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Proposed Rule2026-10256

Airworthiness Directives; Airbus Helicopters

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Published

May 22, 2026

Issuing agencies

Transportation DepartmentFederal Aviation Administration

Abstract

The FAA proposes to supersede Airworthiness Directive (AD) 2023-25-14, which applies to certain Airbus Helicopters Model EC130T2 helicopters. AD 2023-25-14 revises the procedures for inspecting the vibration level on the tail rotor drive shaft and, depending on these results, requires replacing certain parts. Since the FAA issued AD 2023-25-14, the manufacturer developed a modification of the rear drive shaft, sliding flange and equipped splined sleeve. This proposed AD would require installing this modification and repetitively inspecting the vibration level of the tail rotor drive shaft. This proposed AD would also prohibit the installation of certain parts and prohibit the performance of a balance correction unless certain requirements are met. The FAA is proposing this AD to address the unsafe condition on these products.

Full Text

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<title>Federal Register, Volume 91 Issue 99 (Friday, May 22, 2026)</title>
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[Federal Register Volume 91, Number 99 (Friday, May 22, 2026)]
[Proposed Rules]
[Pages 30257-30260]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-10256]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2026-4644; Project Identifier MCAI-2024-00418-R]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2023-25-14, which applies to certain Airbus Helicopters Model EC130T2
helicopters. AD 2023-25-14 revises the procedures for inspecting the
vibration level on the tail rotor drive shaft and, depending on these
results, requires replacing certain parts. Since the FAA issued AD
2023-25-14, the manufacturer developed a modification of the rear drive
shaft, sliding flange and equipped splined sleeve. This proposed AD
would require installing this modification and repetitively inspecting
the vibration level of the tail rotor drive shaft. This proposed AD
would also prohibit the installation of certain parts and prohibit the
performance of a balance correction 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 July 6, 2026.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="http://regulations.gov">regulations.gov</a>. Follow
the instructions for submitting comments.
<bullet> Fax: (202) 493-2251.
<bullet> 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.
<bullet> 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 <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2026-4644; 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:
<bullet> For European Union Aviation Safety Agency (EASA) material
identified in this proposed AD, contact EASA, Konrad-Adenauer-Ufer 3,
50668 Cologne, Germany; telephone +49 221 8999 000; email
<a href="/cdn-cgi/l/email-protection#2e6f6a5d6e4b4f5d4f004b5b5c415e4f004b5b">[email&#160;protected]</a>; You may find this material on the website
ad.easa.europa.eu.
<bullet> 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: Eric Rivera, Aviation Safety Engineer,
FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (773)
412-9048; email: <a href="/cdn-cgi/l/email-protection#90f5e2f9f3bee2f9e6f5e2f1a0a1d0f6f1f1bef7ffe6">[email&#160;protected]</a>.

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-2026-4644; Project Identifier
MCAI-2024-00418-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
<a href="http://regulations.gov">regulations.gov</a>, 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 Eric
Rivera, 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 2023-25-14, Amendment 39-22641 (88 FR 89568,
December 28, 2023) (AD 2023-25-14), for certain Airbus Helicopters
Model EC130T2 helicopters. AD 2023-25-14 was prompted by an MCAI
originated by EASA, which is the Technical Agent for the Member States
of the European Union. EASA issued EASA Emergency AD 2023-0190-E, dated
November 2, 2023 (EASA Emergency AD 2023-0190-E) to correct an unsafe
condition identified as excessive vibration level on the tail rotor
drive shaft, which could result in failure of the tail rotor drive
shaft and subsequent loss of yaw control of the helicopter.
AD 2023-25-14 requires repetitively checking the balancing of the
tail rotor drive shaft by measuring the vibration level. Depending on
the results, AD 2023-25-14 requires replacing certain parts with new
parts. AD 2023-25-14 prohibits installing certain part-numbered tail
rotor drive shafts on any helicopter unless its requirements are met.
The FAA issued AD 2023-25-14 to address an excessive vibration level on
the tail rotor drive shaft. The unsafe condition, if not addressed,
could result

[[Page 30258]]

in failure of the tail rotor drive shaft and loss of yaw control of the
helicopter.

