SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments using a method listed under the ADDRESSES section. Include “Docket No. FAA-2026-3874; Project Identifier MCAI-2025-01426-T” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, 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 proposal 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 NPRM.

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 NPRM 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 NPRM, 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 NPRM. Submissions containing CBI should be sent to Frank Carreras, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3539; email: Frank.Carreras@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

The FAA issued AD 2025-16-12, Amendment 39-23110 (90 FR 39102, August 14, 2025; corrected August 22, 2025 (90 FR 40964)) (AD 2025-16-12), for all Airbus SAS Model A319-151N, -153N, -171N, and -173N airplanes; Model A320-251N, -252N, -253N, -271N, -272N, and -273N airplanes; and Model A321-251N, -252N, -253N, -271N, -272N, -251NX, -252NX, -253NX, -271NX, -272NX, -253NY, and -271NY airplanes. AD 2025-16-12 was prompted by an MCAI originated by EASA, which is the Technical Agent for the Member States of the European Union. EASA issued AD 2025-0096, dated April 28, 2025 (EASA AD 2025-0096), to correct an unsafe condition. The MCAI states that occurrences were reported of HPV butterfly seal retention clip rupture, which causes the butterfly seals to no longer be retained in the butterfly groove. This may increase internal leakage, triggering an alert that the HPV has failed in the open condition. It may also release foreign object debris, which could damage the systems ( e.g., engine bleed air system and pneumatic system) downstream from the HPV on the engine pylon and wing.

The FAA issued AD 2025-16-12 to address high pressure and temperatures in the duct downstream from the pressure regulating valve, which could lead to duct burst and result in damage to several systems or the airframe and consequent loss of control of the airplane. AD 2025-16-12 requires revising the existing AFM and the existing FAA-approved MEL, allows replacement of each affected HPV as an optional terminating action, and prohibits the installation of affected parts.

Actions Since AD 2025-16-12 Was Issued

EASA AD 2025-0096 specifies to repetitively replace each affected HPV clip with another affected HPV clip. In the preamble to AD 2025-16-12, the FAA explained that adopting the repetitive replacement was considered, but the compliance times in EASA AD 2025-0096 for the repetitive replacement would allow enough time to provide the public the opportunity to comment on the merits of that requirement. Since the FAA issued AD 2025-16-12, the FAA has determined that repetitive replacement of the affected HPV clips is necessary to address the unsafe condition.

The FAA is proposing 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-2026-3874.

Explanation of Retained Requirements

Although this proposed AD does not explicitly restate the requirements of AD 2025-16-12, this proposed AD would retain all of the requirements of AD 2025-16-12. Those requirements are referenced in EASA AD 2025-0096, which, in turn, is referenced in paragraph (g) of this proposed AD.

Material Incorporated by Reference Under 1 CFR Part 51

This proposed AD would require EASA AD 2025-0096, which the Director of the Federal Register approved for incorporation by reference as of August 29, 2025 (90 FR 39102, August 14, 2025; corrected August 22, 2025 (90 FR 40964)). 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 NPRM after determining that the unsafe condition described previously is likely to exist or develop in other products of the same type design.

Proposed AD Requirements in This NPRM

This proposed AD would require revising the existing AFM to incorporate a temporary revision that provides the operational procedures the flight crew must apply in the case of an engine bleed overpressure; revising the existing FAA-approved MEL to provide dispatch procedures associated with the unsafe condition; and repetitively replacing each affected HPV clip with another affected HPV clip. This proposed AD would also prohibit the installation of affected parts. This proposed AD would allow replacement of each affected HPV as an optional terminating action for the ( printed page 23027) AFM and MEL revisions and repetitive replacement of the HPV clips.

Compliance With AFM and MEL Revisions

EASA AD 2025-0096 requires operators to “inform all flight crew” of revisions to the AFM and MEL, and thereafter to “operate the aeroplane accordingly.” However, this AD does not specifically require those actions as those actions are already required by FAA regulations. FAA regulations require operators furnish to pilots any changes to the AFM (for example, 14 CFR 121.137), and to ensure the pilots are familiar with the AFM (for example, 14 CFR 91.505). As with any other flightcrew training requirement, training on the updated AFM content is tracked by the operators and recorded in each pilot's training record, which is available for the FAA to review. FAA regulations also require pilots to follow the procedures in the existing AFM including all updates. Section 91.9 requires that any person operating a civil aircraft must comply with the operating limitations specified in the AFM. Section 121.628(a)(2) requires operators to provide pilots with access to all the information contained in the operator's MEL. Furthermore, 14 CFR 121.628(a)(5) requires airplanes to be operated under all applicable conditions and limitations contained in the operator's MEL. Therefore, including a requirement in this AD to operate the airplane according to the revised AFM and MEL would be redundant and unnecessary.

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, the FAA proposes to retain the incorporation by reference (IBR) of EASA AD 2025-0096. This proposed AD would, therefore, require compliance with EASA AD 2025-0096 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this proposed AD. Using common terms that are the same as the heading of a particular section in EASA AD 2025-0096 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 2025-0096. Material required by EASA AD 2025-0096 for compliance will be available at regulations.gov under Docket No. FAA-2026-3874 after the FAA final rule is published.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 554 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD:

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

The FAA determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 this proposed regulation:

(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.

The Proposed Amendment

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

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

2. The FAA amends § 39.13 by:

a. Removing Airworthiness Directive (AD) 2025-16-12, Amendment 39- ( printed page 23028) 23110 (90 FR 39102, August 14, 2025; corrected August 22, 2025 (90 FR 40964)); and

b. Adding the following new AD:

Airbus SAS: Docket No. FAA-2026-3874; Project Identifier MCAI-2025-01426-T.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by June 15, 2026.

(b) Affected ADs

This AD replaces AD 2025-16-12, Amendment 39-23110 (90 FR 39102, August 14, 2025; corrected August 22, 2025 (90 FR 40964)) (AD 2025-16-12).

(c) Applicability

This AD applies to all Airbus SAS airplanes identified in paragraphs (c)(1) through (3) of this AD, certificated in any category.

(1) Model A319-151N, -153N, -171N, and -173N airplanes.

(2) Model A320-251N, -252N, -253N, -271N, -272N, and -273N airplanes.

(3) Model A321-251N, -252N, -253N, -271N, -272N, -251NX, -252NX, -253NX, -271NX, -272NX, -253NY, and -271NY airplanes.

(d) Subject

Air Transport Association (ATA) of America Code 36, Pneumatic.

(e) Unsafe Condition

This AD was prompted by occurrences of high-pressure bleed valve (HPV) butterfly seal retention clip rupture. The FAA is issuing this AD to address high pressure and temperatures in the duct downstream from the pressure regulating valve, which could lead to duct burst and result in damage to several systems or the airframe and consequent loss of control of the airplane.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Requirements

Except as specified in paragraph (h) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, European Union Aviation Safety Agency (EASA) AD 2025-0096, dated April 28, 2025 (EASA AD 2025-0096).

(h) Exceptions to EASA AD 2025-0096

(1) Where paragraphs (1) and (6.2) of EASA AD 2025-0096 refer to its effective date, this AD requires August 29, 2025 (the effective date of AD 2025-16-12).

(2) Where paragraph (4) of EASA AD 2025-0096 refers to its effective date, this AD requires using the effective date of this AD.

(3) Where paragraphs (1) and (3) of EASA AD 2025-0096 specify to “inform all flight crews, and, thereafter, operate the aeroplane accordingly,” this AD does not require those actions as those actions are already required by existing FAA operating regulations (see 14 CFR 91.9, 91.505, 121.137, and 121.628(a)(2) and (a)(5)).

(4) Where paragraph (3) of EASA AD 2025-0096 specifies to “implement the instructions of the MMEL update, as applicable, depending on aeroplane configuration (see Note 1 of this AD), on the basis of which the operator's MEL must be amended”, this AD requires replacing that text with “revise the operator's existing FAA-approved MEL by incorporating the applicable information identified in “The MMEL update” as defined in EASA AD 2025-0096”.

(5) Where the service information required by EASA AD 2025-0096 specifies discarding parts, this AD requires removing those parts from service.

(6) This AD does not adopt the “Remarks” section of EASA AD 2025-0096.

(i) Additional AD Provisions

The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): the Manager, AIR-520, Continued Operational Safety Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or responsible Flight Standards Office, as appropriate. If sending information directly to the manager of the Continued Operational Safety Branch, send it to the attention of the person identified in paragraph (j)(1) of this AD and email to: AMOC@faa.gov. Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office.

(2) Contacting the Manufacturer: For any requirement in this AD to obtain instructions from a manufacturer, the instructions must be accomplished using a method approved by the Manager, AIR-520, Continued Operational Safety Branch, FAA; or EASA; or Airbus SAS's EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature.

(3) Required for Compliance (RC): Except as required by paragraph (i)(2) of this AD, if any material contains procedures or tests that are identified as RC, those procedures and tests must be done to comply with this AD; any procedures or tests that are not identified as RC are recommended. Those procedures and tests that are not identified as RC may be deviated from using accepted methods in accordance with the operator's maintenance or inspection program without obtaining approval of an AMOC, provided the procedures and tests identified as RC can be done and the airplane can be put back in an airworthy condition. Any substitutions or changes to procedures or tests identified as RC require approval of an AMOC.

(j) Additional Information

(1) For more information about this AD, contact Frank Carreras, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3539; email: Frank.Carreras@faa.gov.

(2) For Airbus material identified in this AD that is not incorporated by reference, contact Airbus SAS, Airworthiness Office—EIAS, Rond-Point Emile Dewoitine No: 2, 31700 Blagnac Cedex, France; telephone +33 5 61 93 36 96; fax +33 5 61 93 44 51; email account.airworth-eas@airbus.com; website airbus.com.

(k) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this material as applicable to do the actions required by this AD, unless this AD specifies otherwise.

(3) The following material was approved for IBR on August 29, 2025 (90 FR 39102, August 14, 2025; corrected August 22, 2025 (90 FR 40964)).

(i) European Union Aviation Safety Agency (EASA) AD 2025-0096, dated April 28, 2025.

(ii) [Reserved]

(4) For EASA material identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221 8999 000; email ADs@easa.europa.eu. You may find this material on the EASA website at ad.easa.europa.eu.

(5) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195.

(6) You may view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit www.archives.gov/​federal-register/​cfr/​ibr-locations or email fr.inspection@nara.gov.

91 FR 23025