Rule2026-11560
Airworthiness Directives; Airbus Helicopters
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
June 9, 2026
Effective
July 14, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is superseding Airworthiness Directive (AD) 2025-06-04 for all Airbus Helicopters Model AS350B, AS350B1, AS350B2, AS350B3, AS350BA, AS350D, AS355E, AS355F, AS355F1, AS355F2, AS355N, AS355NP, EC130B4, and EC130T2 helicopters. AD 2025-06-04 required repetitively inspecting the main gearbox (MGB) bevel wheel and the MGB magnetic plug for particles and performing corrective actions if applicable and prohibited installing an affected MGB unless certain requirements were met. Since the FAA issued AD 2025-06-04, the FAA determined that AD 2025-06-04 contains errors in the interval compliance times. This AD continues to require the actions of AD 2025-06-04 and corrects the interval compliance times. The FAA is issuing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 91 Issue 110 (Tuesday, June 9, 2026)</title>
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[Federal Register Volume 91, Number 110 (Tuesday, June 9, 2026)]
[Rules and Regulations]
[Pages 34746-34750]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-11560]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-5032; Project Identifier AD-2025-01042-R;
Amendment 39-23373; AD 2026-12-03]
RIN 2120-AA64
Airworthiness Directives; Airbus Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2025-06-04
for all Airbus Helicopters Model AS350B, AS350B1, AS350B2, AS350B3,
AS350BA, AS350D, AS355E, AS355F, AS355F1, AS355F2, AS355N, AS355NP,
EC130B4, and EC130T2 helicopters. AD 2025-06-04 required repetitively
inspecting the main gearbox (MGB) bevel wheel and the MGB magnetic plug
[[Page 34747]]
for particles and performing corrective actions if applicable and
prohibited installing an affected MGB unless certain requirements were
met. Since the FAA issued AD 2025-06-04, the FAA determined that AD
2025-06-04 contains errors in the interval compliance times. This AD
continues to require the actions of AD 2025-06-04 and corrects the
interval compliance times. The FAA is issuing this AD to address the
unsafe condition on these products.
DATES: This AD is effective July 14, 2026.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of May 9, 2025
(90 FR 14723, April 4, 2025).
ADDRESSES:
AD Docket: You may examine the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2025-5032; 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 final rule, any comments received, the mandatory
continuing airworthiness information (MCAI), and other information. The
address for Docket Operations is U.S. Department of Transportation,
Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200
New Jersey Avenue SE, Washington, DC 20590.
Material Incorporated by Reference:
<bullet> For European Union Aviation Safety Agency (EASA) material
identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668
Cologne, Germany; phone: +49 221 8999 000; email: <a href="/cdn-cgi/l/email-protection#df9e9bac9fbabeacbef1baaaadb0afbef1baaa"><span class="__cf_email__" data-cfemail="6322271023060210024d0616110c13024d0616">[email protected]</span></a>;
website easa.europa.eu. You may find this material on the EASA website
at 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. It is also available at
<a href="http://regulations.gov">regulations.gov</a> under Docket No. FAA-2025-5032.
FOR FURTHER INFORMATION CONTACT: Luna Yang, Aviation Safety Engineer,
FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (847)
294-7380; email: <a href="/cdn-cgi/l/email-protection#d1bda4bfb0ffa8ffa8b0bfb691b7b0b0ffb6bea7"><span class="__cf_email__" data-cfemail="deb2abb0bff0a7f0a7bfb0b99eb8bfbff0b9b1a8">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Background
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 to supersede AD 2025-06-04, Amendment 39-22992 (90 FR
14723, April 4, 2025), (AD 2025-06-04). AD 2025-06-04 applied to all
Airbus Helicopters Model AS350B, AS350B1, AS350B2, AS350B3, AS350BA,
AS350D, AS355E, AS355F, AS355F1, AS355F2, AS355N, AS355NP, EC130B4, and
EC130T2 helicopters. The NPRM was published in the Federal Register on
November 25, 2025 (90 FR 53238). The NPRM was prompted by EASA AD 2023-
0044, dated February 28, 2023 (EASA AD 2023-0044) (also referred to as
the MCAI), issued by EASA, which is the Technical Agent for the Member
States of the European Union. The MCAI states that after a fleet design
review for detection of particles in the MGB, it was determined that
additional maintenance actions are necessary to improve detection of
particles in MGB that have certain part-numbered planet gear bearings
installed.
In the NPRM, the FAA proposed to continue to require the actions of
AD 2025-06-04 and revise the interval compliance times. The FAA is
issuing this AD to detect and correct particles in the MGB. The unsafe
condition, if not addressed, could result in reduced or loss of control
of the helicopter.