Actions Since AD 2023-25-14 Was Issued

Since the FAA issued AD 2023-25-14, EASA superseded EASA Emergency
AD 2023-0190-E and issued EASA AD 2023-0190R1, dated February 20, 2024
(EASA AD 2023-0190R1). EASA AD 2023-0190R1 states a determination was
made that a used equipped splined sleeve and sliding flange may be
installed provided certain conditions are met. EASA then superseded
EASA AD 2023-0190R1 and issued EASA AD 2024-0144, dated July 19, 2024
(EASA AD 2024-0144) (also referred to as the MCAI). The MCAI states
that since EASA AD 2023-0190R1 was issued, the manufacturer developed a
modification consisting of a new rear rotor drive shaft, a new sliding
flange, and a new equipped splined sleeve, and that while these parts
are less susceptible to cracks, insufficient data is available to treat
them as terminating action for that AD's repetitive actions. In
addition, EASA AD 2024-0144 expands the list of affected part numbers
to include the new modified parts.
Since the issuance of AD 2023-25-14, the FAA also received a
comment from Airbus Helicopters who requested changes to the actions of
AD 2023-25-14, specifically in regard to the prohibition of performing
a balance correction. The comment disposition below explains and
addresses this comment.
The FAA is proposing this AD to continue to address excessive
vibration level on the tail rotor drive shaft. The unsafe condition, if
not addressed, could result in failure of the tail rotor drive shaft
and loss of yaw control of the helicopter.
You may examine the MCAI in the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2026-4644.

Comment on AD 2023-25-14

The FAA gave the public the opportunity to comment on AD 2023-25-
14. The following presents the comment received on AD 2023-25-14 and
the FAA's response to the comment.

Request To Require the Prohibition of Balance Correction

Airbus Helicopters requested that the FAA revise AD 2023-25-14 to
keep the EASA Emergency AD 2023-0190-E and associated Airbus
Helicopters EASB 05A042 Revision 1 requirement to prohibit performing a
balance correction, except if it is accomplished before next flight
after replacing the sliding flange and the equipped splined sleeve.
The FAA agrees. The FAA determined that the balance correction
prohibition was incorrectly interpreted to refer to the accomplishment
of a future action or maintenance task which is not an FAA enforceable
action. This proposed AD includes the prohibition.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed EASA AD 2024-0144, which specifies procedures for
repetitively checking the balancing of the tail rotor drive shaft by
measuring the vibration level and, depending on the results, replacing
certain parts with either used, new, or modified parts. EASA AD 2024-
0144 also prohibits performing a balance correction unless this action
is performed concurrently with replacing certain parts. If a balance
correction has already been performed independently of replacing those
parts, EASA AD 2024-0144 specifies contacting Airbus Helicopters to
obtain approved instructions and accomplishing those instructions. EASA
AD 2024-0144 also specifies reporting the vibration measurements to
Airbus Helicopters and installing modified rear drive shaft, sliding
flange, and equipped splined sleeve parts. Lastly, EASA AD 2024-0144
prohibits installing certain part-numbered tail rotor drive shafts,
sliding flanges, or equipped splined sleeves on any helicopter.
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 requires accomplishing the actions specified in
EASA AD 2024-0144, 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

For helicopters that accomplished a balance correction in
accordance with the instructions of the applicable aircraft maintenance
manual (AMM) before the effective date of EASA AD 2024-0144, except if
this balance correction was accomplished before next flight after
replacing the sliding flange and the equipped splined sleeve, EASA AD
2024-0144 requires contacting AH [Airbus Helicopters] to obtain
approved instructions, and within the compliance time(s) specified
therein, accomplishing those instructions accordingly. Whereas, for
helicopters that accomplished a balance correction in accordance with
the instructions of the applicable AMM before the effective date of
this proposed AD, except those that accomplished a balance correction
before the next flight after installing a new (zero total hours time-
in-service) sliding flange and a new (zero total hours time-in-service)
equipped splined sleeve, this proposed AD requires corrective action
accomplished in accordance with a method approved by the FAA, EASA, or
Airbus Helicopters' EASA Design Organization Approval.

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 2024-0144 by reference in the FAA final rule. This proposed AD
would, therefore, require compliance with EASA AD 2024-0144 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 2024-0144 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 2024-0144. Material required by
EASA AD 2024-0144 for compliance will be available at

[[Page 30259]]

<a href="http://regulations.gov">regulations.gov</a> under Docket FAA-2026-4644 after the FAA final rule is
published.

Interim Action

The FAA considers that this proposed AD would be an interim action.
If final action is later identified, the FAA might consider further
rulemaking then.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 108 helicopters of U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD:

Estimated Costs
----------------------------------------------------------------------------------------------------------------
Cost per Cost on U.S.
Action Labor cost Parts cost product operators
----------------------------------------------------------------------------------------------------------------
Vibration level inspection............ 1 work-hour x $85 per $0 $85 $9,180
hour = $85.
Install modified sliding flange, 8 work-hours x $85 per 61,716 62,396 6,738,768
equipped splined sleeve, and rear hour = $680.
rotor drive shaft.
----------------------------------------------------------------------------------------------------------------

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 these replacements:

On-Condition Costs
----------------------------------------------------------------------------------------------------------------
Cost per
Action Labor cost Parts cost product
----------------------------------------------------------------------------------------------------------------
Replace sliding flange and equipped splined 8 work-hours x $85 per hour = $72,749 $73,429
sleeve. $680.
Balance correction............................ 3 work-hours x $85 per hour = 0 255
$255.
----------------------------------------------------------------------------------------------------------------

For helicopters that accomplished a balance correction in
accordance with the instructions of the applicable AMM before the
effective date of this AD, except those that accomplished a balance
correction before the next flight after installing a new (zero total
hours time-in-service) sliding flange and a new (zero total hours time-
in-service) equipped splined sleeve, the corrective action that may be
needed could vary significantly from helicopter to helicopter. The FAA
has no data to determine the costs to accomplish the corrective action
or the number of helicopters that may require corrective action.

