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Rule2026-21590

Airworthiness Directives; General Electric Company Engines

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Published
October 22, 2026
Effective
November 27, 2026

Issuing agencies

Transportation DepartmentFederal Aviation Administration

Abstract

The FAA is adopting a new airworthiness directive (AD) for certain General Electric Company (GE) Model CF34-8C1, CF34-8C5, CF34- 8C5A1, CF34-8C5A2, CF34-8C5B1, CF34-8E2, CF34-8E2A1, CF34-8E5, CF34- 8E5A1, CF34-8E5A2, CF34-8E5A2HA, CF34-8E6, and CF34-8E6A1 engines. This AD was prompted by reports of in-flight "Engine Degraded" messages from the engine indicating and crew alerting system (EICAS) due to corrosion of the variable geometry (VG) system actuator. This AD requires removing certain electronic engine control (EEC) full authority digital electronic control (FADEC) software versions from service and installing an updated EEC FADEC software that is eligible for installation. The FAA is issuing this AD to address the unsafe condition on these products.

Full Text

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<title>Federal Register, Volume 91 Issue 203 (Thursday, October 22, 2026)</title>
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[Federal Register Volume 91, Number 203 (Thursday, October 22, 2026)]
[Rules and Regulations]
[Pages 66631-66635]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-21590]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-3998; Project Identifier AD-2025-00432-E; 
Amendment 39-23500; AD 2026-21-11]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain General Electric Company (GE) Model CF34-8C1, CF34-8C5, CF34-
8C5A1, CF34-8C5A2, CF34-8C5B1, CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-
8E5A1, CF34-8E5A2, CF34-8E5A2HA, CF34-8E6, and CF34-8E6A1 engines. This 
AD was prompted by reports of in-flight ``Engine Degraded'' messages 
from the engine indicating and crew alerting system (EICAS) due to 
corrosion of the variable geometry (VG) system actuator. This AD 
requires removing certain electronic engine control (EEC) full 
authority digital electronic control (FADEC) software versions from 
service and installing an updated EEC FADEC software that is eligible 
for installation. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective November 27, 2026.

ADDRESSES: 
    AD Docket: You may examine the AD docket at <a href="http://regulations.gov">regulations.gov</a> under 
Docket No. FAA-2025-3998; 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: Daiyun Fang, Aviation Safety Engineer, 
FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (206) 910-
0063; email: <a href="/cdn-cgi/l/email-protection#95f1f4fcece0fbbbf3f4fbf2d5f3f4f4bbf2fae3"><span class="__cf_email__" data-cfemail="ee8a8f87979b80c0888f8089ae888f8fc0898198">[email&#160;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 certain GE Model CF34-
8C1, CF34-8C5, CF34-8C5A1, CF34-8C5A2, CF34-8C5B1, CF34-8E2, CF34-
8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E5A2HA, CF34-8E6, and 
CF34-8E6A1 engines. The NPRM was published in the Federal Register on 
November 18, 2025 (90 FR 51590). The NPRM was prompted by three 
separate events involving airplanes with Model GE CF34-8C5 engines 
installed in which ``Engine Degraded'' messages were received from the 
EICAS during flight. A subsequent investigation by the manufacturer 
revealed that these engines had been operated infrequently over the 
two-year period prior to these events and stored in close proximity to 
a saltwater coastline. The investigation further revealed the VG 
actuation lever arms were stuck due to corrosion between the high-
pressure compressor case and vane bushings, which increased the VG 
actuation loads and slowed the VG response. As a result of this 
increase, the VG command and actual positions exceeded acceptable 
disagreement parameters, triggering an EICAS ``Engine Degraded'' 
message. In response to the ``Engine Degraded'' message, the 
manufacturer and FAA determined that certain versions of the EEC FADEC 
software installed on GE Model CF34-8E and CF34-8C engines can 
potentially reduce the engine to idle and lock the throttle until the 
engine is shut down and restarted. In the NPRM, the FAA proposed to 
require removal of certain EEC FADEC software versions from service and 
installation of updated EEC FADEC software that is 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 three commenters. The commenters 
were the Airline Pilots Association, International (ALPA), the Citizens 
Rulemaking Alliance, and Horizon Air. The following presents the 
comments received on the NPRM and the FAA's response to each comment.

