AD 2025-14-03

This AD is effective August 25, 2025.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of August 25, 2025.

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2024-1885; 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 address for Docket Operations is U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

Material Incorporated by Reference:

• For GE material identified in this AD, contact GE, 1 Neumann Way, Cincinnati, OH 45215; phone: (513) 552-3272; email: aviation.fleetsupport@ge.com; website: ge.com.

• You may view this material 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-2024-1885.

Alexei Marqueen, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (781) 238-7178; email: alexei.t.marqueen@faa.gov.

The FAA issued a supplemental notice of proposed rulemaking (SNPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain GE Model CF34-10E2A1, CF34-10E6, CF34-10E6A1, CF34-10E7, CF34-10E7-B, CF34-10E5, and CF34-10E5A1 engines. The SNPRM was published in the Federal Register on April 25, 2025 (90 FR 17345). The SNPRM was prompted by a report of indications found in certain HPT front rotating air seals at the rabbet surface where the affected part interacts with the HPT rotor disk tabs. The manufacturer investigated and determined that the indications were caused by high edge contact stress at the interface between the HPT rotor disk and the rabbet surface of the HPT front rotating air seal. The SNPRM proposed to require repetitive FPIs to detect indications or linear indications (any indication that is four times longer than the width of that same indication) in the HPT front rotating air seal and, if necessary, replacement of the HPT front rotating air seal or HPT rotor disk with parts eligible for installation. Additionally, replacing the HPT front rotating air seal with an updated design part constitutes as a terminating action for the proposed AD. The FAA has also determined that changes to the applicability are necessary, primarily based on comments received on the notice of proposed rulemaking (NPRM) (89 FR 59860; July 24, 2024) from several commenters and additional review by the FAA. The FAA is issuing this AD to address the unsafe condition on these products.

The FAA received a comment from one individual commenter. The commenter supported the SNPRM without change.

The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. Except for minor editorial changes, this AD is adopted as proposed in the SNPRM. None of the changes will increase the economic burden on any operator.

The FAA reviewed GE CF34-10E Service Bulletin 72-0341 R02, dated September 24, 2021 (GE SB 72-0341 R02). This material specifies procedures for repetitive FPIs and eddy current inspections of certain HPT front rotating air seals for indications or linear indications and, if necessary, replacement of the affected HPT front rotating air seals or the HPT rotor disk with parts eligible for installation. This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

The FAA estimates that this AD, affects 228 engines installed on airplanes of U.S. registry.

The FAA estimates the following costs to comply with this AD:

The FAA estimates the following costs to do any necessary replacements that would be required based on the results of the inspections. The agency has no way of determining the number of engines that might need these replacements:

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.

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,

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

(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by adding the following new airworthiness directive: