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[Federal Register Volume 90, Number 5 (Wednesday, January 8, 2025)]
[Rules and Regulations]
[Pages 1361-1365]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-00208]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-0755; Project Identifier AD-2023-00521-E; 
Amendment 39-22909; AD 2024-25-07]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain General Electric Company (GE) Model GEnx-1B64, GEnx-1B64/P1, 
GEnx-1B64/P2, GEnx-1B67, GEnx-1B67/P1, GEnx-1B67/P2, GEnx-1B70, GEnx-
1B70/75/P1, GEnx-1B70/75/P2, GEnx-1B70/P1, GEnx-1B70/P2, GEnx-1B70C/P1, 
GEnx-1B70C/P2, GEnx-1B74/75/P1, GEnx-1B74/75/P2, GEnx-1B76/P2, GEnx-
1B76A/P2, GEnx-2B67, GEnx-2B67B, and GEnx-2B67/P engines. This AD was 
prompted by a manufacturer evaluation that determined a lower life 
limit may be necessary for certain stages 6-10 compressor rotor spools 
than allowed by the engine shop manual (ESM). This AD requires a one-
time inspection of the stages 6-10 spools for previously accomplished 
blend repairs, a one-time inspection of the blend repairs on the stages 
6-10 spools for compliance with the updated allowable limits, and 
replacement if necessary. The FAA is issuing this AD to address the 
unsafe condition on these products.

DATES: This AD is effective February 12, 2025.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of February 12, 
2025.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2024-0755; 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.
    Material Incorporated by Reference:
     For GE material identified in this AD, contact GE, 1 
Neumann Way, Cincinnati, OH 45215; phone: (513)

[[Page 1362]]

552-3272; email: ge.com">aviation.fleetsupport@ge.com; website: ge.com.
     You may view this material at the FAA, Airworthiness 
Products Section, 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-2024-0755.

FOR FURTHER INFORMATION CONTACT: Alexei Marqueen, Aviation Safety 
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: 
(781) 238-7178; 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 GE Model GEnx-
1B64/P1, GEnx-1B64/P2, GEnx-1B67, GEnx-1B67/P1, GEnx-1B67/P2, GEnx-
1B70, GEnx-1B70/75/P1, GEnx-1B70/75/P2, GEnx-1B70/P1, GEnx-1B70/P2, 
GEnx-1B70C/P1, GEnx-1B70C/P2, GEnx-1B74/75/P1, GEnx-1B74/75/P2, GEnx-
1B76/P2, GEnx-1B76A/P2, GEnx-2B67, GEnx-2B67B, and GEnx-2B67/P engines 
with certain stages 6-10 spool installed. The NPRM published in the 
Federal Register on March 25, 2024 (89 FR 20553). The NPRM was prompted 
by a manufacturer evaluation which determined that a lower life limit 
may be necessary for certain stages 6-10 spools than that allowed in 
the engine shop manual. In the NPRM, the FAA proposed to require 
accomplishing a one-time inspection of the stages 6-10 spools for 
previously accomplished blend repairs, a one-time inspection of the 
blend repairs on the stages 6-10 spools for compliance with the updated 
allowable limits, and replacement, if necessary, within compliance 
times specified in GE GEnx-1B Service Bulletin 72-0525, R00, dated 
October 4, 2023 (GEnx-1B SB 72-0525, R00), or GEnx-2B Service Bulletin 
72-0460, R00, dated October 4, 2023 (GEnx-2B SB 72-0460, R00). 
Depending on the part numbers and serial numbers of the affected stages 
6-10 spools, the NPRM proposed to require these actions to be 
accomplished at the next piece-part exposure after the effective date 
of the proposed AD, or before the affected stages 6-10 spool reaches 
the cyclic removal threshold of up to 11,894 cycles since new. 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 eight commenters. The commenters 
were American Airlines, Air Line Pilots Association, International 
(ALPA), Boeing Commercial Airplanes (Boeing), GE, Japan Airlines, Qatar 
Airways, United Airlines, and United Parcel Service (UPS). ALPA and 
Boeing supported the NPRM without change. The following presents the 
comments received on the NPRM and the FAA's response to each comment.

