AD 2020-18-14

This AD is effective October 21, 2020.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of October 21, 2020.

For service information identified in this final rule, contact General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; phone: 513-552-3272; email: aviation.fleetsupport@ae.ge.com. You may view this service information 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 781-238-7759. It is also available on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-0494.

Stephen Elwin, Aerospace Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 781-238-7236; fax: 781-238-7199; email: stephen.l.elwin@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 all GE GE90-110B1 and GE90-115B model turbofan engines with a certain HPT rotor stage 2 disk installed. The NPRM published in the Federal Register on May 18, 2020 (85 FR 29676). The NPRM was prompted by a report from the manufacturer that a subsurface anomaly was found on a HPT rotor stage 2 disk. The NPRM proposed to require a USI of the HPT rotor stage 2 disk and, depending on the result of the inspection, replacement of the HPT rotor stage 2 disk with a part eligible for installation. The FAA is issuing this AD to address the unsafe condition on these products.

The FAA gave the public the opportunity to participate in developing this final rule. The FAA has considered the comments received. The Boeing Company, FedEx Express, United Airlines, and the Air Line Pilots Association, International, supported the NPRM.

The FAA reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this final rule as proposed except for minor editorial changes. The FAA has determined that these minor changes:

• Are consistent with the intent that was proposed in the NPRM for addressing the unsafe condition; and

• Do not add any additional burden upon the public than was already proposed in the NPRM.

The FAA reviewed GE GE90-100 Service Bulletin (SB) 72-0838, dated January 31, 2020. The SB describes procedures for performing an USI of the HPT rotor stage 2 disk. This service information 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 28 engines installed on airplanes of U.S. registry. Based on updated information from the manufacturer, the FAA revised the number of engines installed on airplanes of U.S. registry from 12 in the NPRM to 28 in this final rule.

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 inspection. The FAA has no way of determining the number of engines that might need this replacement:

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) Would not affect intrastate aviation in Alaska, and

(3) Would 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 (AD):