
[Federal Register Volume 88, Number 248 (Thursday, December 28, 2023)]
[Proposed Rules]
[Pages 89632-89633]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-28703]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-2237; Project Identifier AD-2023-01057-E]
RIN 2120-AA64


Airworthiness Directives; International Aero Engines, LLC Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Proposed rule; withdrawal.

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SUMMARY: The FAA is withdrawing a notice of proposed rulemaking (NPRM) 
that proposed to supersede Airworthiness Directive (AD) 2022-19-15, 
which applies to certain International Aero Engines, LLC (IAE LLC) 
Model PW1100G series engines; and AD 2023-16-07, which applies to 
certain IAE LLC Model PW1100G series engines and PW1400G series 
engines. AD 2022-19-15 requires an angled ultrasonic inspection (AUSI) 
of the high-pressure turbine (HPT) 1st-stage disk and HPT 2nd-stage 
disk, and replacement if necessary. AD 2023-16-07 requires an AUSI of 
the HPT 1st-stage hub (also known as the HPT 1st-stage disk) and HPT 
2nd-stage hub (also known as the HPT 2nd-stage disk) for cracks, and 
replacement if necessary, which is terminating action for AD 2022-19-
15. The NPRM was prompted by a manufacturer investigation that 
determined an increased risk of powder metal anomalies for all powder 
metal parts in certain powder metal production campaigns, which are 
susceptible to failure significantly earlier than previously 
determined. The NPRM would have retained the AUSI requirement for 
certain HPT 1st-stage and HPT 2nd-stage hubs from AD 2023-16-07. The 
NPRM would also have required performing an AUSI of the HPT 1st-stage 
hub, HPT 2nd-stage hub, high-pressure compressor (HPC) 7th-stage 
integrally bladed rotor (IBR-7), and HPC 8th-stage integrally bladed 
rotor (IBR-8) for cracks and replacement if necessary. The NPRM would 
also have required accelerated replacement of the HPC IBR-7, HPC IBR-8, 
HPC rear hub, HPT 1st-stage hub, HPT 1st-stage air seal, HPT 1st-stage 
blade retaining plate, HPT 2nd-stage hub, HPT 2nd-stage blade retaining 
plate, and HPT 2nd-stage rear seal. Since issuance of the NPRM, the FAA 
has received information that an error was inadvertently included in 
the compliance times for some of the HPT 1st-stage and 2nd-stage hubs, 
which would have required removal significantly later than necessary. 
Accordingly, the NPRM is withdrawn.

DATES: As of December 28, 2023, the proposed rule, which was published 
in the Federal Register on December 12, 2023 (88 FR 86088), is 
withdrawn.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov by 
searching for and locating Docket No. FAA-2023-2237; 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 AD action, the 
NPRM, any comments received, and other information. The street address 
for Docket Operations is Docket Operations, M-30, West Building Ground 
Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Carol Nguyen, Aviation Safety 
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: 
(781) 238-7655; email: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued an NPRM that proposed to amend 14 CFR part 39 by 
adding an AD that would apply to certain IAE LLC Model PW1122G-JM, 
PW1124G1-JM, PW1124G-JM, PW1127G-JM, PW1127G1-JM, PW1127GA-JM, PW1129G-
JM, PW1130G-JM, PW1133G-JM, PW1133GA-JM, PW1428G-JM, PW1428GA-JM, 
PW1428GH-JM, PW1431G-JM, PW1431GA-JM, and PW1431GH-JM engines. The NPRM 
was published in the Federal Register on December 12, 2023 (88 FR 
86088). The NPRM was prompted by an analysis of an event involving an 
IAE LLC Model PW1127GA-JM engine, which experienced failure of a HPC 
IBR-7 that resulted in an engine shutdown and aborted takeoff; and the 
FAA's determination to supersede AD 2022-19-15, Amendment 39-22184 (87 
FR 59660, October 3, 2022; corrected October 24, 2022 (87 FR 64156)) 
(AD 2022-19-15), and AD 2023-16-07, Amendment 39-22526 (88 FR 56999, 
August 22, 2023) (AD 2023-16-07). The NPRM proposed to retain the AUSI 
requirement for certain HPT 1st-stage and HPT 2nd-stage hubs from AD 
2023-16-07. The NPRM also proposed to require performing an AUSI of the 
HPT

[[Page 89633]]

1st-stage hub, HPT 2nd-stage hub, HPC IBR-7, and HPC IBR-8 for cracks 
and replacement if necessary. The NPRM also proposed to require 
accelerated replacement of the HPC IBR-7, HPC IBR-8, HPC rear hub, HPT 
1st-stage hub, HPT 1st-stage air seal, HPT 1st-stage blade retaining 
plate, HPT 2nd-stage hub, HPT 2nd-stage blade retaining plate, and HPT 
2nd-stage rear seal.
    The proposed actions were intended to address failure of the HPT 
1st-stage hub, HPT 2nd-stage hub, HPC IBR-7, and HPC IBR-8, which could 
result in uncontained hub failure, release of high-energy debris, 
damage to the engine, damage to the airplane, and loss of the airplane.

Actions Since the NPRM Was Issued

    Since issuance of the NPRM, the FAA has received information from 
Pratt & Whitney that an error was inadvertently included in the removal 
times for some of the HPT 1st-stage and 2nd-stage hubs, which would 
have required removal significantly later than necessary. Because the 
removal timeframe needed to be shortened, the FAA determined it is 
necessary to withdraw the NPRM and issue a new NPRM for the unsafe 
condition with the correct compliance times.
    Withdrawal of the NPRM constitutes only such action and does not 
preclude the FAA from further rulemaking on this issue, nor does it 
commit the FAA to any course of action in the future.

Comments

    The FAA received comments on the NPRM. However, due to the FAA's 
determination that it is necessary to withdraw and issue a new NPRM, 
the comments will be copied to Docket No. FAA-2023-2401 and addressed 
in the final rule for that AD action. Additionally, the FAA requests 
that the commenters review the new NPRM at Docket No. FAA-2023-2401.

FAA's Conclusions

    Upon further consideration, the FAA has determined that the NPRM 
does not adequately address the identified unsafe condition. 
Accordingly, the NPRM is withdrawn.

Regulatory Findings

    Since this action only withdraws an NPRM, it is neither a proposed 
nor a final rule. This action therefore is not covered under Executive 
Order 12866, the Regulatory Flexibility Act, or DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979).

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Withdrawal

0
Accordingly, the notice of proposed rulemaking (Docket No. FAA-2023-
2237), which was published in the Federal Register on December 12, 2023 
(88 FR 86088), is withdrawn.

    Issued on December 21, 2023.
Caitlin Locke,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2023-28703 Filed 12-22-23; 4:15 pm]
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