SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2020-06-16, Amendment 39-19885 (85 FR 17738, March 31, 2020) (AD 2020-06-16). AD 2020-06-16 applied to certain RRD Model RB211 Trent 768-60, 772-60, and 772B-60 engines. AD 2020-06-16 required initial and repetitive UIs of the affected LPC blades and, depending on the results of the UIs, replacement with a part eligible for installation. The FAA ( printed page 57783) issued AD 2020-06-16 to prevent LPC blade airfoil separation.

The NPRM was published in the Federal Register on March 3, 2026 (91 FR 10349). The NPRM was prompted by EASA AD 2025-0144, dated July 9, 2025 (EASA AD 2025-0144) (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 occurrences have been reported of LPC partial airfoil blade release events on RRD Model Trent 700 engines. The MCAI also states that RRD issued updated service material providing improvements to the ultrasonic inspection procedures and updated initial inspection compliance times.

In the NPRM, the FAA proposed to continue to require initial and repetitive UIs of the affected LPC blades for sub-surface anomalies and, depending on the results of the UIs, replacement with a part eligible for installation.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-2287.

Discussion of Final Airworthiness Directive

Comments

The FAA received comments from two commenters. Commenters included the Air Line Pilots Association, International (ALPA) and an anonymous commenter. ALPA supported the NPRM without change. The following presents the comments received on the NPRM and the FAA's response to each comment.

Request To Clarify Reporting Requirement

An individual commenter requested that the FAA clarify why paragraph (i) of the proposed AD eliminates the manufacturer's reporting requirement, including identifying what specific data elements are collected under the EASA AD specifications and whether the data is used by RRD to monitor fleet-wide anomaly rates, refine inspection intervals, or update service instructions. The commenter stated that the NPRM removes the requirement to submit inspection findings to RRD but does not describe the content of that requirement or provide any reasoned explanation for its omission. The commenter also stated that if the reporting requirement supports fleet-level surveillance or service bulletin development, its omission would disrupt the data feedback loop and reduce the completeness of data available to the manufacturer. The commenter asserted that if the requirement does not serve these functions, the FAA should explicitly state as much.

The FAA disagrees with the request. The FAA normally requires reporting if the results are needed to determine the scope of the identified unsafe condition or to develop future corrective actions. For this AD, reporting is not necessary as the inspection and replacement of the LPC blade addresses the unsafe condition. Operators are encouraged to voluntarily submit data to RRD by normal processes. The FAA did not change this AD as a result of this comment.

Request To Clarify Effective Date Exception

An individual commenter requested that the FAA clarify why paragraph (h)(1) of the proposed AD substitutes the effective date of the FAA AD for all references to the effective date of EASA AD 2025-0144. The commenter stated that the FAA should not replace EASA AD effective dates with FAA AD effective dates without identifying how EASA AD 2025-0144 measures its compliance times, the resulting inspection deadlines under both effective dates, and whether any affected engines would operate longer before initial inspection under the FAA rule than under the EASA AD specifications. The commenter noted that compliance times are date-relative and substitution of the FAA AD effective date extends the initial inspection window for U.S.-registered engines relative to the EASA AD specifications. The commenter asserted that without this comparison, the record does not demonstrate that the proposed framework avoids a timing gap for a known blade release hazard or maintains equivalence with EASA's safety intent.

The FAA acknowledges the commenter's concerns and clarifies that FAA standard procedure is to reference the FAA AD effective date rather than the EASA AD effective date because applying the EASA effective date would impose retroactive compliance requirements and could place operators in immediate noncompliance upon issuance of the FAA AD. The use of the FAA AD effective date rather than the EASA AD effective date prevents grounding of airplanes that are above the threshold while still allowing for an acceptable level of safety. The FAA did not change this AD as a result of this comment.

Request To Clarify Retainment of Affected Part Numbers

An individual commenter requested that the FAA clarify whether part numbers FK25441, FK25968, FW11901, and FW15393, which were removed from the applicability of EASA AD 2025-0144, are currently installed on U.S.-registered engines and, if so, identify the estimated number of affected engines or parts. The commenter stated that if the FAA lacks current installation data at the part-number level, it should consult RRD service records or require operators to report current installation status as part of the initial compliance action, rather than imposing indefinite regulatory applicability on parts that may no longer be in service.

The FAA disagrees with request because the unsafe condition applies to part numbers FK25441, FK25968, FW11901, and FW15393, regardless of whether they are currently in service or not. The LPC blades are rotable parts that can be later installed in engines. The FAA did not change 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 2025-0144, which specifies procedures for performing an ultrasonic inspection of the LPC blade for sub-surface anomalies, and replacement, if necessary.

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.

Differences Between This AD and the MCAI

Where EASA AD 2025-0144 applies to RRD Model RB211 Trent 772C-60 engines, this AD does not, as these engines do not have an FAA type certificate.

Where EASA AD 2025-0144 removes LPC part numbers FK25441, FK25968, ( printed page 57784) FW11901, and FW15393 from the affected parts list, this AD includes these part numbers in the applicability in the event that any of these parts remain in service.

Costs of Compliance

The FAA estimates that this AD affects 140 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 inspection. The agency has no way of determining the number of engines that might need these replacements:

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: