Airworthiness Directives; General Electric Company Turbofan Engines

[Federal Register Volume 87, Number 245 (Thursday, December 22, 2022)]
[Rules and Regulations]
[Pages 78513-78515]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-27835]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0978; Project Identifier AD-2022-00460-E; 
Amendment 39-22276; AD 2022-25-20]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Turbofan 
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) GEnx-1B and GEnx-2B model 
turbofan engines. This AD was prompted by a manufacturer investigation 
that revealed that certain high-pressure turbine (HPT) stage 2 disks, 
forward seals, and stages 6-10 compressor rotor spools were 
manufactured from powder metal material suspected to contain iron 
inclusion. This AD requires replacement of the affected HPT stage 2 
disks, forward seals, and stages 6-10 compressor rotor spools. The FAA 
is issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective January 26, 2023.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov by 
searching for and locating Docket No. FAA-2022-0978; 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: Alexei Marqueen, Aviation Safety 
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 
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 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-1B), GEnx-2B67, GEnx-2B67B, and GEnx-
2B67/P (GEnx-2B) model turbofan engines. The NPRM published in the 
Federal Register on September 9, 2022 (87 FR 55328). The NPRM was 
prompted by a manufacturer investigation that revealed that certain HPT 
stage 2 disks, forward seals, and stages 6-10 compressor rotor spools 
were manufactured from powder metal material suspected to contain iron 
inclusion. Further investigation by the manufacturer determined that 
the iron inclusion is attributed to deficiencies in the manufacturing 
process. The investigation by the manufacturer also determined that 
certain GEnx-1B and GEnx-2B HPT stage 2 disks, forward seals, and 
stages 6-10 compressor rotor spools made from billets manufactured 
using the same process may have reduced material properties and a lower 
fatigue life capability due to iron inclusion, which may cause 
premature fracture and uncontained failure. In the NPRM, the FAA 
proposed to require replacement of certain HPT stage 2 disks, forward 
seals, and stages 6-10 compressor rotor spools 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 four commenters. The commenters were 
Air Line Pilots Association, International (ALPA), American Airlines, 
GE Aviation, and The Boeing Company (Boeing). ALPA, American Airlines, 
and Boeing supported the proposed AD without change. GE Aviation 
requested a change to the proposed AD. The following presents the 
comments received on the NPRM and the FAA's response to each comment.

[[Page 78514]]

Request To Add Alternate Part Numbers to AD Applicability

    GE Aviation requested that the FAA add alternate part numbers (P/
Ns) to Table 1 to paragraph (c) of this AD. GE Aviation explained that 
the forward seal and stages 6-10 compressor rotor spool may have 
reworked P/Ns that occur after entry into service. While the P/Ns 
provided in the NPRM are the best information available as to current 
P/Ns, GE requested that the FAA add certain alternate P/Ns to Table 1 
to paragraph (c), Applicability, of this final rule to ensure 
compliance.
    The FAA agrees for the reasons provided and has revised Table 1 to 
paragraph (c), Applicability, of this AD as requested by GE Aviation.

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.

Related Service Information

    The FAA reviewed GE GEnx-1B Service Bulletin 72-0505, Revision 02, 
dated April 5, 2022. The FAA also reviewed GE GEnx-2B Service Bulletin 
72-0444, Revision 02, dated April 5, 2022. This service information 
describes procedures for removing the HPT stage 2 disk, forward seal, 
and stages 6-10 compressor rotor spool. These documents are distinct 
since they apply to different engine models.

Costs of Compliance

    The FAA estimates that this AD affects 3 engines installed on 
airplanes of U.S. registry. The FAA estimates that 0 engines installed 
on airplanes of U.S. registry require replacement of the forward seal 
or HPT stage 2 disk.
    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
----------------------------------------------------------------------------------------------------------------
Replace stages 6-10 compressor     8 work-hours x $85 per    $846,519 (pro-             $847,199      $2,541,597
 rotor spool.                       hour = $680.              rated).
Replace forward seal.............  8 work-hours x $85 per    364,558 (pro-rated)         365,238               0
                                    hour = $680.
Replace HPT stage 2 disk.........  8 work-hours x $85 per    363,424 (pro-rated)         364,104               0
                                    hour = $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 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:

2022-25-20 General Electric Company: Amendment 39-22276; Docket No. 
FAA-2022-0978; Project Identifier AD-2022-00460-E.

(a) Effective Date

    This airworthiness directive (AD) is effective January 26, 2023.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company 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 
model turbofan engines with an installed high-pressure turbine (HPT) 
stage 2 disk, forward seal, or stages 6-10 compressor rotor spool 
with a part number (P/N) and serial number (S/N) identified in Table 
1 to paragraph (c) of this AD.

[[Page 78515]]



Table 1 to Paragraph (c)--Affected HPT Stage 2 Disks, Forward Seals, and
                   Stages 6-10 Compressor Rotor Spools
------------------------------------------------------------------------
            Part name                       P/N                 S/N
------------------------------------------------------------------------
HPT stage 2 disk................  2300M84P02                    TMT4AF08
                                                                TMT4AF10
                                                                TMT4AF11
                                                                TMT4AF12
Forward seal....................  2417M60P02                    VOLF1931
                                  or                            VOLF1933
                                  2759M04P01                    VOLF1942
                                  ......................        VOLF1977
                                  ......................        VOLF1993
                                  ......................        VOLF2014
Stages 6-10 compressor rotor      2357M30G02                    GWN0R86N
 spool.                           or
                                  2340M36G01
Stages 6-10 compressor rotor      2439M35G01                    GWN0RCKT
 spool.                           or                            GWN0R62G
                                  2610M90G01                    GWN0R86J
                                  ......................        GWN0R5EK
                                  ......................        GWN0R6EH
                                  ......................        GWN0R7K1
                                  ......................        GWN0R89A
Stages 6-10 compressor rotor      2439M35G02                    GWN0RA89
 spool.                                                         GWN0R6K9
                                  ......................        GWN0R7G9
                                  ......................        GWN0R7K4
                                  ......................        GWN0R752
                                  ......................        GWN0R98P
------------------------------------------------------------------------

(d) Subject

    Joint Aircraft System Component (JASC) Code 7230, Turbine Engine 
Compressor Section; 7250, Turbine Section.

(e) Unsafe Condition

    This AD was prompted by a manufacturer investigation that 
revealed that certain HPT stage 2 disks, forward seals, and stages 
6-10 compressor rotor spools were manufactured from powder metal 
material suspected to contain iron inclusion. The FAA is issuing 
this AD to prevent fracture and potential uncontained failure of 
certain HPT stage 2 disks, forward seals, and stages 6-10 compressor 
rotor 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

    (1) Before exceeding 600 flight cycles after the effective date 
of this AD, remove the affected HPT stage 2 disk, forward seal, and 
stages 6-10 compressor rotor spool from service and replace with a 
part eligible for installation.
    (2) For affected engines not in service, before further flight, 
remove the affected HPT stage 2 disk, forward seal, and stages 6-10 
compressor rotor spool and replace with a part eligible for 
installation.

(h) Definitions

    (1) For the purpose of this AD, a ``part eligible for 
installation'' is any HPT stage 2 disk, forward seal, or stages 6-10 
compressor rotor spool with a P/N and S/N not identified in Table 1 
to paragraph (c) of this AD.
    (2) For the purpose of this AD, ``engines not in service'' are 
engines that are in long-term or short-term storage as of the 
effective date of this AD.

(i) Installation Prohibition

    After the effective date of this AD, do not install an HPT stage 
2 disk, forward seal, or stages 6-10 compressor rotor spool with a 
P/N and S/N identified in Table 1 to paragraph (c) of this AD onto 
any engine.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, ECO 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 
certification office, 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, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: (781) 238-7178; email: 
[email protected].

(l) Material Incorporated by Reference

    None.

    Issued on December 2, 2022.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2022-27835 Filed 12-21-22; 8:45 am]
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