AD 2025-25-07

This AD is effective February 6, 2026.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of February 6, 2026.

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2025-1364; 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-2025-1364.

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 notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain GE Model GE90-90B, GE90-94B, GE90-110B1, and GE90-115B engines. The NPRM was published in the Federal Register on July 29, 2025 (90 FR 35642). The NPRM was prompted by the detection of iron inclusion in a turbine disk manufactured from the same powder metal material used to manufacture certain HPT stage 1 and HPT stage 2 disks for GE Model GE90-90B, GE90-94B, GE90-110B1, and GE90-115B engines. Further investigation by the manufacturer revealed that the iron inclusion is attributed to deficiencies in the manufacturing process and may cause reduced material properties and a lower fatigue life capability, which may result in premature fracture and uncontained failure. The manufacturer also informed the FAA that additional risk assessments revealed that there were no incidents of premature fracture and uncontained failure associated with the discovery of this iron inclusion material on these engines but concluded that replacement of the affected HPT stage 1 and HPT stage 2 disks is necessary to prevent any future failure events. In the NPRM, the FAA proposed to require replacement of affected HPT stage 1 and HPT stage 2 disks with parts eligible for installation. The FAA is issuing this AD to address the unsafe condition on these products.

The FAA received comments from four commenters. The commenters were the Air Line Pilots Association, International (ALPA), The Boeing Company (Boeing), FedEx Express (FedEx), and GE Aerospace. The ALPA, Boeing, and FedEx supported the NPRM without change. The following presents the comment received on the NPRM and the FAA's response to the comment.

GE Aerospace requested that the FAA revise the part number in Table 1 to Paragraph (c) of the proposed AD for serial numbers GWN0NJ92, GWN0NJ94, and GWN0NK87 from “1865M13G08” to “1865M13G07.” GE Aerospace noted that GE GE90-100 Service Bulletin 72-0926, Revision 01, dated December 22, 2023, lists the current part numbers for affected disks, and they have been confirmed with product support engineering.

The FAA agrees and has updated the part number in Table 1 to Paragraph (c) of this AD as requested.

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, and any other changes described previously, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator.

The FAA reviewed GE GE90-100 Service Bulletin 72-0926, Revision 01, dated December 22, 2023. This material specifies the affected part numbers, serial numbers, and cyclic removal thresholds for the HPT stage 1 and HPT stage 2 disks. 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 two engines installed on airplanes of U.S. registry. The FAA estimates that one engine installed on an airplane of U.S. registry will require replacement of the HPT stage 1 disk, and one engine installed on an airplane of U.S. registry will require replacement of the HPT stage 2 disk. The FAA estimates the following costs to comply with this AD:

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: