[Federal Register Volume 91, Number 160 (Thursday, August 20, 2026)]
[Rules and Regulations]
[Pages 53713-53717]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-16954]



========================================================================
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. 

========================================================================


Federal Register / Vol. 91, No. 160 / Thursday, August 20, 2026 / 
Rules and Regulations

[[Page 53713]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-2555; Project Identifier AD-2025-00433-E; 
Amendment 39-23446; AD 2026-17-03]
RIN 2120-AA64


Airworthiness Directives; International Aero Engines AG Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: The FAA is adopting 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 AD was prompted by a manufacturer 
investigation that revealed that certain 3rd stage high pressure 
compressor (HPC) rotor blades were susceptible to shroud wear and blade 
failure. This AD requires replacement of affected 3rd stage HPC rotor 
blades with parts eligible for installation. The FAA is issuing this AD 
to address the unsafe condition on these products.

DATES: This AD is effective September 24, 2026.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov 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 final rule, 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.

FOR FURTHER INFORMATION CONTACT: Carol Nguyen, Aviation Safety 
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: 
(781) 238-7655; 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 certain 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. The NPRM was published in the 
Federal Register on November 18, 2025 (90 FR 51600). The NPRM 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). A manufacturer investigation revealed 
that 3rd stage HPC rotor blade part numbers (P/Ns) 6A8353 and 6A8688, 
installed on 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 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. In the NPRM, the FAA proposed to 
require a full set replacement of affected 3rd stage HPC rotor blades 
with parts eligible for installation. The FAA is issuing this AD to 
address the unsafe condition on these products.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from seven commenters. Commenters 
included the Air Line Pilots Association, International (ALPA), 
American Airlines, Citizens Rulemaking Alliance, InterGlobe Aviation 
Limited (IndiGo), Lufthansa Technik, SIA Engineering Company (SIAEC), 
and United Airlines. ALPA supported the NPRM without change. The 
following presents the comments received on the NPRM and the FAA's 
response to each comment.

Request Regarding Withdrawing the NPRM

    Lufthansa Technik commented that a change of category code may be 
sufficient to address the unsafe condition rather than an NPRM because 
the current failure mode for 3rd stage HPC rotor blades having P/N 
6A8353 is not as serious as it was with older blades. Lufthansa Technik 
stated that IAE AG issued Service Bulletin (SB) V2500-ENG-72-0487, 
which introduced the current blade standard, and no corresponding AD 
was published at that time. Lufthansa Technik also stated that prior to 
the issuance of SB V2500-ENG-72-0487, 3rd stage HPC rotor blades 
fractured below platform but currently, either the clapper breaks off 
or the blade fracture occurs above platform, making the unsafe 
condition less severe and the necessity of an NPRM doubtful.
    The FAA infers that the commenter is requesting that the NPRM be 
withdrawn. The FAA disagrees with the request. The FAA has identified 
airworthiness limitations and maintenance requirements as mandatory for 
an airplane's continued airworthiness. An operator's failure to 
accomplish these instructions could result in a variety of unsafe 
conditions, including rotor blade failure, which could result in engine 
fire, reduced control of the airplane, and engine IFSD.
    In addition, the FAA may issue ADs to require actions to address 
unsafe conditions that are not otherwise being addressed (or are not 
addressed adequately) by normal maintenance procedures. The FAA may 
address such unsafe conditions by requiring revisions to maintenance or 
inspection programs, as applicable, as a condition under which 
airplanes may continue to be operated. The FAA has therefore determined 
that it is necessary to issue this final rule. The FAA did not change 
this AD as a result of this comment.

Request To Issue an NPRM or Justify Forgoing Notice and Comment

    The Citizens Rulemaking Alliance requested that the FAA either 
convert this action to an NPRM with an expedited comment period and 
adopt an immediately effective interim AD only for tasks with 
compliance times that would lapse before the NPRM could be finalized or 
provide its justification for finding good cause to bypass notice and

[[Page 53714]]

comment procedures. Additionally, the commenter requested that the FAA 
provide the standard 30-day delayed effective date for non-urgent 
provisions. The commenter asserted the FAA has not adequately justified 
use of the good cause exemption to bypass notice and comment and the 
30-day delayed effective date.
    The FAA notes the comment was submitted in response to an NPRM for 
which the FAA provided a 45-day comment period. This final rule is 
effective 35 days after its publication in the Federal Register. 
Therefore, the FAA did not change this AD as a result of this comment.

Requests To Reference Service Material and Clarify Compliance

    American Airlines, IndiGo, and Lufthansa Technik requested that the 
FAA revise the NPRM to reference IAE AG SB V2500-ENG-72-0716, dated 
October 4, 2024. SIAEC also requested that the FAA clarify if 
accomplishing the 3rd stage HPC rotor blades replacement in accordance 
with IAE AG SB V2500-ENG-72-0716, dated October 4, 2024, demonstrates 
compliance with the NPRM. American Airlines stated that the terminating 
action for the requirements of the NPRM is replacement of the 3rd stage 
HPC rotor blades using IAE AG SB V2500-ENG-72-0716, dated October 4, 
2024, but that material is not referenced anywhere in the NPRM. IndiGo 
specifically recommended revising paragraph (g) of the proposed AD to 
require replacing the 3rd stage HPC rotor blades in accordance with IAE 
AG SB V2500-ENG-72-0716, dated October 4, 2024.
    The FAA agrees to clarify that replacing the 3rd stage HPC rotor 
blades in accordance with IAE AG SB V2500-ENG-72-0716, dated October 4, 
2024, demonstrates compliance with the requirements of this AD because 
doing so changes the part numbers to those listed in the definition of 
``part eligible for installation'' in paragraph (h) of this AD. The FAA 
disagrees with the request to reference IAE AG SB V2500-ENG-72-0716, 
dated October 4, 2024, in this AD because this AD already provides the 
necessary compliance procedures. The FAA did not change this AD as a 
result of this comment.

Request To Make Incorporation by Reference (IBR) Materials Reasonably 
Available

    The Citizens Rulemaking Alliance requested that the FAA confirm 
that IBR materials are properly identified and reasonably available as 
required by 1 CFR 51.5 and 51.9. The commenter stated that if the 
preamble of the rule lacks the identification of the specific documents 
and revision levels, and reasonable availability for free inspection 
via the docket, the FAA office, and the National Archives and Records 
Administration, IBR should not be approved until this is corrected.
    The FAA notes that this AD does not IBR any material. Additionally, 
paragraph (k) of this AD specifies that there is no IBR in this AD. 
Therefore, the FAA did not change this AD as a result of this comment.

Request To Comply With the Paperwork Reduction Act (PRA)

    The Citizens Rulemaking Alliance requested that the FAA revise the 
proposed AD to comply with the PRA if reporting is required or remove 
any mandatory reporting provisions or suspend enforcement until PRA 
requirements are satisfied. If reporting is not required, the commenter 
requested the FAA clarify that in the AD.
    The FAA notes that this AD does not require reporting. If an AD 
were to require reporting, the preamble of the AD would include a 
paragraph titled ``Paperwork Reduction Act'' that would provide the 
applicable OMB control number, required PRA statements, and the 
estimated time to collect the required information (burden). Any costs 
associated with the reporting requirement would be included in the 
Costs of Compliance section in the preamble of the AD. Therefore, the 
FAA did not change this AD as a result of this comment.

Request To Add Cost Estimate for New Blades

    Lufthansa Technik requested that the FAA revise the estimated costs 
table of the NPRM to include the costs for a set of new blades. 
Lufthansa Technik stated that the table only includes costs for 
replacement with reworked blades, and this does not reflect actual 
modification costs because the blade rework is not an established 
alternative and new blades are more than five times the cost of 
reworked blades.
    The FAA partially agrees. The FAA disagrees with revising the 
Estimated Costs table in this final rule because the FAA predicts that 
most operators will choose the most cost-effective option of 
replacement with reworked blades. However, the FAA agrees that the cost 
of a full set of new blades should be mentioned in the Costs of 
Compliance section of this final rule because replacement with new 
blades is an acceptable option for compliance with this AD. Therefore, 
the FAA has revised the Costs of Compliance section of this final rule 
to include this estimate.

Request To Consider Impact on Small Entities

    The Citizens Rulemaking Alliance requested that the FAA either 
provide the factual basis for its Regulatory Flexibility Act (RFA) 
certification that the AD will not have a significant economic impact 
on a substantial number of small entities or prepare an initial 
regulatory flexibility analysis and solicit comment. The commenter 
stated that the FAA should disclose how many small U.S. carriers 
operate the affected engines, projected per-entity compliance costs 
(including labor and parts), and downtime or scheduling impacts caused 
by the proposed AD.
    The FAA has considered the AD's impact on small entities and 
provides the following factual basis for its RFA certification.
    The Regulatory Flexibility Act of 1980, Public Law 96-354, 94 Stat. 
1164 (5 U.S.C. 601-612), as amended by the Small Business Regulatory 
Enforcement Fairness Act of 1996 (Pub. L. 104-121, 110 Stat. 857, Mar. 
29, 1996) and the Small Business Jobs Act of 2010 (Pub. L. 111-240, 124 
Stat. 2504 Sept. 27, 2010), requires Federal agencies to consider the 
effects of the regulatory action on small business and other small 
entities and to minimize any significant economic impact. The term 
``small entities'' comprises small businesses and not-for-profit 
organizations that are independently owned and operated and are not 
dominant in their fields, and governmental jurisdictions with 
populations of less than 50,000.

Small Entities to Which This AD Applies

    The FAA used the definition of small entities in the RFA for this 
analysis. The RFA defines small entities as small businesses, small 
governmental jurisdictions, or small organizations. In 5 U.S.C. 601(3), 
the RFA defines ``small business'' to have the same meaning as ``small 
business concern'' under section 3 of the Small Business Act. The Small 
Business Act authorizes the Small Business Administration (SBA) to 
define ``small business'' by issuing regulations.
    The SBA has established size standards for various types of 
economic activities, or industries, under the North American Industry 
Classification System (NAICS). These size standards generally define 
small businesses based on the number of employees or annual receipts. 
The following table shows the SBA size standards for all industries 
with at least 1 impacted entity. Note that the SBA definition of a 
small

[[Page 53715]]

business applies to the parent company and all affiliates as a single 
entity.

                      Small Business Size Standards
------------------------------------------------------------------------
      NAICS code             Description             Size standard
------------------------------------------------------------------------
336413................  Other Aircraft Parts   1,250 employees.
                         and Auxiliary
                         Equipment
                         Manufacturing.
481111................  Scheduled Passenger    1,500 employees.
                         Air Transportation.
532411................  Commercial Air         $47,000,000.
                         Transportation
                         Equipment Rental and
                         Leasing.
------------------------------------------------------------------------

    To identify small entities, the FAA first identified the primary 
NAICS of the entity or parent company, and then used data from 
different sources (e.g., company annual reports, Bureau of 
Transportation Statistics) to determine whether the entity meets the 
applicable size standard. The following table provides a summary of the 
results.

                                       Estimated Number of Small Entities
----------------------------------------------------------------------------------------------------------------
                                                                                         Number of     Percent
                          Category                             Number of     Engines       small        small
                                                               entities                   entities     entities
----------------------------------------------------------------------------------------------------------------
Aircraft Manufacturing.....................................             1            6            0            0
Other Aircraft Parts and Auxiliary Equipment Manufacturing.             2            4            2          100
Scheduled Passenger Air Transportation.....................             8        1,398            1           13
Commercial Air Transportation Equipment Rental and Leasing.            12           54            5           42
                                                            ----------------------------------------------------
    Total..................................................            23        1,462            8           35
----------------------------------------------------------------------------------------------------------------

Projected Reporting, Recordkeeping, and Other Compliance Requirements

    The FAA estimates affected entities will incur a cost of $30,085 to 
replace a full set of 3rd stage HPC rotor blades with reworked blades. 
If the blades are unserviceable and cannot be reworked, the cost of a 
full set of new blades is estimated to be $225,000. The following table 
provides the estimated low-case cost and high-case cost by each NAICS 
industry.

                                   Average Cost of Compliance per Small Entity
----------------------------------------------------------------------------------------------------------------
                                                                     Low-case cost            High-case cost
                                                    Annual    --------------------------------------------------
                    Category                        revenue      Average    Percent of     Average    Percent of
                                                                  cost        revenue       cost       revenue
----------------------------------------------------------------------------------------------------------------
Other Aircraft Parts and Auxiliary Equipment       $2,750,000     $60,170          2.2     $450,000         16.4
 Manufacturing.................................
Scheduled Passenger Air Transportation.........   246,300,000     481,360          0.2    3,600,000          1.5
Commercial Air Transportation Equipment Rental      5,400,000     132,374          2.5      990,000         18.3
 and Leasing...................................
----------------------------------------------------------------------------------------------------------------

Significant Alternatives Considered

    The FAA evaluated the alternative of not promulgating this AD but 
ultimately deemed that this alternative would create a significant 
safety hazard. The FAA is issuing this AD to address the unsafe 
condition for certain 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, ensuring a level of safety that the alternative of no action 
could not provide.

Request To Provide Additional Cost Information

    The Citizens Rulemaking Alliance requested that the FAA provide an 
explicit Unfunded Mandates Reform Act (UMRA) determination and a more 
complete cost analysis. The commenter requested that the FAA provide 
the number of engines affected, inspection intervals, labor 
assumptions, expected finding rates, parts costs if findings occur, and 
the on-year aggregation method. Further, if the revised calculations 
approach or exceed the $100 million threshold under reasonable 
assumptions, the FAA should treat the action accordingly or separate 
non-urgent elements for standard rulemaking.
    The FAA notes that in the preamble of the proposed AD, the FAA 
certified that this regulation is not a ``significant regulatory 
action'' under Executive Order 12866 and will not have an annual effect 
on the economy of $100 million or more. Further, in the Costs of 
Compliance section of the NPRM, the FAA disclosed the number of 
affected engines on the U.S. registry and the number of work hours per 
affected engine to estimate the cost of the AD on all U.S. operators. 
The FAA also disclosed an estimated parts cost. Additionally, the FAA 
considered the impact that this AD will have on affected operators and 
determined this AD will not trigger any downtime costs or scheduling 
disruptions because the requirements of this AD can be performed during 
regularly scheduled maintenance. However, as previously discussed, the 
FAA has revised this final rule to include the cost of a full set of 
new blades. Since the FAA has assessed and disclosed the total known 
costs of the AD requirements in the Costs of Compliance section of the 
proposed AD with the addition of the replacement cost using a full set 
of new blades in this final rule, and because the commenter did not 
provide additional cost data for the FAA to consider in its cost 
analysis, it is not necessary to provide additional information in the

[[Page 53716]]

AD docket. The FAA did not change this AD as a result of this comment.

Request To Revise Compliance Language

    United Airlines requested that the FAA clarify the timeline for 
required actions by revising paragraph (g) of the proposed AD to state, 
``For any engine inducted into a shop visit after the effective date of 
this AD where 3rd stage rotor blade is exposed, replace the full set of 
3rd stage HPC rotor blades with parts eligible for installation.'' 
United Airlines noted that the exact exposure date can be difficult to 
track for engines inducted for a shop visit prior to the AD effective 
date, and revising the language would allow for easier tracking of when 
the AD would apply to a specific engine.
    The FAA agrees to revise paragraph (g) of this AD because 3rd stage 
HPC rotor blade replacement can only be performed at a shop visit and 
it is not the FAA's intent to require engines that were inducted into 
an engine shop visit prior to the effective date of this AD to comply 
with the AD. The FAA has also revised paragraph (h) of this AD by 
adding paragraph (h)(3) to include a definition for ``engine shop 
visit.''

Request for Alternative Method of Compliance Due to Parts Shortage

    Lufthansa Technik requested that the FAA revise the proposed AD to 
allow for repetitive inspections of 3rd stage HPC rotor blades as an 
alternative method of compliance for the required blade replacement. 
Lufthansa Technik stated that a shortage of parts eligible for 
installation is expected due to limited rework options.
    The FAA disagrees with the request. The FAA has received assurance 
from the parts original equipment manufacturer (OEM) that no parts 
shortages are expected due to limited rework options, and new hardware 
production has been increased to meet current demand. The OEM also 
informed the FAA that there are no inspections currently available for 
the 3rd stage HPC rotor blades to mitigate this issue. Therefore, the 
FAA will not mandate any repetitive inspections of the affected 3rd 
stage HPC rotor blades as an alternative to the blade replacements. If 
parts may not be available in a timely manner, paragraph (i)(1) of this 
AD allows operators to request approval of an alternative method of 
compliance to extend the compliance time, based on a showing that the 
extension will not adversely affect safety. The FAA did not change this 
AD as a result of this comment.

Conclusion

    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, and 
any other changes described previously, this AD is adopted as proposed 
in the NPRM.

Costs of Compliance

    The FAA estimates that this AD affects 1,462 engines installed on 
aircraft of U.S. registry.\1\ The FAA estimates the following costs to 
comply with this AD:
---------------------------------------------------------------------------

    \1\ The affected population may be smaller than indicated as 
some operators might already have accomplished IAE AG SB V2500-ENG-
72-0716, dated October 4, 2024.

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                       Cost per    Cost on U.S.
                  Action                           Labor cost *          Parts cost    product       operators
----------------------------------------------------------------------------------------------------------------
Replace full set of 3rd stage HPC rotor    1 work-hour x $85 per hour       $30,000      $30,085     $43,984,270
 blades with reworked blades.               = $85.
----------------------------------------------------------------------------------------------------------------
* The FAA estimated operators will incur $85 in costs per labor hour, which is the weighted average fiscal year
  (FY) 2026 fully loaded wage of an aircraft mechanic ($69.85) working 60% of the labor hours and a general and
  operations manager ($108.15) working 40% of the labor hours. The FAA estimated these wages by taking the
  average of the FY 2024 Bureau of Labor Statistics (BLS) air transportation industry average wage for aircraft
  mechanics and general and operations managers (See: Occupational Employment and Wage Statistics Query System,
  BLS (May 2024), data.bls.gov/oes/); multiplying each wage by a fringe benefit factor of 1.42 (See: Employer
  Cost for Employee Compensation--December 2024, BLS (2024), bls.gov/news.release/archives/ecec_03142025.pdf);
  and adjusting these 2024 wages to 2026 dollars using an implicit Gross Domestic Product (GDP) Price Deflator
  of 2.8% (See: Gross Domestic Product: Implicit Price Deflator, FRED (2026) fred.stlouisfed.org/series/GDPDEF).

    Although this AD provides two options for replacement, with new or 
reworked blades, the FAA predicts most operators will choose to replace 
with reworked blades, which is the most cost-effective option. If the 
blades are unserviceable and cannot be reworked, the cost of a full set 
of new blades is estimated to be $225,000.

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:

[[Page 53717]]

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:

2026-17-03 International Aero Engines AG: Amendment 39-23446; Docket 
No. FAA-2025-2555; Project Identifier AD-2025-00433-E.

(a) Effective Date

    This airworthiness directive (AD) is effective September 24, 
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 number (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 engine shop visit after the effective date of this 
AD where the 3rd stage HPC rotor is exposed, 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.
    (3) For the purpose of this AD, an ``engine shop visit'' is the 
induction of an engine into the shop for maintenance.

(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: [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.

(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: [email protected].

(k) Material Incorporated by Reference

    None.

    Issued on August 17, 2026.
Brian Knaup,
Acting Deputy Director, Integrated Certificate Management Division, 
Aircraft Certification Service.
[FR Doc. 2026-16954 Filed 8-19-26; 8:45 am]
BILLING CODE 4910-13-P