SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all RRD Model Trent 1000-A2, ( printed page 52497) Trent 1000-AE2, Trent 1000-C2, Trent 1000-CE2, Trent 1000-D2, Trent 1000-E2, Trent 1000-G2, Trent 1000-H2, Trent 1000-J2, Trent 1000-K2, and Trent 1000-L2 engines. The NPRM was published in the Federal Register on March 16, 2026 (91 FR 12512). The NPRM was prompted by EASA AD 2025-0002, dated January 7, 2025 (EASA AD 2025-0002) (also referred to as the MCAI), issued by EASA, which is the Technical Agent for the Member States of the European Union. The MCAI states that cracking of the IP compressor VIGV on Trent 1000 Pack C engines was reported and subsequent investigation attributed the cracking to high-cycle fatigue propagation phenomenon. The MCAI also states that the engine manufacturer issued material for repetitive BSIs for cracks of the IP compressor VIGVs and depending on the inspection results, reduced inspection intervals for the repetitive BSIs or removal of the engine from service. This condition, if not addressed, could result in release of fractured parts with a steady state surge, consequent uncommanded in-flight shutdown (IFSD) and, in the case of dual-engine IFSD, reduced control of the airplane.

In the NPRM, the FAA proposed to require repetitive BSIs for cracks of the IP compressor VIGVs and, depending on the inspection results, reduced inspection intervals for the repetitive BSIs or removal of the engine from service and replacement of the IP compressor VIGVs. The FAA is issuing this AD to address the unsafe condition on these products.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-2294.

Discussion of Final Airworthiness Directive

Comments

The FAA received comments from two commenters. The commenters were the Airline Pilots Association, International (ALPA) and an individual. The following presents the comments received on the NPRM and the FAA's response to each comment.

Support for the NPRM

ALPA and an individual expressed support for the NPRM.

Request for More Frequent Inspections for All High Use Engines

An individual commenter requested that the FAA consider requiring more frequent inspections for engines that are used more often. The commenter indicated that more frequent inspections would further reduce risk.

The FAA disagrees with the commenter's request. In developing an appropriate compliance time, the FAA considered the safety implications, parts availability, and normal maintenance schedules for timely accomplishment of the required inspections. In consideration of all these factors, the FAA determined that the compliance time, as proposed, represents an appropriate interval in which the inspections can be done in a timely manner within the fleet, while still maintaining an adequate level of safety. Most ADs, including this one, permit operators to accomplish the requirements of an AD at a time earlier than the specified compliance time. However, introducing higher frequency for inspections does not necessarily result in decreasing risk. If additional data are presented that would justify a shorter compliance time, the FAA may consider further rulemaking on this issue. The FAA has not changed this AD as a result of this comment.

Conclusion

These products have been approved by the civil aviation authority of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, that authority has notified the FAA of the unsafe condition described in the MCAI referenced above. 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 NPRM. None of the changes will increase the economic burden on any operator.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed EASA AD 2025-0002, which specifies procedures for performing repetitive BSIs for cracks of the IP compressor VIGVs and applicable corrective actions. Corrective actions include, depending on the inspection findings, reduced inspection intervals for the repetitive BSIs or removal of the engine from service and replacement of the IP compressor VIGVs. 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.

Interim Action

The FAA considers that this AD is an interim action. If final action is later identified, the FAA might consider further rulemaking at that time.

Costs of Compliance

The FAA estimates that this AD affects 28 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 repairs that would be required based on the results of the inspection. The agency has no way of determining the number of engines that might need these replacements: ( printed page 52498)

Authority for This Rulemaking

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.

Regulatory Findings

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.

The Amendment

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