Discussion of Final Airworthiness Directive
Comments
The FAA received comments from two commenters. The commenters were
Airbus Helicopters and an anonymous individual. The individual did not
request any changes to the AD, therefore the FAA infers that the
commenter supported the NPRM. Airbus Helicopters requested that the FAA
require periodic inspections and requested revision to the interval
compliance times.'' The following presents the comments received on the
NPRM and the FAA's response to each comment.
Request for Borescope Bevel Wheel Inspection
Airbus Helicopters requested that the proposed AD be revised to
require a periodic borescope inspection of the bevel wheel without
condition. Airbus Helicopters stated that the proposed AD only requires
a borescope bevel wheel inspection in case of particles found on MGB
magnetic plugs during a visual inspection, and this does not address
the unsafe condition.
The FAA infers that Airbus Helicopters requested that the periodic
borescope bevel wheel inspections be required at defined compliance
times, without any conditions in accordance with the Airbus material.
The proposed AD already adopts paragraph (1) of EASA AD 2023-0044,
which requires accomplishing repetitive borescope inspections of the
bevel wheel of the affected MGB in accordance with the instructions of
the material. Therefore, there is no change made to this AD based on
this request.
Request for Correction of the Compliance Times
Airbus Helicopters stated the interval compliance times listed in
Table 1 to paragraph (h)(6)(i) of the proposed AD (150 hours time-in-
service (TIS) for EC130T2 and 100 hours TIS for all other versions) are
not in accordance with published maintenance documents, including the
Airworthiness Limitations Section, the Master Servicing Manual, the
Aircraft Maintenance Manual (AMM), or the Maintenance Manual.
The exception in paragraph (h)(6) of the proposed AD was intended
to address the compliance times of the AMM tasks and not change the
inspection requirement. After further review the FAA has determined
this exception, which includes Table 1 to paragraph (h)(6)(i), is no
longer necessary due to the FAA incorporating the MCAI compliance
times. Accordingly, the final rule has been updated with the deletion
of this exception and table.
Conclusion
The FAA reviewed the relevant data, considered any comments
received, and determined that air safety requires adopting the AD as
proposed. Accordingly, the FAA is issuing this AD to address the unsafe
condition on these products. Except for minor editorial changes, and
any other changes described previously, this AD is adopted as proposed
in the NPRM. None of the changes will increase the economic burden on
any operator.
Material Incorporated by Reference Under 1 CFR Part 51
This AD requires EASA AD 2023-0044, which the Director of the
Federal Register approved for incorporation by reference as of May 9,
2025 (90 FR 14723, April 4, 2025). EASA AD 2023-0044 specifies
procedures for performing repetitive borescope visual inspections of
the bevel wheel of the affected MGB for particles, collecting and
analyzing any particles detected, and depending on the results,
accomplishing further actions, accomplishing corrective action in
accordance with the ASB, or contacting AH [Airbus Helicopters] for
further corrective action. EASA AD 2023-0044 also specifies procedures
for accomplishing a borescope visual inspection of the bevel wheel of
the
[[Page 34748]]
affected MGB for particles following the detection of any particles at
the MGB magnetic plug during accomplishment of certain maintenance
tasks and depending on the results, taking corrective action. EASA AD
2023-0044 also prohibits installing an affected MGB on any helicopter
unless certain requirements are met.
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.
Differences Between This AD and the MCAI
The MCAI applies to Model AS350BB helicopters, whereas this AD does
not because that model does not have an FAA type certificate.
Where Note 1 in the material referenced in the MCAI specifies the
option of 1 mechanical technician and 1 crew member, for this AD, the
pilot is only permitted to turn the tail rotor (b) because the other
actions specified in the note must be accomplished by persons
authorized under 14 CFR 43.3. Therefore, for the purposes of this AD,
the owner/operator (pilot) may turn the tail rotor (b) and must enter
compliance with the applicable paragraph of this AD in the helicopter
maintenance records in accordance with 14 CFR 43.9(a) and
91.417(a)(2)(v). The pilot may perform this action because it only
involves turning the tail rotor (b). This action can be performed
equally well by a pilot or a mechanic. This action is an exception to
the FAA's standard maintenance regulations.
Where the material referenced in the MCAI specifies contacting
Airbus Helicopters for a certain action, this AD requires accomplishing
action in accordance with a method approved by the FAA, EASA, or Airbus
Helicopters' EASA Design Organization Approval.
Costs of Compliance
The FAA estimates that this AD affects 522 helicopters of U.S.
registry.
