[Federal Register Volume 87, Number 182 (Wednesday, September 21, 2022)]
[Rules and Regulations]
[Pages 57575-57578]
[FR Doc No: 2022-19853]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0516; Project Identifier AD-2022-00262-E;
Amendment 39-22157; AD 2022-18-06]
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 all
General Electric Company (GE) GE90-110B1 and GE90-115B model turbofan
engines and certain GE90-76B, GE90-85B, GE90-90B, and GE90-94B model
turbofan engines. This AD was prompted by the detection of melt-related
freckles in the forgings and billets, which may reduce the life of
certain rotating compressor discharge pressure (CDP) high-pressure
turbine (HPT) seals (rotating CDP seals), interstage HPT rotor seals,
and HPT rotor stage 2 disks. This AD requires revising the
airworthiness limitations section (ALS) of the applicable GE90-100
Engine Manual (EM) and the operator's existing approved maintenance
program or inspection program, as applicable, to incorporate reduced
life limits for these parts. This AD also requires the removal and
replacement of certain interstage HPT rotor seals, identified by serial
number (S/N), installed on GE90-76B, GE90-85B, GE90-90B, and GE90-94B
model turbofan engines. The FAA is issuing this AD to address the
unsafe condition on these products.

DATES: This AD is effective October 26, 2022.

ADDRESSES: For service information identified in this final rule,
contact General Electric Company, 1 Neumann Way, Cincinnati, OH 45215;
phone:<PHONE_NUMBER>; email: [email protected]; website:
www.ge.com. You may view this service information 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<PHONE_NUMBER>.

Examining the AD Docket

    You may examine the AD docket at www.regulations.gov by searching
for and locating Docket No. FAA-2022-0516; 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:<PHONE_NUMBER>; 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 all GE GE90-110B1 and
GE90-115B model turbofan engines and certain GE90-76B, GE90-85B, GE90-
90B, and GE90-94B model turbofan engines. The NPRM published in the
Federal Register on May 27, 2022 (87 FR 32098). The NPRM was prompted
by notification by the engine manufacturer of the detection of melt-
related freckles in the forgings and billets, which may reduce the life
of certain rotating CDP seals, interstage HPT rotor seals, and HPT
rotor stage 2 disks on GE90-110B1 and GE90-115B model turbofan engines
and may reduce the life of certain interstage HPT rotor seals on GE90-
76B, GE90-85B, GE90-90B, and GE90-94B model turbofan engines. The
manufacturer's investigation determined that, as a result of such
freckles forming in the forgings and billets, certain rotating CDP
seals, interstage HPT rotor seals, and HPT rotor stage 2 disks (life-
limited parts (LLPs)) may have undetected subsurface anomalies that
developed during the manufacturing process, resulting in reduced
material properties and a lower fatigue life capability. Reduced
material properties may cause premature LLP fracture, which could
result in uncontained debris release. As a result of its investigation,
the manufacturer determined the need to reduce the life limits of
certain LLPs. To reflect these reduced life limits, the manufacturer
revised the ALS of the affected GE90-100 EMs. Additionally, the
manufacturer published service information that specifies procedures
for the removal and replacement of certain interstage HPT rotor seals
installed on GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan
engines. In the NPRM, the FAA proposed to require revising the ALS of
the applicable GE90-100 EM and the operator's existing approved
maintenance program or inspection program, as applicable, to
incorporate reduced life limits for certain LLPs. The NPRM also
proposed to require the removal and replacement of certain interstage
HPT rotor seals. 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 six commenters. The commenters were
Air Line Pilots Association, International (ALPA), American Airlines,
The Boeing Company (Boeing), FedEx Express, Japan Airlines, and United
Airlines. Five of the commenters, ALPA, American Airlines, Boeing,
FedEx Express, and United Airlines, supported the proposal without
change. The following presents the comment received on the NPRM and the
FAA's response.

Request To Refer to Service Information

    Japan Airlines requested that the FAA refer to GE90 SB 72-1211,
latest revision, in the AD as the appropriate source of service
information for the required actions. Japan Airlines noted that this
would confirm the source of the affected interstage HPT rotor seal for
the GE90-76B, GE90-85B, GE90-90B, and GE90-94B model engines. The FAA
infers that Japan Airlines is requesting for GE90 SB 72-1211 to be
incorporated by reference. The FAA disagrees with the request to
incorporate GE90 SB 72-1211 by reference. Paragraph (c)(2) of this AD
identifies the affected interstage HPT rotor seal installed on the
GE90-76B, GE90-85B, and GE90-94B model turbofan engines by part number
and serial number. 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, 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 GE90-100 SB 72-0851 R00, dated August 17, 2021.
This service information provides reduced life limits for certain LLPs.
The FAA also reviewed GE GE90 SB 72-1211 R00, dated March 9, 2022. This
service information describes procedures for removing and replacing
certain interstage HPT rotor seals.

Costs of Compliance

    The FAA estimates that this AD affects 248 engines installed on
airplanes of U.S. registry. The FAA estimates that zero engines
installed on airplanes of U.S. registry will require replacement of the
interstage HPT rotor seal.
    The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
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                                                                                Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
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Revise ALS of EM and the operator's     1 work-hour x $85 per                 $0             $85         $21,080
 existing approved maintenance program   hour = $85.
 or inspection program.
Replace interstage HPT rotor seal.....  1,500 work-hours x $85           286,331         413,831               0
                                         per hour = $127,500.
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Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. Subtitle VII: Aviation Programs,
describes in more detail the scope of the Agency's authority.
    The FAA is issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701: General requirements.
Under that section, Congress charges the FAA with promoting safe flight
of civil aircraft in air commerce by prescribing regulations for
practices, methods, and procedures the Administrator finds necessary
for safety in air commerce. This regulation is within the scope of that
authority because it addresses an unsafe condition that is likely to
exist or develop on products identified in this rulemaking action.

Regulatory Findings

    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:

2022-18-06 General Electric Company: Amendment 39-22157; Docket No.
FAA-2022-0516; Project Identifier AD-2022-00262-E.

(a) Effective Date

    This airworthiness directive (AD) is effective October 26, 2022.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to:
    (1) General Electric Company (GE) GE90-110B1 and GE90-115B model
turbofan engines; and
    (2) GE GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan
engines with an installed interstage high-pressure turbine (HPT)
rotor seal with part number (P/N) 2629M47P01 and serial number (S/N)
NCU5430D.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by the detection of melt-related freckles
in the forgings and billets, which may reduce the life of certain
rotating compressor discharge pressure (CDP) HPT seals (rotating CDP
seals), interstage HPT rotor seals, and HPT rotor stage 2 disks. The
FAA is issuing this AD to prevent failure of the rotating CDP seal,
interstage HPT rotor seal, and HPT rotor stage 2 disk. The unsafe
condition, if not addressed, could result in uncontained debris
release, damage to the engine, and damage to the airplane.

(f) Compliance

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

(g) Required Actions

    (1) For affected GE90-110B1 and GE90-115B model turbofan
engines, within 90 days after the effective date of this AD, revise
the airworthiness limitations section (ALS) of the existing GE90-100
Engine Manual (EM) and the operator's existing approved maintenance
program or inspection program, as applicable, by inserting the
following information:
    (i) For rotating CDP seal P/N 2479M03P01, insert the information
in Table 1 to paragraph (g)(1)(i) of this AD.

    Table 1 to Paragraph (g)(1)(i)--Rotating CDP Seal P/N 2479M03P01
------------------------------------------------------------------------
           Part name                     Part No.           Life cycles
------------------------------------------------------------------------
Seal, CDP......................  2479M03P01, For part             15,000
                                  serial numbers NOT
                                  listed in SB 72-0851,
                                  latest revision.
Seal, CDP......................  2479M03P01, For part              5,300
                                  serial numbers listed
                                  in SB 72-0851, latest
                                  revision APPENDIX A
                                  Table 11.
Seal, CDP......................  2479M03P01, For part             10,400
                                  serial numbers listed
                                  in SB 72-0851, latest
                                  revision APPENDIX A
                                  Table 12.
Seal, CDP......................  2479M03P01, For part             13,900
                                  serial numbers listed
                                  in SB 72-0851, latest
                                  revision APPENDIX A,
                                  Table 13.
------------------------------------------------------------------------

    (ii) For interstage HPT rotor seal P/N 2505M72P01, insert the
information in Table 2 to paragraph (g)(1)(ii) of this AD.

