Document ID: FAA-2023-0663-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: General Electric Company Turbofan Engines
Posted Date: 2023-04-13T04:00Z

[Federal Register Volume 88, Number 71 (Thursday, April 13, 2023)]
[Proposed Rules]
[Pages 22383-22385]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-07648]

 ========================================================================
 Proposed Rules
                                                 Federal Register
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 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 88, No. 71 / Thursday, April 13, 2023 / 
Proposed Rules  

[[Page 22383]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-0663; Project Identifier AD-2023-00020-E]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain General Electric Company (GE) GEnx-1B and GEnx-2B model 
turbofan engines. This proposed AD was prompted by a manufacturer 
investigation that revealed that certain stages 6-10 compressor rotor 
spools and forward seals were manufactured from powder metal material 
suspected to contain iron inclusion. This proposed AD would require the 
replacement of the affected stages 6-10 compressor rotor spools and 
forward seals. 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 May 30, 
2023.

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 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.
    AD Docket: You may examine the AD docket at regulations.gov by 
searching for and locating Docket No. FAA-2023-0663; 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.
    Material Incorporated by Reference:
     For GE service information identified in this NPRM, 
contact General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; 
phone: (513) 552-3272; email: ge.com">[email protected]ge.com; website: 
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.

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-2023-0663; Project Identifier 
AD-2023-00020-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 
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 a high-pressure turbine stage 2 disk manufactured from the 
same powder metal material used to manufacture certain stages 6-10 
compressor rotor spools and forward seals for GEnx-1B64/P2, GEnx-1B67/
P2, GEnx-1B70/75/P2, GEnx-1B70/P2, GEnx-1B70C/P2, GEnx-1B74/75/P2, 
GEnx-1B76/P2, GEnx-1B76A/P2, and GEnx-2B67/P model turbofan engines. A 
manufacturer investigation determined that the iron inclusion was 
introduced during the manufacturing process from raw material filtering 
screens that had degraded, and certain stages 6-10 compressor rotor 
spools and forward seals manufactured using the same process may have 
reduced material properties and a lower fatigue life capability due to 
the iron inclusion. Further investigation by the manufacturer 
identified additional degraded filtering screens which had the 
potential to increase the population of parts that were subjected to 
iron inclusion during manufacturing. As a result of its investigation, 
GE published service information that specifies procedures for the 
removal and replacement of certain stages 6-10 compressor rotor spools 
and forward seals. This condition, if not addressed, could result in 
uncontained debris

[[Page 22384]]

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 Under 1 CFR Part 51

    The FAA reviewed GE GEnx-1B Service Bulletin 72-0515 R00, Initial 
Issue, dated January 31, 2023. The FAA also reviewed GE GEnx-2B Service 
Bulletin 72-0452 R00, Initial Issue, dated January 31, 2023. This 
service information specifies procedures for removal and replacement of 
the stages 6-10 compressor rotor spool and forward seal. 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.

Proposed AD Requirements in This NPRM

    This proposed AD would require removal of the affected stages 6-10 
compressor rotor spools and forward seals and replacement with a part 
eligible for installation.

Interim Action

    The FAA considers that this proposed AD would be an interim action. 
If final action is later identified, the FAA might consider additional 
rulemaking.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 13 engines installed on airplanes of U.S. registry. The FAA 
estimates that nine of the 13 engines will require replacing the stages 
6-10 compressor rotor spool and four of the 13 engines will require 
replacing the forward seal.
    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 stages 6-10 compressor rotor    8 work-hours x $85 per          $841,088        $841,768      $7,575,912
 spool.                                  hour = $680.
Replace forward seal..................  8 work-hours x $85 per           389,976         390,656       1,562,624
                                         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