Support for the NPRM

    ALPA expressed support for the NPRM.

Request To Justify Forgoing Notice and Comment or Issue an NPRM

    The Citizens Rulemaking Alliance requested that the FAA place a 
detailed analysis in the AD docket explaining why prior notice and 
comment were impracticable for each requirement and why the selected 
compliance times necessitated immediate issuance. Alternatively, the 
commenter requested that the FAA either convert this action to an 
interim final rule limited to actions necessary to mitigate any 
immediate risk and simultaneously issue an NPRM to solicit comment for 
30 to 60 days on non-emergency actions. The commenter asserted the FAA 
has not adequately justified use of the good cause exception to bypass 
notice and comment and the 30-day delayed

[[Page 66632]]

effective date and must, at a minimum, provide an explanation why a 
brief comment period was impracticable.
    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.

Request To Comply With the Paperwork Reduction Act (PRA)

    The Citizens Rulemaking Alliance requested that the FAA clarify 
whether the proposed AD requires reporting. If reporting is required, 
the commenter requested that the FAA revise the proposed AD to comply 
with the PRA or suspend the reporting requirement until PRA 
requirements are satisfied.
    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 Make Incorporation by Reference (IBR) Materials Reasonably 
Available

    The Citizens Rulemaking Alliance stated that the FAA's current 
practices for IBR frequently fail to meet the legal and regulatory 
standards for reasonable availability. The commenter called on the FAA 
to guarantee that all IBR materials are easily and freely accessible to 
the public and affected parties for both commenting and compliance 
purposes. The commenter requested that the IBR materials be identified 
in the proposed AD along with a detailed summary and a statement 
confirming the reasonable availability of the materials. Further, the 
commenter requested that the required IBR materials be placed in the AD 
docket or that the FAA ensure free online access for the duration of 
the comment period and applicability of the AD.
    The FAA notes that this AD does not incorporate by reference any 
material. All required actions and compliance times are contained 
within the regulatory text of this AD. Additionally, paragraph (j) of 
this AD specifies that there is no IBR material in this AD. Therefore, 
the FAA did not change this AD as a result of this comment.

Request To Provide Additional Cost Information

    The Citizens Rulemaking Alliance requested that the FAA clarify its 
cost estimate for determining the proposed AD is not significant under 
Executive Order 12866. The commenter stated the FAA should publish the 
number of affected U.S. products and costs per product (labor rate, 
labor hours, parts, downtime, and number of affected engines/aircraft). 
The commenter requested that any safety benefit quantification or 
break-even analysis that might have been performed along with the other 
cost information be placed in the AD docket and comments invited.
    In the Costs of Compliance section of the proposed AD, the FAA 
disclosed the number of affected engines installed on airplanes on the 
U.S. registry, estimated number of work hours and parts cost provided 
by the manufacturer, and the aggregate costs. Additionally, the FAA 
considered the impact that this AD will have on affected operators and 
determined this AD will not trigger any downtime costs because the 
requirements of this AD can be performed during regularly scheduled 
maintenance. Since the FAA has assessed and disclosed the total known 
costs of the AD requirements in the Costs of Compliance section of the 
NPRM, and 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 AD docket. Based upon the analysis 
provided throughout the proposed AD and in the previous comment 
response, the FAA certifies that this AD is not a ``significant 
regulatory action'' under Executive Order 12866. Therefore, the FAA did 
not change this AD as a result of this comment.

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 a detailed initial 
regulatory flexibility analysis that quantifies direct and indirect 
costs (including parts and downtime) and assesses significant 
alternatives (longer compliance times for low-utilization small 
operators, tiered inspection intervals, on-condition monitoring, 
streamlined alternative method of compliance pathways) for small 
entities.
    The FAA has considered the AD's impact on small businesses and 
provides the following factual basis for its RFA certification.

Final Regulatory Flexibility Analysis

    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 provides the SBA size standards for all industries 
with at least one entity impacted by this AD.\1\ Note that the SBA 
definition of a small business applies to the parent company and all 
affiliates as a single entity.
---------------------------------------------------------------------------

    \1\ FAA was unable to obtain data to identify the NAICS code of 
four entities.

[[Page 66633]]



                  Description of Small Entity Standards
------------------------------------------------------------------------
       NAICS code            Description            Size standard
------------------------------------------------------------------------
325180.................  Other Basic         1,000 employees.
                          Inorganic
                          Chemical
                          Manufacturing.
336411.................  Aircraft            1,500 employees.
                          Manufacturing.
481111.................  Scheduled           1,500 employees.
                          Passenger Air
                          Transportation.
481219.................  Other Nonscheduled  $22,000,000.
                          Air
                          Transportation.
488119.................  Other Airport       $35,000,000.
                          Operations.
532490.................  Other Commercial    $35,000,000.
                          and Industrial
                          Machinery and
                          Equipment Rental
                          and Leasing.
551112.................  Offices of Other    $40,000,000.
                          Holding Companies.
711211.................  Sports Teams and    $41,500,000.
                          Clubs.
713940.................  Fitness and         $15,500,000.
                          Recreational
                          Sports Centers.
------------------------------------------------------------------------

    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 FAA provides the estimated number of 
small entities affected by this AD:

                                Number and Percent of Entities That Are Small \1\
----------------------------------------------------------------------------------------------------------------
                                                                               Number of  Percent of    Engines
         NAICS code                  Category          Number of    Affected     small       small     for small
                                                        entities    engines    entities    entities    entities
----------------------------------------------------------------------------------------------------------------
325180......................  Other Basic Inorganic             1          4           1         100           4
                               Chemical
                               Manufacturing.
336411......................  Aircraft Manufacturing            2          8           0           0           0
481111......................  Scheduled Passenger              10      3,270           2          20         132
                               Air Transportation.
481219......................  Other Nonscheduled Air            1          2           1         100           2
                               Transportation.
488119......................  Other Airport                     1          4           1         100           4
                               Operations.
532490......................  Other Commercial and              1         34           0           0           0
                               Industrial Machinery
                               and Equipment Rental
                               and Leasing.
551112......................  Offices of Other                  1         20           0           0           0
                               Holding Companies.
711211......................  Sports Teams and Clubs            1          4           1         100           4
713940......................  Fitness and                       1          8           0           0           0
                               Recreational Sports
                               Centers.
----------------------------------------------------------------------------------------------------------------
\1\ Entities whose NAICS code was not identified as well as entities that are not considered ``small'' under the
  RFA are not included in this table.

Projected Reporting, Recordkeeping, and Other Compliance Requirements

    As described in the Cost of Compliance section of this final rule, 
it will cost $1,340 to remove and install affected versions of software 
with updated versions for each affected engine. For the purpose of this 
analysis, each aircraft is assumed to have two engines, bringing the 
cost per aircraft to $2,680 to remove and install the software. This is 
described here as the ``low case''. In addition, 70 engines will 
require a memory upgrade, which costs $49,680, in addition to the 
$1,340 to remove and install software, for a total of $51,020. This is 
described as the ``high case''. The costs faced by each entity are 
given in the following table. Three of the six identified small 
entities face impacts greater than 2 percent of their annual revenues.

                                            Impacts on Small Entities
----------------------------------------------------------------------------------------------------------------
                                                                       Low case                 High case
                                                    Average   --------------------------------------------------
        NAICS code            NAICS description     revenues     Average    Percent of     Average    Percent of
                                                                  cost      revenue \1\     cost     revenue \1\
----------------------------------------------------------------------------------------------------------------
325180....................  Other Basic            $6,780,000      $5,360         0.08     $104,720         1.54
                             Inorganic Chemical
                             Manufacturing.
481111....................  Scheduled Passenger    42,005,000      88,440         0.17    1,727,880         3.30
                             Air Transportation.
481219....................  Other Nonscheduled        348,870       2,680         0.77       52,360        15.01
                             Air Transportation.
488119....................  Other Airport           3,900,000       5,360         0.14      104,720         2.69
                             Operations.
711211....................  Sports Teams and       21,270,000       5,360         0.03      104,720         0.49
                             Clubs.
----------------------------------------------------------------------------------------------------------------
\1\ Value obtained by, for each NAICS Code, dividing each firm's cost by that firm's annual revenue, and
  averaging the result. This estimate is more precise than dividing the average cost among all entities by the
  average revenue of all entities within a NAICS Code.

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. This AD was prompted by reports of in-flight ``Engine 
Degraded'' messages from the EICAS due to corrosion of the VG system 
actuator. This AD requires removing certain EEC FADEC software versions 
from service and installing updated EEC FADEC software that is eligible 
for installation. The FAA is issuing this AD to address the unsafe 
condition on these products.

Request To Include Service Material

    Horizon Air requested that the FAA revise paragraph (j) of the 
proposed AD to include reference to GE CF34-8E Service Bulletin (SB) 
73-0044, dated July 4, 2025 (GE SB 73-0044, dated July 4, 2025), to 
provide additional guidance for updating the EEC FADEC software.

[[Page 66634]]

Horizon Air stated that previously published FAA ADs requiring EEC 
FADEC software updates included reference to the manufacturer's service 
bulletin that contains accomplishment instructions for the replacement 
of the FADEC software version with a version eligible for installation. 
Horizon Air also noted that GE SB 73-0044, dated July 4, 2025, contains 
a statement from GE authorizing the FAA to incorporate the document by 
reference in an AD.
    The FAA disagrees with the request to add guidance documentation to 
paragraph (j) of this AD because the instructions provided in GE SB 73-
0044, dated July 4, 2025, are not required to comply with this AD. 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, 
replacement of the RFA certification with a final regulatory 
flexibility analysis, and a change in the Costs of Compliance section 
(from 3,040 engines to 3,364 engines and corresponding cost changes), 
this AD is adopted as proposed in the NPRM. None of the changes will 
increase the economic burden on any operator.

Costs of Compliance

    The FAA estimates that this AD affects 3,364 engines installed on 
airplanes of U.S. registry. The FAA estimates that 70 of these affected 
engines will also require an additional memory upgrade of the EEC FADEC 
software from a three memory sector configuration to a seven memory 
sector configuration.

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                       Cost per    Cost on U.S.
                  Action                          Labor cost \1\         Parts cost    product       operators
----------------------------------------------------------------------------------------------------------------
Remove and install EEC FADEC software....  8 work-hours x $85 per hour         $660       $1,340      $4,507,760
                                            = $680.
Upgrade EEC FADEC software to seven        8 work-hours x $85 per hour       49,000       49,680       3,477,600
 sectors (70 engines).                      = $680.
----------------------------------------------------------------------------------------------------------------
\1\ 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 percent of the labor hours and a
  general and operations manager ($108.15) working 40 percent 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), <a href="http://data.bls.gov/oes/">data.bls.gov/oes/</a>); multiplying each wage by a fringe benefit factor of 1.42
  (See: Employer Cost for Employee Compensation--December 2024, BLS (2024), <a href="http://bls.gov/news.release/archives/ecec_03142025.pdf">bls.gov/news.release/archives/ecec_03142025.pdf</a>); and adjusting these 2024 wages to 2026 dollars using an implicit Gross Domestic Product
  (GDP) Price Deflator of 2.8 percent (See: Gross Domestic Product: Implicit Price Deflator, FRED (2026)
  <a href="http://fred.stlouisfed.org/series/GDPDEF">fred.stlouisfed.org/series/GDPDEF</a>).

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:

2026-21-11 General Electric Company: Amendment 39-23500; Docket No. 
FAA-2025-3998; Project Identifier AD-2025-00432-E.

(a) Effective Date

    This airworthiness directive (AD) is effective November 27, 
2026.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to the General Electric Company (GE) Model 
engines identified in paragraphs (c)(1) and (2) of this AD.
    (1) CF34-8C1, CF34-8C5, CF34-8C5A1, CF34-8C5A2, and CF34-8C5B1 
engines with an electronic engine control (EEC) full authority 
digital electronic control (FADEC) part number (P/N) 4120T00P29, 
4120T00P30, 4120T00P37, 4120T00P38, 4120T00P45, 4120T00P46, 
4120T00P53, 4120T00P54, 4120T00P57, or 4120T00P58 installed.
    (2) CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, 
CF34-8E5A2HA, CF34-8E6, and CF34-8E6A1 engines with an EEC FADEC P/N 
4120T00P42 (VIN 111E9320G43), P/N 4120T00P44 (VIN 111E9320G45), P/N 
4120T00P48 (VIN 111E9320G49), P/N 4120T00P50 (VIN 111E9320G51), or 
P/N 4120T00P60 (VIN 111E9320G61) installed.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7230, Turbine Engine 
Compressor Section.

[[Page 66635]]

(e) Unsafe Condition

    This AD was prompted by an ``Engine Degraded'' message received 
in-flight from the engine indicating and crew alerting system, due 
to corrosion of the variable geometry system actuator. The FAA is 
issuing this AD to prevent EEC FADEC software from automatically 
locking the engine at idle until it is restarted. The unsafe 
condition, if not addressed, could result in failure of one or more 
engines, loss of engine thrust control, and consequent reduced 
control of the airplane.

(f) Compliance

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

(g) Definitions

    For the purpose of this AD:
    (1) ``Group 1 engines'' are GE Model CF34-8C1, CF34-8C5, CF34-
8C5A1, CF34-8C5A2, and CF34-8C5B1 engines.
    (2) ``Group 2 engines'' are GE Model CF34-8E2, CF34-8E2A1, CF34-
8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E5A2HA, CF34-8E6, and CF34-8E6A1 
engines.
    (3) An ``EEC FADEC software version that is eligible for 
installation'' on Group 1 engines is any software version that is 
V6.60 or later approved version.
    (4) An ``EEC FADEC software version that is eligible for 
installation'' on Group 2 engines is any software version that is 
V5.70 or later approved version.

(h) Required Actions

    (1) For Group 1 engines, within 12 months after the effective 
date of this AD, replace any EEC FADEC software version that is 
V6.50 or earlier with an EEC FADEC software version that is eligible 
for installation.
    (2) For Group 2 engines, within 12 months after the effective 
date of this AD, replace any EEC FADEC software version that is 
V5.60 or earlier with an EEC FADEC software version that is eligible 
for installation.

(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 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#cf8e82808c8fa9aeaee1a8a0b9"><span class="__cf_email__" data-cfemail="db9a9694989bbdbabaf5bcb4ad">[email&#160;protected]</span></a>.
    (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 Daiyun Fang, 
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, 
WA 98198; phone: (206) 910-0063; email: <a href="/cdn-cgi/l/email-protection#aacecbc3d3dfc484cccbc4cdeacccbcb84cdc5dc"><span class="__cf_email__" data-cfemail="f490959d8d819ada92959a93b4929595da939b82">[email&#160;protected]</span></a>.

(k) Material Incorporated by Reference

    None.

    Issued on October 19, 2026.
Brian Knaup,
Acting Deputy Director, Integrated Certificate Management Division, 
Aircraft Certification Service.
[FR Doc. 2026-21590 Filed 10-21-26; 8:45 am]
BILLING CODE 4910-13-P


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