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.

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

0
1. The authority citation for part 39 continues to read as follows:

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

Sec. 39.13 [Amended]

0
2. The FAA amends Sec. 39.13 by:
0
a. Removing Airworthiness Directive 2023-25-14, Amendment 39-22641 (88
FR 89568, December 28, 2023); and
0
b. Adding the following new airworthiness directive:

Airbus Helicopters: Docket No. FAA-2026-4644; Project Identifier
MCAI-2024-00418-R.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive
(AD) by July 6, 2026.

(b) Affected ADs

This AD replaces AD 2023-25-14, Amendment 39-22641 (88 FR 89568,
December 28, 2023).

This AD applies to all Airbus Helicopters Model EC130T2
helicopters, certificated in any category, as identified in European
Union Aviation Safety Agency (EASA) AD 2024-0144, dated July 19,
2024 (EASA AD 2024-0144).

(d) Subject

Joint Aircraft System Component (JASC) Code 6510, Tail Rotor
Drive Shaft.

(e) Unsafe Condition

This AD was prompted by a report of a crack in the tailboom. The
FAA is issuing

[[Page 30260]]

this AD to address an excessive vibration level on the tail rotor
drive shaft. The unsafe condition, if not addressed, could result in
failure of the tail rotor drive shaft and loss of yaw control of the
helicopter.

(f) Compliance

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

(g) Required Actions

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, EASA AD 2024-0144.

(h) Exceptions to EASA AD 2024-0144

(1) Where EASA AD 2024-0144 requires compliance in terms of
flight hours, this AD requires using hours time-in-service.
(2) Where EASA AD 2024-0144 refers to its effective date, or
where EASA AD 2024-0144 refers to November 6, 2023 [the effective
date of EASA Emergency AD 2023-0190-E], this AD requires using the
effective date of this AD.
(3) Where EASA AD 2024-0144 refers to ``checks'', this AD
requires replacing that text with ``inspections''.
(4) Where paragraph (4) of EASA AD 2024-0144 specifies to
``contact AH [Airbus Helicopters] to obtain approved instructions,
and within the compliance time(s) specified therein, accomplish
those instructions accordingly'', this AD requires replacing that
text with ``accomplish corrective action in accordance with a method
approved by the Manager, International Validation Branch, FAA; or
EASA; or Airbus Helicopters' EASA Design Organization Approval
(DOA). If approved by the DOA, the approval must include the DOA-
authorized signature, and within the compliance time(s) specified
therein, accomplish those instructions accordingly.''
(5) This AD does not adopt the ``Remarks'' section of EASA AD
2024-0144.

(i) No Reporting Requirement

Although the material referenced in EASA AD 2024-0144 specifies
to submit certain information to the manufacturer, this AD does not
include that requirement.

(j) 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 local 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 (k) of
this AD and email to: <a href="/cdn-cgi/l/email-protection#30717d7f73705651511e575f46">[email&#160;protected]</a>.
(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.

(k) Additional Information

For more information about this AD, contact Eric Rivera,
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410,
Westbury, NY 11590; phone: (773) 412-9048; email:
<a href="/cdn-cgi/l/email-protection#5a3f2833397428332c3f283b6a6b1a3c3b3b743d352c">[email&#160;protected]</a>.

(l) Material Incorporated by Reference

(1) The Director of the Federal Register approved the
incorporation by reference of the material identified in this AD
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 2024-0144,
dated July 19, 2024.
(ii) [Reserved]
(3) For EASA material identified in this AD, contact EASA,
Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221
8999 000; email <a href="/cdn-cgi/l/email-protection#d19095a291b4b0a2b0ffb4a4a3bea1b0ffb4a4">[email&#160;protected]</a>; website easa.europa.eu. You may
find the EASA material on the EASA website ad.easa.europa.eu.
(4) You may view this material at 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 <a href="http://www.archives.gov/federal-register/cfr/ibr-locations">www.archives.gov/federal-register/cfr/ibr-locations</a> or email <a href="/cdn-cgi/l/email-protection#c5a3b7ebacabb6b5a0a6b1acaaab85aba4b7a4eba2aab3">[email&#160;protected]</a>.

Issued on May 19, 2026.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2026-10256 Filed 5-21-26; 8:45 am]
BILLING CODE 4910-13-P

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