[Federal Register Volume 89, Number 83 (Monday, April 29, 2024)]
[Rules and Regulations]
[Pages 33215-33218]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-09109]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-0771; Project Identifier AD-2023-01251-E; 
Amendment 39-22720; AD 2024-06-15]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain General Electric Company (GE) Model GE90-110B1 and GE90-115B 
engines. This AD was prompted by a report of an aborted takeoff due to 
left engine failure caused by liberation of the interstage high-
pressure turbine (HPT) rotor seal rim. This AD requires repetitive 
ultrasonic inspections (USIs) of the interstage HPT rotor seal for 
cracks and removal from service if necessary. As a mandatory 
terminating action to the repetitive USIs of the interstage HPT rotor 
seal, this AD also requires replacement of the interstage HPT rotor 
seal. The FAA is issuing this AD to address the unsafe condition on 
these products.

DATES: This AD is effective May 14, 2024.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of May 14, 
2024.
    The FAA must receive comments on this AD by June 13, 2024.

ADDRESSES: You may send comments, using the procedures found in 14 CFR

[[Page 33216]]

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 under 
Docket No. FAA-2024-0771; 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 street address for Docket Operations is listed above.
    Material Incorporated by Reference:
     For service information identified in this final rule, 
contact General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; 
phone: (513) 552-3272; email: ge.com">aviation.fleetsupport@ae.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. It is 
also available at regulations.gov under Docket No. FAA-2024-0771.

FOR FURTHER INFORMATION CONTACT: Alexander Thickstun, Aviation Safety 
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: 
(202) 267-8292; email: [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written data, views, or arguments 
about this final rule. Send your comments to an address listed under 
ADDRESSES. Include ``FAA-2024-0771 Project Identifier AD-2023-01251-E'' 
at the beginning of your comments. The most helpful comments reference 
a specific portion of the final rule, 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 final rule 
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 final rule.

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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to 
Alexander Thickstun, Aviation Safety Engineer, FAA, 2200 South 216th 
Street, Des Moines, WA 98198. Any commentary that the FAA receives 
which is not specifically designated as CBI will be placed in the 
public docket for this rulemaking.

Background

    On October 19, 2019, a The Boeing Company Model 777 airplane, 
powered by GE Model GE90-115B engines, experienced an engine failure, 
which resulted in an aborted takeoff. A manufacturer investigation 
determined that the engine failure was caused by rim liberation of the 
interstage HPT rotor seal. Additional root cause analysis determined 
that rim liberation was the result of high cycle fatigue cracks 
initiating at the interstage seal web holes occurring from atypical 
intermittent operating conditions with short durations. As a result, 
the FAA issued Emergency AD 2019-21-51, Amendment 39-19798 (84 FR 
64195, November 21, 2019) for certain GE GE90-115B model turbofan 
engines; Emergency AD 2020-01-55, Amendment 39-19838 (85 FR 8386, 
February 14, 2020) for certain GE GE90-115B model turbofan engines; and 
AD 2020-10-04, Amendment 39-21122 (85 FR 27909, May 12, 2020) for all 
GE GE90-110B1 and GE90-115B model turbofan engines with a certain 
interstage HPT rotor seal installed to remove affected parts from 
engines that had accumulated high flight cycles (FCs). Since the FAA 
issued those three ADs, the affected engines have continued to 
accumulate FCs, and the manufacturer has identified additional parts 
for inspection and removal. This condition, if not addressed, could 
result in uncontained HPT failure, release of high-energy debris, 
damage to the engine, damage to the airplane, and possible loss of the 
airplane. The FAA is issuing this AD to address the unsafe condition on 
these products.

FAA's Determination

    The FAA is issuing this AD because the agency has determined the 
unsafe condition described previously is likely to exist or develop in 
other products of the same type design.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed GE GE90-100 Service Bulletin (SB) 72-0908 R00, 
dated July 7, 2023. The SB specifies procedures for performing a USI of 
the interstage HPT rotor seal. 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.

AD Requirements

    This AD requires repetitive USIs of the interstage HPT rotor seal 
for cracks and removal from service if necessary. As a mandatory 
terminating action to the repetitive USIs of the interstage HPT rotor 
seal, this AD requires replacement of the interstage HPT rotor seal.

Interim Action

    The FAA considers this AD to be an interim action. The unsafe 
condition is still under investigation by the manufacturer and, 
depending on the results of that investigation, the FAA may consider 
further rulemaking action.

