Airworthiness Directives; Airbus Helicopters Deutschland GmbH (AHD) Helicopters

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2026-4656; Project Identifier MCAI-2026-00214-R]

RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters Deutschland GmbH (AHD) Helicopters

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for all Airbus Helicopters Deutschland GmbH (AHD) Model EC135P1, EC135P2, EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, EC135T3, and EC635T2+ helicopters. This proposed AD was prompted by a report of a separated tail rotor blade (TRB) assembly due to a crack caused by intergranular corrosion. This proposed AD would require repetitively inspecting a certain TRB assembly for cracks and, depending on the results, removing any cracked TRB assembly from service and replacing an affected part as terminating action for the repetitive inspections. This proposed AD would also prohibit installing a certain TRB assembly on any helicopter unless certain requirements are met. The FAA is proposing this AD to address the unsafe condition on these products.

DATES:

The FAA must receive comments on this NPRM by August 13, 2026.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

•

Federal eRulemaking Portal:

Go to

regulations.gov

. Follow the instructions for submitting comments.

•

Fax:

(202) 493-2251.

•

Mail:

U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

•

Hand Delivery:

Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

AD Docket:

You may examine the AD docket at

regulations.gov

under Docket No. FAA-2026-4656; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this NPRM, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The street address for Docket Operations is listed above.

Material Incorporated by Reference:

• For European Union Aviation Safety Agency (EASA) material identified in this proposed 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.

• 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.

FOR FURTHER INFORMATION CONTACT:

Soban Saeed, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316) 946-4123; email:

soban.saeed@faa.gov.

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-2026-4656; Project Identifier MCAI-2026-00214-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 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 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), which applies to all AHD Model EC135P1, EC135P2, EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, EC135T3, and EC635T2+ helicopters. AD 2024-04-10 requires repetitively inspecting TRBs having part number (P/N) L642A2002111 or P/N L642A2002112 installed, for cracks and, depending on the results, removing any cracked TRB from service. AD 2024-04-10 also prohibits installing certain TRBs on any helicopter unless certain requirements are met. AD 2024-04-10 was prompted by a report of a separated TRB due to a crack caused by intergranular corrosion.

Since the FAA issued AD 2024-04-10, it has been determined that TRBs with P/N L642A2002121 installed, may also be subject to intergranular corrosion and could contain or develop the same unsafe condition.

To address this condition, EASA, which is the Technical Agent for the Member States of the European Union, issued EASA AD 2025-0113, dated May 15, 2025, to address TRB assemblies having P/N L642A2002121 being subject to intergranular corrosion. EASA then superseded EASA AD 2025-0113 and issued EASA AD 2026-0031, dated February 19, 2026 (EASA AD 2026-0031) (also referred to as the MCAI), for all AHD Model EC135 P1, EC135 P2, EC135 P2+, EC135 P3, EC135 T1, EC135 T2, EC135 T2+, EC135 T3, EC635 P2+, EC635 P3, EC635 T1, EC635 T2+, and EC635 T3 helicopters. The MCAI states an occurrence was reported of increased

vibrations of the tail rotor, which was the result of a crack on the TRB assembly. Further investigation revealed that the affected parts may be subject to intergranular corrosion, which could lead to cracks. The MCAI also states that a determination was made by the manufacturer that a previously approved inspection method (Method A), which was in a previously issued MCAI, should be discontinued. Method A consisted of dye-penetrant (with increased temperature) inspection. The FAA did not issue an AD corresponding to EASA AD 2025-0113.

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.

You may examine the MCAI in the AD docket at

regulations.gov

under Docket No. FAA-2026-4656.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed EASA AD 2026-0031, 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 2026-0031 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 require accomplishing the actions specified in EASA AD 2026-0031, 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 AD does not because those models do not have an FAA type certificate.

The MCAI specifies inspecting for cracks by performing dye-penetrant inspection, eddy current inspection, or fluorescent penetrant inspection, whereas this AD would require inspection methods under certain scenarios as outlined in the regulatory text of the 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 2026-0031 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with EASA AD 2026-0031 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 2026-0031 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 2026-0031. Material required by EASA AD 2026-0031 for compliance will be available at

regulations.gov

under Docket No. FAA-2026-4656 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:

Estimated costs

Action

Labor cost

Parts cost

Cost per

product

Cost on

U.S. operators

Inspect one affected TRB assembly (up to 10 per helicopter)

3 work-hours × $85 per hour = $255

$50

Up to $305

Up to $109,495.

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:

On-condition costs

Action

Labor cost

Parts cost

Cost per product

Replace one TRB assembly (up to 10 per helicopter)

3 work-hours × $85 per hour = $255

$4,900 per TRB assembly

Up to $51,550.

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.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

The Proposed Amendment

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

PART 39—AIRWORTHINESS DIRECTIVES

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

Authority:

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

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive:

Airbus Helicopters Deutschland GmbH (AHD):

Docket No. FAA-2026-4656; Project Identifier MCAI-2026-00214-R.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by August 13, 2026.

(b) Affected ADs

None.

(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 2026-0031, dated February 19, 2026 (EASA AD 2026-0031).

(h) Exceptions to EASA AD 2026-0031

(1) Where EASA AD 2026-0031 refers to its effective date, this AD requires using the effective date of this AD.

(2) Where EASA AD 2026-0031 refers to flight hours, this AD requires using hours time-in-service (TIS).

(3) Where paragraph (1) of EASA AD 2026-0031 specifies “Before an affected part exceeds 1432 FH [flight hours] since first installation on a helicopter”, this AD requires replacing that text with “Before an affected part accumulates 1,432 hours TIS since first installation on a helicopter, or within 10 hours TIS after the effective date of this AD, whichever occurs later”.

(4) Where paragraph 4.3 of the material referenced in EASA AD 2026-0031 recommends type II visible dye inspections, this AD requires the inspection methods in paragraphs (h)(4)(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 2026-0031) 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)(4):

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 American Society for Testing and Materials (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)(4):

The material referenced in EASA AD 2026-0031 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)(4):

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.

(5) This AD does not adopt paragraphs (3) and (7) of EASA AD 2026-0031.

(6) This AD does not adopt the “Remarks” section of EASA AD 2026-0031.

(i) No Reporting or Returning of Parts

Where the material referenced in EASA AD 2026-0031 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, 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 2026-0031, 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.

Issued on June 24, 2026.

Christopher R. Parker,

Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.

[FR Doc. 2026-13034 Filed 6-26-26; 8:45 am]

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