Request for Clarification of Compliance Time

    Qatar Airways requested clarification of the compliance threshold 
specified in the NPRM. The commenter pointed out that the compliance 
thresholds in the service information specify that ``at the next piece-
part exposure of the affected 6-10 spools, but before the affected 6-10 
spools reach the cycle since new threshold for inspection listed in 
paragraph 4., Appendix--A, Table 1,'' whereas the NPRM expressed the 
compliance time as ``At the next piece-part exposure after the 
effective date of this AD or before the affected stages 6-10 spool 
reaches the cyclic removal threshold specified in paragraph 4., 
Appendix-A, Table 1 of GEnx-1B 72-0525, R00 or GEnx-2B SB 72-0460, R00, 
as applicable.'' The commentor stated that the compliance time as 
written, is unclear about when to take action and which takes priority 
(next piece part or cycle thresholds).
    The FAA agrees that the compliance time is unclear. Paragraph (g) 
of this AD has been updated to state that the required action is to be 
performed at next piece part exposure or before the spool reaches the 
cycle removal thresholds, whichever occurs first.

Request To Update the Definition of ``Part Eligible for Installation''

    American Airlines and UPS requested that the FAA reword paragraph 
(h)(2) of the proposed AD to allow installation of an affected part, 
provided that the part passes the required inspections. UPS pointed out 
that in both paragraph (g) of the proposed AD and the service 
information, replacement of an affected part is only required if a 
previously accomplished blend repair is found and is also not within 
the allowable limits. However, the proposed definition would prohibit 
installation of any affected part, regardless of the inspection 
results. In addition, UPS requested that paragraph (h)(2) of the 
proposed AD be reworded to redefine a ``part eligible for 
installation'' as a stages 6-10 spool that does not have a P/N and S/N 
defined in paragraph 4, Appendix A, Table 1 of GEnx-1B 72-0525, R00 or 
GEnx-2B 72-0460, R00, or a stages 6-10 spool with a P/N and S/N that is 
listed in paragraph 4, Appendix A, Table 1 of GEnx-1B 72-0525, R00 or 
GEnx-2B 72-0460 that has been inspected and found to be within the 
allowable limits.
    The FAA agrees that a stages 6-10 spool that passes inspection does 
not need to be removed from service. Therefore, paragraph (h)(2) of 
this AD has been updated to reflect this change.

Request To Revise the Summary

    GE requested that the FAA revise the SUMMARY of the NPRM to clarify 
that for certain stages 6-10 compressor rotor spools there is a 
potential life shortfall to that specified in the ESM, instead of an 
absolute or definite life shortfall. GE stated that the evaluation of 
the repair limits demonstrated that at the worst size and location a 
stages 6-10 spool would have an ultimate life lower than that published 
in the ESM. However, there is no evidence to show that any of the 
affected stages 6-10 spools have a repair at the worst size and 
location. GE pointed out that for this reason, an inspection is 
required to determine if there is a possibility of the ultimate life 
lower than that published in the ESM. GE recommended adding the terms 
``may be'' to the SUMMARY to clarify that not all stages 6-10 spools 
will have a lower life limit.
    The FAA agrees that clarification is necessary and has updated the 
SUMMARY of this AD accordingly.

Request To Update the Required Service Information

    GE requested that the FAA update the NPRM to specify the latest 
revision of the service information. GE specified the intention to 
revise GE GEnx-1B SB 72-0525, R00 and GEnx-2B SB 72-0460, R00, and 
added that the updated revisions will not change actions or 
accomplishment instructions but will add wording indicating hardware 
that meets current ESM limits will not have a lower limit than 
published in CH05.
    The FAA agrees and has revised this AD to refer to GE GEnx-1B 
Service Bulletin 72-0525, R01, dated June 10, 2024 (GEnx-1B SB 72-0525, 
R01), and GEnx-2B Service Bulletin 72-0460, R01, dated June 10, 2024 
(GEnx-2B SB 72-0460, R01), as the appropriate source of service 
information. Additionally, the FAA has updated this AD to include 
credit for the actions required by paragraph (g) of this AD, if those 
actions were done prior to the effective date of

[[Page 1363]]

this AD using GE GEnx-1B SB 72-0525, R00 and GEnx-2B SB 72-0460, R00.

Request To Clarify the Applicability of ESM Life Limits

    United Airlines requested that the FAA include additional verbiage 
in the service information and the proposed AD that, in the case of an 
affected part passing the inspection, that part retains the ultimate 
life limit specified in the ESM. United Airlines stated that paragraph 
(g) of the proposed AD was not specific about what actions to take if 
the affected part passed the inspection. However, the service 
information specifies that no further action is necessary. Also, 
paragraph 1.E.(3) of GEnx-1B SB 72-0525, R00 and GEnx-2B SB 72-0460, 
R00 states that ``affected 6-10 spools were found to have life limit 
lower than ultimate life limit.''
    The FAA disagrees with the request. The life limits listed in the 
ESM are mandatory and applicable regardless of the actions required by 
this AD. Should any affected part be found to have a blend repair that 
is not in compliance with the allowable limits specified in the 
applicable service information, then this AD requires removal from 
service and replacement of that specific part. However, this AD does 
not change the life limits of parts that pass the inspection. 
Therefore, the FAA has not changed this AD in this regard.