Justification for Immediate Adoption and Determination of the Effective 
Date

    Section 553(b)(3)(B) of the Administrative Procedure Act (APA) (5 
U.S.C. 551 et seq.) authorizes agencies to dispense with notice and 
comment procedures for rules when the agency, for ``good cause,'' finds 
that those procedures are ``impracticable, unnecessary, or contrary to 
the public interest.'' Under this section, an agency, upon finding good 
cause, may issue a final rule without providing notice and seeking 
comment prior to issuance. Further, section 553(d) of the APA 
authorizes agencies to make rules effective in less than thirty days, 
upon a finding of good cause.
    The FAA justifies waiving notice and comment prior to adoption of 
this rule because no domestic operators use this

[[Page 33217]]

product. It is unlikely that the FAA will receive any adverse comments 
or useful information about this AD from any U.S. operator. 
Accordingly, notice and opportunity for prior public comment are 
unnecessary, pursuant to 5 U.S.C. 553(b)(3)(B). In addition, for the 
foregoing reason(s), the FAA finds that good cause exists pursuant to 5 
U.S.C. 553(d) for making this amendment effective in less than 30 days.

Regulatory Flexibility Act

    The requirements of the Regulatory Flexibility Act (RFA) do not 
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt 
a rule without prior notice and comment. Because FAA has determined 
that it has good cause to adopt this rule without prior notice and 
comment, RFA analysis is not required.

Costs of Compliance

    The FAA estimates that this AD affects 0 engines installed on 
airplanes of U.S. registry.
    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
----------------------------------------------------------------------------------------------------------------
Remove interstage HPT rotor seal......  100 work-hours x $85 per        $540,000        $548,500              $0
                                         hour = $8,500.
Perform USI of interstage HPT rotor     2 work-hours x $85 per                 0             170               0
 seal.                                   hour = $170.
----------------------------------------------------------------------------------------------------------------

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, and
    (2) Will not affect intrastate aviation in Alaska.

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:

2024-06-15 General Electric Company: Amendment 39-22720; Docket No. 
FAA-2024-0771; Project Identifier AD-2023-01251-E.

(a) Effective Date

    This airworthiness directive (AD) is effective May 14, 2024.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company (GE) Model GE90-
110B1 and GE90-115B engines with an installed interstage high-
pressure turbine (HPT) rotor seal having a part number and serial 
number listed in Table 1 or Table 2 of GE GE90-100 Service Bulletin 
(SB) 72-A0908 R00, dated July 7, 2023 (GE SB 72-A0908).

(d) Subject

    Joint Aircraft System Component (JASC) Code 7250, Turbine 
Section.

(e) Unsafe Condition

    This AD was prompted by a report of an aborted takeoff due to 
left engine failure caused by liberation of the interstage HPT rotor 
seal rim. The FAA is issuing this AD to prevent failure of the HPT. 
The unsafe condition, if not addressed, could result in uncontained 
HPT failure, release of high-energy debris, damage to the engine, 
damage to the airplane, and possible loss of the airplane.

(f) Compliance

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

(g) Required Actions

    (1) Perform an ultrasonic inspection (USI) of the interstage HPT 
rotor seal in accordance with the Accomplishment Instructions, 
paragraph 3.B.(2), of GE SB 72-A0908, as follows:
    (i) Perform an initial USI before reaching the part cycles since 
new limit listed in Table 1 or Table 2, as applicable, of GE SB 72-
A0908, or within 10 flight cycles after the effective date of this 
AD, whichever occurs later; and
    (ii) Repeat the USI thereafter within every 100 cycles or 175 
cycles, as applicable, as listed in Table 1 or Table 2 of GE SB 72-
A0908, since the last inspection.
    (2) If, during any USI required by paragraph (g)(1)(i) or (ii) 
of this AD, a non-serviceable indication is found, as defined in 
paragraph 3.B.(2)(b) of GE SB 72-A0908, before further flight, 
remove the interstage HPT rotor seal from service.

(h) Mandatory Terminating Action

    As a terminating action to the repetitive USI required by 
paragraph (g)(1)(i) or (ii) of this AD, at the next engine shop 
visit after the effective date of this AD, remove the affected 
interstage HPT rotor seal from service.

(i) Definition

    For the purpose of this AD, an ``engine shop visit'' is the 
induction of an engine into the shop for maintenance involving the 
separation of pairs of major mating engine case flanges, except 
separation of engine flanges solely for the purposes of 
transportation of the engine without subsequent maintenance, which 
does not constitute an engine shop visit.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, AIR-520 Continued Operational Safety Branch, 
FAA, has the authority to approve AMOCs for this AD, if

[[Page 33218]]

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 AIR-520 Continued 
Operational Safety Branch, 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) Additional Information

    For more information about this AD, contact Alexander Thickstun, 
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, 
WA 98198; phone: (202) 267-8292; email: 
[email protected].

(l) 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) General Electric Company GE90-100 Service Bulletin 72-0908 
R00, dated July 7, 2023.
    (ii) [Reserved]
    (3) For service information identified in this AD, contact 
General Electric Company, 1 Newman Way, Cincinnati, OH 45215; phone: 
(513) 552-3272; email:ge.com">aviation.fleetsupport@ae.ge.com; website: 
ge.com.
    (4) 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.
    (5) You may view this material at the National Archives and 
Records Administration (NARA). For information on the availability 
of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected].

    Issued on March 25, 2024.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2024-09109 Filed 4-26-24; 8:45 am]
BILLING CODE 4910-13-P