AD 2022-19-01

This AD is effective October 25, 2022.

AD Docket: You may examine the AD docket at regulations.gov by searching for and locating Docket No. FAA-2022-0587; 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.

Alexei Marqueen, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 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 GEnx-2B67/P model turbofan engines with an affected LPTR stage 4 disk or LPTR stage 6 disk installed, identified by part number and serial number. The NPRM published in the Federal Register on June 22, 2022 (87 FR 37247). The NPRM was prompted by the engine manufacturer notifying the FAA of the detection of an iron inclusion in a forging, which may reduce the fatigue life of certain LPTR stage 4 disks and LPTR stage 6 disks. The manufacturer's investigation determined that the inclusion is a melt-related defect and that, as a result of the inclusion forming in the forging, certain LPTR stage 4 disks and LPTR stage 6 disks may have reduced material properties and a lower fatigue life capability. Reduced material properties may cause premature LPTR stage 4 disk and LPTR stage 6 disk fracture, which could result in uncontained debris release. As a result of its investigation, the manufacturer published service information that specifies procedures for the removal and replacement of certain LPTR stage 4 disks and LPTR stage 6 disks installed on GEnx-2B67/P model turbofan engines. This condition, if not addressed, could result in uncontained debris release, damage to the engine, and damage to the airplane. In the NPRM, the FAA proposed to require the removal of certain LPTR stage 4 disks and LPTR stage 6 disks from service and replacement with parts eligible for installation. The FAA is issuing this AD to address the unsafe condition on these products.

The FAA received one comment, from The Boeing Company (Boeing). Boeing concurred with the contents of the NPRM.

The FAA reviewed the relevant data, considered the comment received, and determined that air safety requires adopting the 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 NPRM.

The FAA reviewed GE GEnx-2B Service Bulletin (SB) 72-0448 R00, dated February 7, 2022. This SB describes procedures for removing the affected LPTR stage 4 disks and LPTR stage 6 disks from service.

The FAA estimates that this AD affects 4 engines installed on airplanes of U.S. registry.

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: