Rule2026-16047
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
August 6, 2026
Effective
September 10, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is adopting a new airworthiness directive (AD) for certain Airbus Helicopters Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, AS350D, EC130B4, and EC130T2 helicopters. This AD was prompted by reports of an incorrectly installed engine flange on the main gear box (MGB) engine coupling. This AD requires inspecting the MGB engine coupling for correct installation and, depending on the results, corrective actions. 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 150 (Thursday, August 6, 2026)</title>
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[Federal Register Volume 91, Number 150 (Thursday, August 6, 2026)]
[Rules and Regulations]
[Pages 50691-50693]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-16047]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2026-4638; Project Identifier MCAI-2023-00794-R;
Amendment 39-23431; AD 2026-16-01]
RIN 2120-AA64
Airworthiness Directives; Airbus Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain Airbus Helicopters Model AS350B, AS350BA, AS350B1, AS350B2,
AS350B3, AS350D, EC130B4, and EC130T2 helicopters. This AD was prompted
by reports of an incorrectly installed engine flange on the main gear
box (MGB) engine coupling. This AD requires inspecting the MGB engine
coupling for correct installation and, depending on the results,
corrective actions. The FAA is issuing this AD to address the unsafe
condition on these products.
DATES: This AD is effective September 10, 2026.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of September
10, 2026.
ADDRESSES:
AD Docket: You may examine the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2026-4638; 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, the mandatory continuing airworthiness
information (MCAI), any comments received, 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#9ddcd9eeddf8fceefcb3f8e8eff2edfcb3f8e8"><span class="__cf_email__" data-cfemail="c38287b083a6a2b0a2eda6b6b1acb3a2eda6b6">[email protected]</span></a>;
website: easa.europa.eu. You may find the EASA 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-2026-4638.
FOR FURTHER INFORMATION CONTACT: Aryanna Sanchez, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
phone: (520) 990-9321; email: <a href="/cdn-cgi/l/email-protection#ec8d9e958d82828dc298c29f8d828f848996ac8a8d8dc28b839a"><span class="__cf_email__" data-cfemail="4e2f3c372f20202f603a603d2f202d262b340e282f2f60292138">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Background
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to certain Airbus
Helicopters Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, AS350D,
EC130B4, and EC130T2 helicopters. The NPRM was published in the Federal
Register on May 15, 2026 (91 FR 27873). The NPRM was prompted by EASA
AD 2023-0127, dated June 27, 2023 (EASA AD 2023-0127) (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 on the final
assembly line, the engine flange on the MGB engine coupling may have
been installed inverted.
[[Page 50692]]
In the NPRM, the FAA proposed to require inspecting the MGB engine
coupling for correct installation and, depending on the results,
corrective actions.
The FAA is issuing this AD to detect and correct the inverted
installation of the engine flange on the MGB engine coupling. The
unsafe condition, if not detected and corrected, could result in the
loss of power transmission to the MGB and the main rotor and lead to
loss of 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-2026-4638.
Discussion of Final Airworthiness Directive
Comments
The FAA received a comment from one commenter, Papillon Airways
(Papillon). The following presents the comment received on the NPRM and
the FAA's response to the comment.
Request To Change the Applicability
Papillon requested the FAA revise the applicability of the NPRM, to
apply not only to the production date of the helicopters but also that
the NPRM apply to helicopters with less than 3,500 total flight hours.
Papillon stated the date ranges are too broad and they do not address
high usage aircraft. Papillon also stated that aircraft with more than
3,500 flight hours have likely already replaced the engine and
gearboxes [MGB] and would therefore no longer be affected by the unsafe
condition.
The FAA disagrees with revising the applicability of this final
rule. The FAA is unable to determine how many helicopters may have
replaced the MGBs or engines before 3,500 total hours time-in-service
(TIS) or how many helicopters may not have replaced the MGB or engine
before exceeding 3,500 total hours TIS. The FAA acknowledges that a
majority of the MGBs may have been replaced. Thus, adopting the MCAI
applicability ensures that all helicopters that may be affected are
included in this final rule. The FAA did not change this AD as a result
of this comment.
Conclusion
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 reviewed the relevant
data, considered any comments received, and determined that air safety
requires adopting this AD as proposed. Accordingly, the FAA is issuing
this AD to address the unsafe condition on these products. Except for
minor editorial changes, 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
The FAA reviewed EASA AD 2023-0127, which specifies procedures for
a one-time inspection of the MGB engine coupling for correct
installation. Depending on the results, EASA AD 2023-0127 specifies
installing a correctly assembled engine flange or a new engine flange.
EASA AD 2023-0127 also specifies reporting the inspection results to
the manufacturer. 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 Airbus Helicopters Model AS350BB helicopter,
whereas this AD does not because that model does not have an FAA type
certificate.
Costs of Compliance
The FAA estimates that this AD affects 4,102 helicopters of U.S.
registry.
The FAA estimates the following costs to comply with this AD:
Estimated Costs
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Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Inspect MGB engine coupling.............. 1 work-hour x $85 per hour $0 $85 $348,670
= $85.
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The FAA estimates the following costs to do any corrective actions
that would be required based on the results of the inspection. The
agency has no way of determining the number of helicopters that might
need this corrective action:
On-Condition Costs
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Action Labor cost Parts cost Cost per product
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Install engine flange........... 2 work-hours x $85 Up to $1,935................ Up to $2,105.
per hour = $170.
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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:
[[Page 50693]]
(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:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
0
2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive:
2026-16-01 Airbus Helicopters: Amendment 39-23431; Docket No. FAA-
2026-4638; Project Identifier MCAI-2023-00794-R.
(a) Effective Date
This airworthiness directive (AD) is effective September 10,
2026.
(b) Affected ADs
None.
(c) Applicability
This AD applies to all Airbus Helicopters, certificated in any
category, identified in paragraphs (c)(1) through (3) of this AD.
(1) Model AS350B, AS350BA, AS350B1, AS350B2, and AS350B3
helicopters, with a helicopter manufacture date before May 15, 2023.
(2) Model AS350D helicopters, with a helicopter manufacture date
before May 15, 2023, except helicopters equipped with a Lycoming
engine.
(3) Model EC130B4 and EC130T2 helicopters, with a helicopter
manufacture date before February 13, 2023.
Note 1 to paragraph (c)(1): Helicopters with AS350B3e
designation are Model AS350B3 helicopters.
(d) Subject
Joint Aircraft System Component (JASC) Code 6300, Main rotor
drive.
(e) Unsafe Condition
This AD was prompted by reports of an incorrectly installed
engine flange on the main gear box (MGB) engine coupling. The FAA is
issuing this AD to detect and correct the inverted installation of
the engine flange on the MGB engine coupling. The unsafe condition,
if not detected and corrected, could result in the loss of power
transmission to the MGB and the main rotor and lead to 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 2023-0127,
dated June 27, 2023 (EASA AD 2023-0127).
(h) Exceptions to EASA AD 2023-0127
(1) Where EASA AD 2023-0127 refers to its effective date, this
AD requires using the effective date of this AD.
(2) Where EASA AD 2023-0127 refers to flight hours, this AD
requires using hours time-in-service.
(3) Where the material referenced in EASA AD 2023-0127 specifies
discarding certain parts, this AD requires removing those parts from
service.
(4) This AD does not adopt the ``Remarks'' section of EASA AD
2023-0127.
(i) No Reporting Requirement
Although EASA AD 2023-0127 specifies to submit certain
information to the manufacturer, this AD does not require that
action.
(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 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 (k) of
this AD and email to <a href="/cdn-cgi/l/email-protection#9cddd1d3dfdcfafdfdb2fbf3ea"><span class="__cf_email__" data-cfemail="692824262a290f0808470e061f">[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.
(k) Additional Information
For more information about this AD, contact Aryanna Sanchez,
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410,
Westbury, NY 11590; phone: (520) 990-9321; email:
<a href="/cdn-cgi/l/email-protection#2f4e5d564e41414e015b015c4e414c474a556f494e4e01484059"><span class="__cf_email__" data-cfemail="8aebf8f3ebe4e4eba4fea4f9ebe4e9e2eff0caecebeba4ede5fc">[email protected]</span></a>.
(l) 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 2023-0127,
dated June 27, 2023.
(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: <a href="/cdn-cgi/l/email-protection#befffacdfedbdfcddf90dbcbccd1cedf90dbcb"><span class="__cf_email__" data-cfemail="87c6c3f4c7e2e6f4e6a9e2f2f5e8f7e6a9e2f2">[email protected]</span></a>; 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 <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#e38591cd8a8d90938680978a8c8da38d829182cd848c95"><span class="__cf_email__" data-cfemail="8fe9fda1e6e1fcffeaecfbe6e0e1cfe1eefdeea1e8e0f9">[email protected]</span></a>.
Issued on July 30, 2026.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2026-16047 Filed 8-5-26; 8:45 am]
BILLING CODE 4910-13-P
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