SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written data, views, or arguments about this final rule. Send your comments using a method listed under the ADDRESSES section. Include “Docket No. FAA-2026-8792; Project Identifier MCAI-2025-01180-T” at the beginning of your comments. The most helpful comments reference a specific portion of the final rule, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this final rule because of those comments.

Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this final rule.

Confidential Business Information

CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this AD contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this final rule, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this final rule. Submissions containing CBI should be sent to Fatin Saumik, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: 516-228-7350; email: 9-AVS-AIR-BACO-COS@faa.gov. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.

Background

EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2025-0135, dated June 26, 2025 (EASA AD 2025-0135) (also referred to as the MCAI), to correct an unsafe condition on certain ATR-GIE Avions de Transport Régional Model ATR42-400 and -500 airplanes. Model ATR42-400 airplanes are not certificated by the FAA and are not included on the U.S. type certificate data sheet; this AD therefore does not include those airplanes in the applicability. The MCAI states a new airworthiness limitation has been developed. This new airworthiness limitation is contained in Temporary Revision 18.9 of ATR42-400/-500 Time Limits Document (TLD), dated April 9, 2025 (TR 18.9).

The FAA is issuing this AD to address the inability to close the ventilation electrical shut-off valves in case of annunciated smoke in a Class E cargo compartment, which could allow suppressed fire to reignite and further propagate. This condition, if not addressed, could result in an uncontrolled fire in the cargo compartment.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-8792.

Other Relevant Rulemaking

EASA AD 2025-0135 refers to EASA AD 2024-0052, dated February 23, 2024 (EASA AD 2024-0052); EASA AD 2025-0005, dated January 7, 2025 (EASA AD 2025-0005); and AD 2025-0045, dated February 19, 2025 (EASA AD 2025-0045); which were previously issued to require the airworthiness limitations in ATR42-400/-500 TLD, Revision 18, dated October 16, 2023; TR 18.1 of ATR42-400/-500 TLD, dated July 30, 2024; and TR 18.3 of ATR42-400/-500 TLD, dated November 22, 2024; respectively. The FAA issued AD 2024-19-02, Amendment 39-22844 (89 FR 82491, October 11, 2024) (AD 2024-19-02); AD 2025-25-10, Amendment 39-23218 (91 FR 202, January 5, 2026) (AD ( printed page 56585) 2025-25-10); and AD 2026-10-08, Amendment 39-23348 (91 FR 31353, May 27, 2026) (AD 2026-10-08); to adopt the requirements of EASA AD 2024-0052, EASA AD 2025-0005, EASA AD 2025-0045, respectively. The FAA reviewed all the relevant service information and determined that revising the existing maintenance or inspection program, as applicable, to incorporate the new airworthiness limitations in EASA AD 2025-0135 as referenced in TR 18.9 would not affect compliance with FAA AD 2024-19-02, AD 2025-25-10, and AD 2026-10-08.

Material Incorporated by Reference Under 1 CFR Part 51

EASA AD 2025-0135 specifies a new airworthiness limitation for performing repetitive operational tests of the air conditioning ( i.e., ventilation electrical) shut-off valves.

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.

FAA's Determination

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 is issuing this AD after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.

AD Requirements

This AD requires revising the existing maintenance or inspection program, as applicable, to incorporate a new airworthiness limitation, which is specified in EASA AD 2025-0135 described previously, as incorporated by reference. Any differences with EASA AD 2025-0135 are identified as exceptions in the regulatory text of this AD.

This AD requires revisions to certain operator maintenance documents to include new actions ( e.g., inspections). Compliance with these actions is required by 14 CFR 91.403(c). For airplanes that have been previously modified, altered, or repaired in the areas addressed by this AD, the operator may not be able to accomplish the actions described in the revisions. In this situation, to comply with 14 CFR 91.403(c), the operator must request approval for an alternative method of compliance (AMOC) according to paragraph (j)(1) of this AD.

Explanation of Required Compliance Information

In the FAA's ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some civil aviation authority (CAA) ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. The FAA has been coordinating this process with manufacturers and CAAs. As a result, EASA AD 2025-0135 is incorporated by reference in this AD. This AD requires compliance with EASA AD 2025-0135 through that incorporation, except for any differences identified as exceptions in the regulatory text of this AD. Using common terms that are the same as the heading of a particular section in EASA AD 2025-0135 does not mean that operators need comply only with that section. For example, where the AD requirement refers to “all required actions and compliance times,” compliance with this AD requirement is not limited to the section titled “Required Action(s) and Compliance Time(s)” in EASA AD 2025-0135. Material required by EASA AD 2025-0135 for compliance will be available at regulations.gov under Docket No. FAA-2026-8792 after this final rule is published.

Airworthiness Limitation ADs Using the New Process

The FAA's process of incorporating by reference MCAI ADs as the primary source of information for compliance with corresponding FAA ADs has been limited to certain MCAI ADs (primarily those with service bulletins as the primary source of information for accomplishing the actions required by the FAA AD). However, the FAA is now expanding the process to include MCAI ADs that require a change to airworthiness limitation documents, such as airworthiness limitation sections.

For these ADs that incorporate by reference an MCAI AD that changes airworthiness limitations, the FAA requirements are unchanged. Operators must revise the existing maintenance or inspection program, as applicable, to incorporate the information specified in the new airworthiness limitation document. The airworthiness limitations must be followed according to 14 CFR 91.403(c) and 91.409(e).

The previous format of the airworthiness limitation ADs included a paragraph that specified that no alternative actions ( e.g., inspections or intervals) may be used unless the actions and intervals are approved as an AMOC in accordance with the procedures specified in the AMOCs paragraph under “Additional AD Provisions.” This new format includes a “Provisions for Alternative Actions and Intervals” paragraph that does not specifically refer to AMOCs, but operators may still request an AMOC to use an alternative action or interval.

Justification for Immediate Adoption and Determination of the Effective Date

Section 553(b) of the Administrative Procedure Act (APA) (5 U.S.C. 551 et seq.) authorizes agencies to dispense with notice and comment procedures for rules when the agency, for “good cause,” finds that those procedures are “impracticable, unnecessary, or contrary to the public interest.” Under this section, an agency, upon finding good cause, may issue a final rule without providing notice and seeking comment prior to issuance. Further, section 553(d) of the APA authorizes agencies to make rules effective in less than thirty days, upon a finding of good cause.

There are currently no domestic operators of these products. Accordingly, notice and opportunity for prior public comment are unnecessary, pursuant to 5 U.S.C. 553(b). In addition, for the foregoing reason(s), the FAA finds that good cause exists pursuant to 5 U.S.C. 553(d) for making this amendment effective in less than 30 days.

Regulatory Flexibility Act

The requirements of the Regulatory Flexibility Act (RFA) do not apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and comment. Because the FAA has determined that it has good cause to adopt this rule without notice and comment, RFA analysis is not required.

Costs of Compliance

Currently, there are no affected U.S.-registered airplanes. For any affected airplane that may be imported and placed on the U.S. Register in the future, the FAA provides the following cost estimates to comply with this AD:

The FAA has determined that revising the existing maintenance or inspection program takes an average of 90 work-hours per operator, although the agency recognizes that this number may vary from operator to operator. Since operators incorporate maintenance or inspection program changes for their affected fleet(s), the FAA has determined that a per-operator estimate ( printed page 56586) is more accurate than a per-airplane estimate.

The FAA estimates the total cost per operator for the new actions to be $7,650 (90 work-hours × $85 per work-hour).

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, and

(2) Will not affect intrastate aviation in Alaska.

The Amendment

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