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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

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

Proposed rule; withdrawal.

# 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 Accordingly, the NPRM is withdrawn.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:                         *carol.nguyen@faa.gov.*

# 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                           ( print 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

                    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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