca5adb4"><span class="__cf_email__" data-cfemail="7435393b37341215155a131b02">[email protected]</span></a>.
(2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
[[Page 51602]]
of the local flight standards district office/certificate holding
district office.
(j) Additional Information
For more information about this AD, contact Carol Nguyen,
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines,
WA 98198; phone: (781) 238-7655; email: <a href="/cdn-cgi/l/email-protection#117270637e7d3f7f766468747f517770703f767e67"><span class="__cf_email__" data-cfemail="5b383a29343775353c2e223e351b3d3a3a753c342d">[email protected]</span></a>.
(k) Material Incorporated by Reference
None.
Issued on September 19, 2025.
Lona C. Saccomando,
Acting Deputy Director, Integrated Certificate Management Division,
Aircraft Certification Service.
[FR Doc. 2025-20088 Filed 11-17-25; 8:45 am]
BILLING CODE 4910-13-P
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