     Table 2 to Paragraph (g)(1)(ii)--Interstage HPT Rotor Seal P/N
                               2505M72P01
------------------------------------------------------------------------
           Part name                     Part No.           Life cycles
------------------------------------------------------------------------
Seal, Interstage...............  2505M72P01, For part             15,000
                                  serial numbers NOT
                                  listed in SB 72-0851,
                                  latest revision.
Seal, Interstage...............  2505M72P01, For part              5,500
                                  serial numbers listed
                                  in SB 72-0851, latest
                                  revision APPENDIX A
                                  Table 8.
Seal, Interstage...............  2505M72P01, For part             10,900
                                  serial numbers listed
                                  in SB 72-0851, latest
                                  revision APPENDIX A
                                  Table 9.
Seal, Interstage...............  2505M72P01, For part             14,300
                                  serial numbers listed
                                  in SB 72-0851, latest
                                  revision APPENDIX A
                                  Table 10.
------------------------------------------------------------------------

    (iii) For HPT rotor stage 2 disk P/N 2505M73P03, insert the
information in Table 3 to paragraph (g)(1)(iii) of this AD.

 Table 3 to Paragraph (g)(1)(iii)--HPT Rotor Stage 2 Disk P/N 2505M73P03
------------------------------------------------------------------------
           Part name                     Part No.           Life cycles
------------------------------------------------------------------------
Disk, Stage 2..................  2505M73P03, For part             15,000
                                  serial numbers NOT
                                  listed in SB 72-0851,
                                  latest revision.

Disk, Stage 2..................  2505M73P03, For part              3,500
                                  serial numbers listed
                                  in SB 72-0851, latest
                                  revision APPENDIX A
                                  Table 1.
Disk, Stage 2..................  2505M73P03, For part              5,100
                                  serial numbers listed
                                  in SB 72-0851, latest
                                  revision APPENDIX A
                                  Table 2.
Disk, Stage 2..................  2505M73P03, For part              5,800
                                  serial numbers listed
                                  in SB 72-0851, latest
                                  revision APPENDIX A
                                  Table 3.
Disk, Stage 2..................  2505M73P03, For part              7,200
                                  serial numbers listed
                                  in SB 72-0851, latest
                                  revision APPENDIX A
                                  Table 4.
Disk, Stage 2..................  2505M73P03, For part              8,000
                                  serial numbers listed
                                  in SB 72-0851, latest
                                  revision APPENDIX A
                                  Table 5.
Disk, Stage 2..................  2505M73P03, For part              8,300
                                  serial numbers listed
                                  in SB 72-0851, latest
                                  revision APPENDIX A
                                  Table 6.
Disk, Stage 2..................  2505M73P03, For part              8,800
                                  serial numbers listed
                                  in SB 72-0851, latest
                                  revision APPENDIX A
                                  Table 7.
------------------------------------------------------------------------

    (2) For affected GE90-76B, GE90-85B, GE90-90B, and GE90-94B
model turbofan engines, before the interstage HPT rotor seal, P/N
2629M47P01 and S/N NCU5430D, accumulates 7,400 cycles since new,
remove the affected interstage HPT rotor seal from service and
replace with a part eligible for installation.

(h) Definitions

    For the purpose of this AD, a ``part eligible for installation''
is any interstage HPT rotor seal that does not have P/N 2629M47P01
and S/N NCU5430D.

(i) 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 (j)(1) 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) Related Information

    (1) For more information about this AD, contact Alexei Marqueen,
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue,
Burlington, MA 01803; phone:<PHONE_NUMBER>; email:
[email protected].
    (2) For service information identified (but not incorporated by
reference) in this AD, contact General Electric Company, 1 Neumann
Way, Cincinnati, OH 45215; phone:<PHONE_NUMBER>; email:
[email protected]; website: www.ge.com. You may view this
referenced service information 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<PHONE_NUMBER>.

(k) Material Incorporated by Reference

    None.

    Issued on August 18, 2022.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2022-19853 Filed 9-20-22; 8:45 am]
BILLING CODE 4910-13-P