Request To Specify the Affected Engine Models in the Required Actions

    Japan Airlines requested that the FAA revise paragraph (g) of the 
proposed AD to specify the affected engine models at the beginning of 
each of the sentences, to provide better clarity. Japan Airlines 
referred to paragraph (g) of AD 2023-17-08 as an example.
    The FAA disagrees with the request. AD 2023-17-08 specifies 
multiple affected parts on both the GEnx-1B and GEnx-2B Model engines, 
and therefore the FAA used multiple paragraphs for each affected part 
and each engine model. In this AD, the only affected parts are stages 
6-10 spools, making it unnecessary to specify engine models in 
paragraph (g) of this AD.

Changes After the NPRM Was Published

    After the NPRM was published, the FAA determined that Model GEnx-
1B64 engines were inadvertently left out of the applicability. None of 
these engines with the affected stages 6-10 spools are installed on 
airplanes on the U.S. registry. This model has been added to the 
applicability of the final rule in case one of these engines with 
affected 6-10 spools are installed on an airplane registered for 
operation in United States. Adding this model to the applicability does 
not increase the burden to U.S. operators over the already proposed 
requirements, so issuing a supplemental notice of proposed rulemaking 
is unnecessary.

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. None of the changes will increase the economic burden on 
any operator.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed GE GEnx-1B SB 72-0525, R01, and GEnx-2B SB 72-
0460, R01. This service information identifies the part numbers and 
serial numbers of affected stages 6-10 spools; and specifies 
instructions for a one-time inspection of the stages 6-10 spools for 
previously accomplished blend repairs, a one-time inspection of the 
blend repairs on the stages 6-10 spools for compliance with the updated 
allowable limits, and replacement if necessary. These documents are 
distinct since they apply to different engine models.
    This service information is reasonably available because the 
interested parties have access to it through their normal course of 
business or by the means identified in ADDRESSES section.

Costs of Compliance

    The FAA estimates that this AD affects 6 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
----------------------------------------------------------------------------------------------------------------
Inspect stages 6-10 spools............  8 work-hours x $85 per                $0            $680          $4,080
                                         hour = $680.
Inspect previous blend repairs........  1 work-hours x $85 per                 0              85             510
                                         hour = $85.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary 
replacements that would be required based on the results of the 
inspections. The agency has no way of determining the number of engines 
that might need this replacement:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace stages 6-10 spool.....................  8 work-hours x $85 per hour =         $1,307,600      $1,308,280
                                                 $680.
----------------------------------------------------------------------------------------------------------------

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

[[Page 1364]]

procedures the Administrator finds necessary for safety in air 
commerce. This regulation is within the scope of that authority because 
it addresses an unsafe condition that is likely to exist or develop on 
products identified in this rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, and
    (3) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.

Sec.  39.13   [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2024-25-07 General Electric Company: Amendment 39-22909; Docket No. 
FAA-2024-0755; Project Identifier AD-2023-00521-E.

 (a) Effective Date

    This airworthiness directive (AD) is effective February 12, 
2025.

 (b) Affected ADs

    None.

 (c) Applicability

    This AD applies to General Electric Company (GE) Model GEnx-
1B64, GEnx-1B64/P1, GEnx-1B64/P2, GEnx-1B67, GEnx-1B67/P1, GEnx-
1B67/P2, GEnx-1B70, GEnx-1B70/75/P1, GEnx-1B70/75/P2, GEnx-1B70/P1, 
GEnx-1B70/P2, GEnx-1B70C/P1, GEnx-1B70C/P2, GEnx-1B74/75/P1, GEnx-
1B74/75/P2, GEnx-1B76/P2, GEnx-1B76A/P2, GEnx-2B67, GEnx-2B67B, and 
GEnx-2B67/P engines with an installed:
    (1) Stages 6-10 compressor rotor spool (stages 6-10 spool) 
having a part number (P/N) and serial number (S/N) listed in 
paragraph 4, Appendix--A, Table 1 of GE GEnx-1B Service Bulletin 72-
0525, R01, dated June 10, 2024 (GEnx-1B SB 72-0525, R01); or
    (2) Stages 6-10 spool having a P/N and S/N listed in paragraph 
4, Appendix--A, Table 1 of GE GEnx-2B Service Bulletin 72-0460, R01, 
dated June 10, 2024 (GEnx-2B SB 72-0460, R01).

 (d) Subject

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

 (e) Unsafe Condition

    This AD was prompted by a manufacturer evaluation which 
determined that a lower life limit may be necessary for certain 
stages 6-10 spools than that allowed in the engine shop manual. The 
FAA is issuing this AD to prevent fracture and potential uncontained 
failure of the stages 6-10 spools. The unsafe condition, if not 
addressed, could result in uncontained debris release, damage to the 
engine, and damage to the aircraft.

 (f) Compliance

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

 (g) Required Actions

    At the next piece-part exposure after the effective date of this 
AD or before the affected stages 6-10 spool reaches the cyclic 
removal threshold specified in paragraph 4., Appendix--A, Table 1 of 
GEnx-1B 72-0525, R01 or GEnx-2B SB 72-0460, R01, as applicable, 
whichever occurs first, do the following actions:
    (1) Inspect the stages 6-10 spool for previously accomplished 
blend repairs in accordance with the Accomplishment Instructions, 
paragraph 3.B.(1) of GEnx-1B SB 72-0525, R01 or GEnx-2B SB 72-0460, 
R01, as applicable.
    (2) If during any inspection required by paragraph (g)(1) of 
this AD, any stages 6-10 spool is found to have a previously 
accomplished blend repair, before further flight, inspect the blend 
repair for compliance with the allowable limits in accordance with 
the Accomplishment Instructions, paragraph 3.B.(2) of GEnx-1B SB 72-
0525, R01 or GEnx-2B SB 72-0460, R01, as applicable.
    (3) If during any inspection required by paragraph (g)(2) of 
this AD, any stages 6-10 spool is found to have a previously 
accomplished blend repair that is not within the allowable limits, 
before further flight, remove the stages 6-10 spool from service and 
replace with a part eligible for installation in accordance with the 
Accomplishment Instructions, paragraph 3.B.(2)(a)1 or 3.B.(2)(b)1 of 
GEnx-1B SB 72-0525, R01 or GEnx-2B SB 72-0460, R01, as applicable.

 (h) Definition

    For the purposes of this AD:
    (1) A ``piece-part exposure'' is when the stages 6-10 spool is 
disassembled from the high-pressure compressor rotor assembly.
    (2) A ``part eligible for installation'' is either a stages 6-10 
spool that does not have a P/N and S/N identified in paragraph 4, 
Appendix--A, Table 1 of GEnx-1B 72-0525, R01 or GEnx-2B 72-0460, 
R01, or a stages 6-10 spool that does have a P/N and S/N identified 
in paragraph 4, Appendix--A, Table 1 of GEnx-1B 72-0525, R01 or 
GEnx-2B 72-0460, R01, provided that the affected part is not removed 
in accordance with paragraph (g)(3) of this AD.

 (i) Credit for Previous Actions

    You may take credit for the actions required by paragraph (g) of 
this AD if you performed those actions before the effective date of 
this AD using GE GEnx-1B Service Bulletin 72-0525, R00, dated 
October 4, 2023, or GEnx-2B Service Bulletin 72-0460, R00, dated 
October 4, 2023.

 (j) 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 (k) 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.

 (k) Related Information

    For more information about this AD, contact Alexei Marqueen, 
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, 
WA 98198; phone: (781) 238-7178; email: [email protected].

 (l) 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) GE GEnx-1B Service Bulletin 72-0525, R01, dated June 10, 
2024.
    (ii) GE GEnx-2B Service Bulletin 72-0460, R01, dated June 10, 
2024.
    (3) For GE material identified in this AD, contact GE 1 Neumann 
Way, Cincinnati, OH 45215; phone: (513) 552-3272; email: 
ge.com">aviation.fleetsupport@ge.com; website: ge.com.
    (4) You may view this material at FAA, Airworthiness Products 
Section, Operational Safety Branch, 1200 District Avenue, 
Burlington, MA 01803. For information on the availability of this 
material at the FAA, call (817) 222-5110.

[[Page 1365]]

    (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/[email protected]">www.archives.gov/federal-register/cfr/[email protected].

    Issued on December 6, 2024.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2025-00208 Filed 1-7-25; 8:45 am]
BILLING CODE 4910-13-P
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