[Federal Register Volume 87, Number 237 (Monday, December 12, 2022)]
[Rules and Regulations]
[Pages 75918-75920]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-26831]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0989; Project Identifier AD-2022-00468-E; 
Amendment 39-22236; AD 2022-23-09]
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) GE90-90B, GE90-94B, GE90-110B1, 
and GE90-115B model turbofan engines. This AD was prompted by a 
manufacturer investigation that revealed that certain high-pressure 
turbine (HPT) stage 1 disks, HPT stage 2 disks, and stages 7-9 
compressor rotor spools were manufactured from powder metal material 
suspected to contain iron inclusion. This AD requires the replacement 
of the affected HPT stage 1 disks, HPT stage 2 disks, and stages 7-9 
compressor rotor spools. The FAA is issuing this AD to address the 
unsafe condition on these products.

DATES: This AD is effective January 17, 2023.

[[Page 75919]]


ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov by 
searching for and locating Docket No. FAA-2022-0989; 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 GE GE90-90B, 
GE90-94B, GE90-110B1, and GE90-115B model turbofan engines. The NPRM 
published in the Federal Register on September 09, 2022 (87 FR 55319). 
The NPRM was prompted by a manufacturer investigation that revealed 
that certain HPT stage 1 disks, HPT stage 2 disks, and stages 7-9 
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 HPT stage 1 disks, HPT stage 
2 disks, and stages 7-9 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 the replacement of certain HPT stage 
1 disks, HPT stage 2 disks, and stages 7-9 compressor rotor spools. 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 Air Line Pilots Association, International, FedEx Express, and The 
Boeing Company. All commenters supported the NPRM without change.

Conclusion

    The FAA reviewed the relevant data, considered the comments 
received, and determined that air safety requires adopting the AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. This AD is adopted as proposed in the 
NPRM.

Related Service Information

    The FAA reviewed the following service information issued by GE, 
which specifies procedures for removing the affected HPT stage 2 disk 
from service. These documents are distinct since they apply to 
different engine models.
     GE90-100 Service Bulletin 72-0893 R01, dated November 30, 
2021.
     GE90-100 Service Bulletin 72-0899 R00, dated April 29, 
2022.
    The FAA also reviewed GE90-100 Service Bulletin 72-0897 R00, dated 
February 23, 2022. This service information specifies procedures for 
removing the affected stages 7-9 compressor rotor spool from service. 
The FAA also reviewed GE90 Service Bulletin 72-1214 R00, dated April 
29, 2022. This service information specifies procedures for removing 
the affected HPT stage 1 disk and HPT stage 2 disk from service.

Costs of Compliance

    The FAA estimates that this AD affects 1 engine installed on 
airplanes of U.S. registry. The FAA estimates that 0 engines installed 
on airplanes of U.S. registry require replacement of the HPT stage 1 
disk or stages 7-9 compressor rotor spool.
    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 HPT stage 2 disk.........  8 work-hours x $85 per    $459,473                   $460,153        $460,153
                                    hour = $680.              (pro[dash]rated).
Replace HPT stage 1 disk.........  8 work-hours x $85 per    $867,041                    867,721               0
                                    hour = $680.              (pro[dash]rated).
Replace stages 7[dash]9            8 work-hours x $85 per    $442,204                    442,884               0
 compressor rotor spool.            hour = $680.              (pro[dash]rated).
----------------------------------------------------------------------------------------------------------------

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,

[[Page 75920]]

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:

2022-23-09 General Electric Company: Amendment 39-22236; Docket No. 
FAA-2022-0989; Project Identifier AD-2022-00468-E.

(a) Effective Date

    This airworthiness directive (AD) is effective January 17, 2023.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company GE90-90B, GE90-94B, 
GE90-110B1, and GE90-115B model turbofan engines with an installed 
high-pressure turbine (HPT) stage 1 disk, HPT stage 2 disk, or 
stages 7-9 compressor rotor spool with a part number (P/N) and 
serial number (S/N) identified in Table 1 to paragraph (c) of this 
AD.

Table 1 to Paragraph (c)--Affected HPT Stage 1 Disks, HPT Stage 2 Disks,
                 and Stages 7-9 Compressor Rotor Spools
------------------------------------------------------------------------
                Part name                       P/N             S/N
------------------------------------------------------------------------
HPT stage 1 disk........................      1847M95G04        GWN0R5K4
HPT stage 2 disk........................      1711M47G13        TMT5N068
HPT stage 2 disk........................      1865M14P04        TMT5P744
                                                                TMT5P745
                                                                TMT5P749
                                                                TMT5P755
                                                                TMT5P762
Stages 7-9 compressor rotor spool.......      2032M23G02        GWN0R5M5
------------------------------------------------------------------------

(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 1 disks, HPT stage 2 disks, and 
stages 7-9 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 1 disks, HPT stage 2 disks, and stages 
7-9 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 400 flight cycles after the effective date 
of this AD, remove the affected HPT stage 1 disk, HPT stage 2 disk, 
and stages 7-9 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 1 disk, HPT stage 2 disk, and stages 
7-9 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 1 disk, HPT stage 2 disk, or stages 
7-9 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, ``affected engines not in 
service'' are affected 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 
1 disk, HPT stage 2 disk, or stages 7-9 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 November 1, 2022.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2022-26831 Filed 12-9-22; 8:45 am]
BILLING CODE 4910-13-P


