[Federal Register Volume 87, Number 174 (Friday, September 9, 2022)]
[Proposed Rules]
[Pages 55319-55322]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-19400]


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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]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain General Electric Company (GE) GE90-90B, GE90-94B, GE90-
110B1, and GE90-115B model turbofan engines. This proposed 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 proposed AD would 
require the replacement of the affected HPT stage 1 disks, HPT stage 2 
disks, and stages 7-9 compressor rotor spools. The FAA is proposing 
this AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by October 24, 
2022.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to www.regulations.gov. 
Follow the instructions for submitting comments.
     Fax: (202) 493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, contact General 
Electric Company, 1 Neumann Way, Cincinnati, OH 45215; phone: (513) 
552-3272;

[[Page 55320]]

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 
(817) 222-5110.

Examining the AD Docket

    You may examine the AD docket at www.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 NPRM, any comments 
received, and other information. The street address for Docket 
Operations is listed above.

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:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2022-0989; Project Identifier 
AD-2022-00468-E'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. The FAA 
will consider all comments received by the closing date and may amend 
this proposal because of those comments.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, the FAA will post all comments received, without change, to 
www.regulations.gov, including any personal information you provide. 
The agency will also post a report summarizing each substantive verbal 
contact received about this NPRM.

Confidential Business Information

    CBI is commercial or financial information that is both customarily 
and actually treated as private by its owner. Under the Freedom of 
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public 
disclosure. If your comments responsive to this NPRM contain commercial 
or financial information that is customarily treated as private, that 
you actually treat as private, and that is relevant or responsive to 
this NPRM, it is important that you clearly designate the submitted 
comments as CBI. Please mark each page of your submission containing 
CBI as ``PROPIN.'' The FAA will treat such marked submissions as 
confidential under the FOIA, and they will not be placed in the public 
docket of this NPRM. Submissions containing CBI should be sent to 
Alexei Marqueen, Aviation Safety Engineer, ECO Branch, FAA, 1200 
District Avenue, Burlington, MA 01803. Any commentary that the FAA 
receives which is not specifically designated as CBI will be placed in 
the public docket for this rulemaking.

Background

    The FAA was notified by the manufacturer of the detection of iron 
inclusion in an HPT stage 2 disk manufactured from the same powder 
metal material used to manufacture certain HPT stage 1 disks, HPT stage 
2 disks, and stages 7-9 compressor rotor spools for the GE90-90B, GE90-
94B, GE90-110B1, and GE90-115B model turbofan engines. 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. As a result of its investigation, the manufacturer published 
service information that specifies procedures for the removal and 
replacement of certain HPT stage 1 disks, HPT stage 2 disks, and stages 
7-9 compressor rotor spools installed on GE90-90B, GE90-94B, GE90-
110B1, and GE90-115B model turbofan engines. This condition, if not 
addressed, could result in uncontained debris release, damage to the 
engine, and damage to the aircraft.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of the same type design.

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.

Proposed AD Requirements in This NPRM

    This proposed AD would require the replacement of certain HPT stage 
1 disks, HPT stage 2 disks, and stages 7-9 compressor rotor spools.

Differences Between This Proposed AD and the Service Information

    GE GE90-100 Service Bulletin 72-0893 R01, dated November 30, 2021, 
and GE90-100 Service Bulletin 72-0899 R00, dated April 29, 2022, use 
the term ``HPT rotor stage 2 disk,'' while this proposed AD uses the 
term ``HPT stage 2 disk.''

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 1 engine installed on airplanes of U.S. registry. The FAA 
estimates that 0 engines installed on airplanes of U.S. registry would 
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 proposed 
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     $459,473 (average pro-       $460,153        $460,153
                                     per hour = $680.       rated cost of part).

[[Page 55321]]

 
Replace HPT stage 1 disk..........  8 work-hours x $85     $867,041 (average pro-        867,721               0
                                     per hour = $680.       rated cost of part).
Replace stages 7-9 compressor       8 work-hours x $85     $442,204 (average pro-        442,884               0
 rotor spool.                        per hour = $680.       rated cost of part).
----------------------------------------------------------------------------------------------------------------

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

    The FAA determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 this proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Would not affect intrastate aviation in Alaska, and
    (3) Would 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 Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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:

General Electric Company: Docket No. FAA-2022-0989; Project 
Identifier AD-2022-00468-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by October 24, 2022.

(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.
[GRAPHIC] [TIFF OMITTED] TP09SE22.047


[[Page 55322]]



(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].

    Issued on July 29, 2022.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2022-19400 Filed 9-8-22; 8:45 am]
BILLING CODE 4910-13-P


