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 ADDRESSES . Include “Docket No. FAA-2026-7230; Project Identifier MCAI-2026-00185-R” 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 the 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 Soban Saeed, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590. 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 2024-04-10, Amendment 39-22689 (89 FR 15431, March 4, 2024) (AD 2024-04-10), for all AHD Model EC135P1, EC135P2, EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, EC135T3, and EC635T2+ helicopters. AD 2024-04-10 was prompted by EASA Emergency AD 2024-0028-E, dated January 25, 2024, (EASA Emergency AD 2024-0028-E) originated by EASA, which is the Technical Agent for the Member States of the European Union. EASA issued EASA Emergency AD 2024-0028-E to correct an unsafe condition identified as cracks in affected T/R blades. EASA then superseded EASA Emergency AD 2024-0028-E and issued EASA AD 2024-0028R1, dated April 22, 2024 (EASA AD 2024-0028R1), to allow an optional visual inspection (Method E). The FAA did not issue an AD corresponding to EASA AD 2024-0028R1.

AD 2024-04-10 requires repetitively inspecting T/R blades having part number (P/N) L642A2002111 or P/N L642A2002112 installed for a crack and, depending on the results, removing any cracked T/R blade from service. AD 2024-04-10 also prohibits installing certain T/R blades on any helicopter unless certain requirements are met. ( printed page 47995) The FAA issued AD 2024-04-10 to detect and address cracks in affected T/R blades. The unsafe condition, if not addressed, could result in separation of a T/R blade assembly and subsequent reduced control of the helicopter.

Actions Since AD 2024-04-10 Was Issued

Since the FAA issued AD 2024-04-10, EASA superseded EASA AD 2024-0028R1 and issued EASA AD 2026-0032, dated February 19, 2026 (EASA AD 2026-0032) (also referred to as the MCAI). The MCAI states that a determination was made by the manufacturer that a previously approved inspection method (Method A), should be discontinued. Method A consisted of a dye-penetrant (with increased temperature) inspection.

In addition, since the FAA issued AD 2024-04-10, it has been determined that TRB assemblies with P/N L642A2002121 installed, may also be subject to intergranular corrosion and could contain or develop the same unsafe condition. The FAA may publish a separate rulemaking to address this part number.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-7230.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed EASA AD 2026-0032, which specifies procedures for repetitively inspecting the affected TRB assembly for cracks and, if any crack is detected, replacing the affected TRB assembly with a serviceable part. EASA AD 2026-0032 prohibits installing a certain TRB assembly on any helicopter unless certain requirements are met and specifies that replacing an affected TRB assembly with an eligible TRB assembly that is not an affected part is terminating action for certain repetitive inspections.

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 (CAA) 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 on other products of the same type design.

Proposed AD Requirements in This NPRM

This proposed AD would retain the requirements of AD 2024-04-10 and would also require accomplishing the actions specified in EASA AD 2026-0032, described previously, as incorporated by reference, except for any differences identified as exceptions in the regulatory text of this AD. See “Differences Between this Proposed AD and the MCAI” for a discussion of the general differences included in this proposed AD.

Differences Between This Proposed AD and the MCAI

The MCAI applies to Airbus Helicopters Model EC635 P2+, EC635 P3, EC635 T1, and EC635 T3 helicopters, whereas this proposed AD does not because those models do not have an FAA type certificate.

The MCAI specifies inspecting for cracks by performing a visual inspection, dye-penetrant inspection, eddy current inspection, or fluorescent penetrant inspection, whereas this proposed AD would require inspection methods under certain scenarios as outlined in the regulatory text of this proposed AD, which are also described in a Note in the regulatory text of this proposed 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 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 incorporate EASA AD 2026-0032 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with EASA AD 2026-0032 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 2026-0032 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 2026-0032. Material required by EASA AD 2026-0032 for compliance will be available at regulations.gov under Docket No. FAA-2026-7230 after the FAA final rule is published.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 359 helicopters of U.S. registry.

The FAA estimates the following costs to comply with this proposed AD:

The FAA estimates the following costs to do any replacements that would be required based on the results of the proposed inspection. The agency has no way of determining the number of helicopters that might need this replacement:

( printed page 47996)

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 that the 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 2024-04-10, Amendment 39-22689 ( 89 FR 15431, March 4, 2024); and

b. Adding the following new airworthiness directive:

Airbus Helicopters Deutschland GmbH (AHD): Docket No. FAA-2026-7230; Project Identifier MCAI-2026-00185-R.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by September 14, 2026.

(b) Affected ADs

This AD replaces AD 2024-04-10, Amendment 39-22689 (89 FR 15431, March 4, 2024) (AD 2024-04-10).

(c) Applicability

This AD applies to all Airbus Helicopters Deutschland GmbH (AHD) Model EC135P1, EC135P2, EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, EC135T3, and EC635T2+ helicopters, certificated in any category.

(d) Subject

Joint Aircraft System Component (JASC) Code 6410, Tail rotor blades.

(e) Unsafe Condition

This AD was prompted by a report of a separated tail rotor blade (TRB) assembly due to a crack in the TRB assembly caused by intergranular corrosion. The FAA is issuing this AD to detect and address cracks in the TRB assembly. The unsafe condition, if not addressed, could result in separation of the TRB assembly and reduced control of the helicopter.

(f) Compliance

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

(g) Requirements

Except as specified in paragraphs (h) and (i) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, European Union Aviation Safety Agency AD 2026-0032, dated February 19, 2026 (EASA AD 2026-0032).

(h) Exceptions to EASA AD 2026-0032

(1) Where EASA AD 2026-0032 refers to its effective date, this AD requires using the effective date of this AD.

(2) Where EASA AD 2026-0032 refers to January 29, 2024 (the effective date of EASA Emergency AD 2024-0028-E), this AD requires using March 19, 2024 (the effective date of AD 2024-04-10).

(3) Where EASA AD 2026-0032 refers to flight hours, this AD requires using hours time-in-service (TIS).

(4) Where paragraph (1) of EASA AD 2026-0032 specifies “Before an affected part exceeds 685 FH [flight hours] since first installation on a helicopter”, this AD requires replacing that text with “Before an affected part accumulates 685 hours TIS since first installation on a helicopter, or within 10 hours TIS after March 19, 2024 (the effective date of AD 2024-04-10), whichever occurs later”.

(5) Where paragraph 4.3 of the material referenced in EASA AD 2026-0032 recommends type II visible dye inspections, this AD requires the inspection methods in paragraphs (h)(5)(i), (ii), or (iii) of this AD, as applicable:

(i) If the affected part has previously been inspected using a type II visible dye method, perform type II visible dye (Method B of the material referenced in EASA AD 2026-0032) or eddy current inspections, instead of fluorescent penetrant inspections.

(ii) If the affected part has not previously been inspected using a type II visible dye inspection, perform eddy current or fluorescent penetrant inspections, instead of type II visible dye inspections.

(iii) If you cannot determine whether the affected part has previously been inspected by a type II visible dye method, clean all surfaces to be inspected and perform an eddy current or a fluorescent penetrant inspection, instead of a type II visible dye inspection.

Note 1 to paragraph (h)(5): The FAA reminds operators of the airworthiness concern regarding type II visible dye inspections of critical parts discussed in FAA Special Airworthiness Information Bulletin (SAIB) CE-18-26R1, dated October 30, 2018 (SAIB CE-18-26R1). SAIB CE-18-26R1 explains the risks associated with using type II visible dye inspection methods, including the prohibition in ASTM E1417 on the use of type II visible dye penetrant prior to the use of type I fluorescent penetrant on the same surface. SAIB CE-18-26R1 also advises of the importance of pre- and post-inspection cleaning to ensure proper detection of cracks. You can find SAIB CE-18-26R1 at drs.faa.gov.

Note 2 to paragraph (h)(5): The material referenced in EASA AD 2026-0032 identifies a type II visible dye inspection as Method A (not allowed), or Method B, eddy current inspection as Method C; and fluorescent penetrant inspection as Method D.

Note 3 to paragraph (h)(5): When entering compliance with the applicable paragraph of the AD into the helicopter maintenance records, documenting that a type II visible dye inspection was performed improves the accuracy of maintenance records.

(6) This AD does not adopt paragraph (3) of EASA AD 2026-0032.

(7) This AD does not adopt the “Remarks” section of EASA AD 2026-0032.

(i) No Reporting or Returning of Parts

Where the material referenced in EASA AD 2026-0032 specifies to submit certain information and to send removed parts to the manufacturer, this AD does not include those actions.

(j) Special Flight Permits

Special flight permits, as described in 14 CFR 21.197 and 21.199, are not allowed.

(k) Alternative Methods of Compliance (AMOCs)

(1) The Manager, International Validation 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 District Office, ( printed page 47997) as appropriate. If sending information directly to the manager of the International Validation Branch, send it to the attention of the person identified in paragraph (l) of this AD and email to AMOC@faa.gov.

(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office.

(l) Additional Information

For more information about this AD, contact Soban Saeed, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316) 946-4123; email: soban.saeed@faa.gov.

(m) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference 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 the AD specifies otherwise.

(i) European Union Aviation Safety Agency (EASA) AD 2026-0032, dated February 19, 2026.

(ii) [Reserved]

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

(4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 10101 Hillwood Parkway, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110.

(5) 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 47994