The FAA estimates the following costs to comply with this AD:
Estimated Costs
----------------------------------------------------------------------------------------------------------------
Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Visually inspect MGB bevel wheel...... 1 work-hour x $85 per $0 $85 $44,370
hour = $85.
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The new requirements of this AD add no additional economic burden.
The FAA estimates the following costs to do any on-condition
actions that would be required based on the results of the inspections.
The agency has no way of determining the number of helicopters that
might need these on-condition actions:
On-Condition Costs
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Action Labor cost Parts cost Cost per product
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Collect particles and perform 6 work-hours x $85 per $0..................... $510.
metallurgical analysis. hour = $510.
Close monitoring..................... 2 work-hours x $85 per $0..................... $170 per close
hour = $170. monitoring cycle.
Perform visual borescope inspection 1 work-hour x $85 per $0..................... $85.
of MGB bevel wheel. hour = $85.
Replace epicyclic module............. 56 work-hours x $85 per $50,524 (overhauled)... $55,284 per module.
hour = $4,760.
Replace bevel reduction module....... 56 work-hours x $85 per $18,500 (overhauled)... $23,260 per module.
hour = $4,760.
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Certain corrective action could vary significantly from helicopter
to helicopter. The FAA has no data to determine the costs to accomplish
the 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
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,
(2) Will not affect intrastate aviation in Alaska, and
(3) Will 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 Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
1. The authority citation for part 39 continues to read as follows:
[[Page 34749]]
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 2025-06-04, Amendment 39-22992 (90
FR 14723, April 4, 2025); and
0
b. Adding the following new airworthiness directive:
2026-12-03 Airbus Helicopters: Amendment 39-23373; Docket No. FAA-
2025-5032; Project Identifier AD-2025-01042-R.
(a) Effective Date
This airworthiness directive (AD) is effective July 14, 2026.
(b) Affected ADs
This AD replaces AD 2025-06-04, Amendment 39-22992 (90 FR 14723,
April 4, 2025) (AD 2025-06-04).
(c) Applicability
This AD applies to all Airbus Helicopters Model AS350B, AS350B1,
AS350B2, AS350B3, AS350BA, AS350D, AS355E, AS355F, AS355F1, AS355F2,
AS355N, AS355NP, EC130B4, and EC130T2 helicopters, certificated in
any category.
(d) Subject
Joint Aircraft System Component (JASC) Code 6320, Main rotor
gearbox.
(e) Unsafe Condition
This AD was prompted by an assessment performed by the
manufacturer which revealed that additional maintenance actions are
necessary to improve detection of particles in the main gearbox
(MGB) with certain part-numbered planet gear bearings installed. The
FAA is issuing this AD to detect and correct particles in the MGB.
The unsafe condition, if not addressed, could result in reduced or
loss of 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, European Union Aviation Safety Agency AD 2023-0044,
dated February 28, 2023 (EASA AD 2023-0044).
(h) Exceptions to EASA AD 2023-0044
(1) Where EASA AD 2023-0044 defines ``serviceable MGB'' as ``An
affected MGB which has accumulated less than 330 flight hours (FH)
since new (first installation on a helicopter), or since an
overhaul, or since an inspection in accordance with the instructions
of the ASB'', this AD requires replacing that text with ``An
affected MGB which has accumulated less than 330 total hours time-
in-service (TIS) since new (zero total hours TIS), since last
overhaul if an overhaul has been accomplished, or since last
inspection and any specified corrective action in accordance with
the instructions of the ASB if an inspection and any specified
corrective action by following the instructions of the ASB have been
accomplished''.
(2) Where EASA AD 2023-0044 requires compliance in terms of
flight hours, this AD requires using hours TIS.
(3) Where EASA AD 2023-0044 refers to its effective date, this
AD requires using May 9, 2025 (the effective date of AD 2025-06-04).
(4) Where Note 1 in the material referenced in paragraph (1) of
EASA AD 2023-0044 specifies the option of 1 mechanical technician
and 1 crew member, for this AD, the pilot is only permitted to turn
the tail rotor (b). The owner/operator (pilot) holding at least a
private pilot certificate may turn the tail rotor (b) and must enter
compliance with paragraph (g) of this AD in the helicopter
maintenance records in accordance with 14 CFR 43.9(a) and
91.417(a)(2)(v). The record must be maintained as required by 14 CFR
91.417, 121.380, or 135.43. All other actions specified in Note 1 in
the material referenced in paragraph (1) of EASA AD 2023-0044 must
be accomplished by persons authorized under 14 CFR 43.3.
(5) Where Note 2 in the material referenced in paragraph (1) of
EASA AD 2023-0044 specifies contacting Airbus Helicopters [AH] for
further instructions if the bottom of the radius (a6) of the bevel
wheel (a3) or head screws (a4) (see Figure 2) are not clearly
visible, this AD requires, before further flight, accomplishing
action in accordance with a method approved by the FAA, EASA, or
Airbus Helicopters' EASA Design Organization Approval (DOA). If
approved by the DOA, the approval must include the DOA-authorized
signature.
(6) Where the material referenced in paragraph (3) of EASA AD
2023-0044 specifies performing a metallurgical analysis and
contacting Airbus Helicopters if collected particles cannot be
characterized with Work Card 20-08-01-601, this AD does not require
contacting Airbus Helicopters but does require performing the
metallurgical analysis.
(7) Where the material referenced in paragraph (3) of EASA AD
2023-0044 contains a special flight permit provision, this AD does
not allow that provision but instead requires the special flight
permit limitations in paragraph (j) of this AD.
(8) Where the material referenced in paragraph (3) of EASA AD
2023-0044 specifies contacting Airbus Helicopters if the damaged
module cannot be identified, this AD requires, before further
flight, accomplishing action in accordance with a method approved by
the FAA, EASA, or Airbus Helicopters' EASA DOA. If approved by the
DOA, the approval must include the DOA-authorized signature.
(9) Where paragraph (5) of EASA AD 2023-0044 states ``to contact
AH for corrective action(s) instructions, and within the compliance
time specified therein, to accomplish those instructions
accordingly'', this AD requires replacing that text with
``accomplishing corrective actions in accordance with a method
approved by the FAA, EASA, or Airbus Helicopters' EASA DOA. If
approved by the DOA, the approval must include the DOA-authorized
signature''.
(10) Where paragraph (7) of EASA AD 2023-0044 states ``since new
(first installation on a helicopter), or since an overhaul, or since
an inspection in accordance with the instructions of the ASB, as
applicable, and, thereafter, as required by this AD'', this AD
requires replacing that text with ``since new (zero total hours
time-in-service), or since last overhaul if an overhaul has been
accomplished, or since last inspection and any specified corrective
action in accordance with the instructions of the ASB if an
inspection and any specified corrective action by following the
instructions of the ASB have been accomplished, and thereafter as
required by this AD''.
(11) This AD does not adopt the ``Remarks'' section of EASA AD
2023-0044.
(i) No Reporting Requirement
Although the material referenced in EASA AD 2023-0044 specifies
to submit certain information to the manufacturer, this AD does not
require that action.
(j) Special Flight Permit
A special flight permit may be issued in accordance with 14 CFR
21.197 and 21.199 to permit a one-time, non-revenue flight to a
location where the actions required by this AD can be accomplished.
This flight must be performed with only essential flight crew.
(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 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 (l) of
this AD and email to: <a href="/cdn-cgi/l/email-protection#b4f5f9fbf7f4d2d5d59ad3dbc2"><span class="__cf_email__" data-cfemail="ebaaa6a4a8ab8d8a8ac58c849d">[email protected]</span></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.
(l) Additional Information
For more information about this AD, contact Luna Yang, Aviation
Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY
11590; phone: (847) 294-7380; email: <a href="/cdn-cgi/l/email-protection#d7bba2b9b6f9aef9aeb6b9b097b1b6b6f9b0b8a1"><span class="__cf_email__" data-cfemail="95f9e0fbf4bbecbbecf4fbf2d5f3f4f4bbf2fae3">[email protected]</span></a>.
(m) 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 the AD specifies otherwise.
(3) The following material was approved for IBR on May 9, 2025
(90 FR 14723, April 4, 2025).
(i) European Union Aviation Safety Agency (EASA) AD 2023-0044,
dated February 28, 2023.
(ii) [Reserved]
[[Page 34750]]
(4) For EASA material identified in this AD, contact EASA,
Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999
000; email: <a href="/cdn-cgi/l/email-protection#0140457241646072602f6474736e71602f6474"><span class="__cf_email__" data-cfemail="bbfaffc8fbdedac8da95decec9d4cbda95dece">[email protected]</span></a>; website: easa.europa.eu. You may
find the EASA 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, 10101 Hillwood Parkway,
Fort Worth, TX 76177. For information on the availability of this
material at the FAA, call (817) 222-5110.
(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 <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#87e1f5a9eee9f4f7e2e4f3eee8e9c7e9e6f5e6a9e0e8f1"><span class="__cf_email__" data-cfemail="dcbaaef2b5b2afacb9bfa8b5b3b29cb2bdaebdf2bbb3aa">[email protected]</span></a>.
Issued on June 3, 2026.
Paul R. Bernado,
Acting Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2026-11560 Filed 6-8-26; 8:45 am]
BILLING CODE 4910-13-P
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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.