    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-2023-0663; Project 
Identifier AD-2023-00020-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by May 30, 2023.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company (GE) GEnx-1B64/P2, 
GEnx-1B67/P2, GEnx-1B70/75/P2, GEnx-1B70/P2, GEnx-1B70C/P2, GEnx-
1B74/75/P2, GEnx-1B76/P2, GEnx-1B76A/P2, and GEnx-2B67/P model 
turbofan engines with an installed:
    (1) Stages 6-10 compressor rotor 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 72-0515, Initial Issue, dated 
January 31, 2023 (GEnx-1B 72-0515); or
    (2) Forward seal having a P/N and S/N listed in paragraph 4, 
Appendix--A, Table 2 of GEnx-1B 72-0515; or
    (3) Stages 6-10 compressor rotor spool having a P/N and S/N 
listed in paragraph 4, Appendix--A, Table 1 of GE GEnx-2B Service 
Bulletin 72-0452, Initial Issue, dated January 31, 2023. (GEnx-2B 
72-0452); or
    (4) Forward seal having a P/N and S/N listed in paragraph 4, 
Appendix--A, Table 2 of GEnx-2B 72-0452.

(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 certain stages 6-10 compressor rotor spools and forward 
seals were subject to iron inclusion introduced during the 
manufacturing process. The FAA is issuing this AD to prevent 
fracture and potential uncontained failure of certain stages 6-10 
compressor rotor spools and forward seals. The unsafe condition, if 
not addressed, could result in uncontained debris release, damage to 
the engine, and damage to the aircraft.

[[Page 22385]]

(f) Compliance

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

(g) Required Actions

    (1) For affected GEnx-1B model turbofan engines, at the next 
piece-part exposure after the effective date of this AD, or before 
the affected stages 6-10 compressor rotor spool reaches the cyclic 
removal threshold listed in paragraph 4., Appendix--A, Table 1 of 
GEnx-1B 72-0515, whichever occurs first, remove the affected stages 
6-10 compressor rotor spool from service and replace with a part 
eligible for installation.
    (2) For affected GEnx-1B model turbofan engines, at the next 
piece-part exposure after the effective date of this AD, or before 
the affected forward seal exceeds the cyclic removal threshold 
listed in paragraph 4., Appendix--A, Table 2 of GEnx-1B 72-0515, 
whichever occurs first, remove the affected forward seal from 
service and replace with a part eligible for installation.
    (3) For affected GEnx-2B model turbofan engines, at the next 
piece-part exposure after the effective date of this AD, or before 
the affected stages 6-10 compressor rotor spool exceeds the cyclic 
removal threshold listed in paragraph 4., Appendix--A, Table 1 of 
GEnx-2B 72-0452, whichever occurs first, remove the affected stages 
6-10 compressor rotor spool from service and replace with a part 
eligible for installation.
    (4) For affected GEnx-2B model turbofan engines, at the next 
piece-part exposure after the effective date of this AD, or before 
the affected forward seal exceeds the cyclic removal threshold 
listed in paragraph 4., Appendix--A, Table 2 of GEnx-2B 72-0452, 
whichever occurs first, remove the affected forward seal from 
service and replace with a part eligible for installation.

(h) Definitions

    (1) For the purpose of this AD, a ``part eligible for 
installation'' is any stages 6-10 compressor rotor spool or forward 
seal with a P/N and S/N not listed in paragraph 4, Appendix--A, 
Table 1 or paragraph 4, Appendix--A, Table 2 of GEnx-1B 72-0515 or 
GEnx-2B 72-0452.
    (2) For the purpose of this AD, ``piece-part exposure'' is when 
the affected part is removed from the engine.

(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) 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

    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].

(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) GE GEnx-1B Service Bulletin 72-0515, Initial Issue, dated 
January 31, 2023.
    (ii) GE GEnx-2B Service Bulletin 72-0452, Initial Issue, dated 
January 31, 2023.
    (3) For GE service information identified in this AD, contact 
General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; 
phone: (513) 552-3272; email: ge.com">[email protected]ge.com; website: 
ge.com.
    (4) You may view this service information 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.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on April 1, 2023.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-07648 Filed 4-12-23; 8:45 am]
BILLING CODE 4910-13-P