Airworthiness Directives; Airbus Helicopters

[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 [www.gpo.gov]
[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 regulations.gov 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: [email protected]; 
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 
regulations.gov 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: [email protected].

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 regulations.gov 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
----------------------------------------------------------------------------------------------------------------
                                                                                       Cost per    Cost on U.S.
                  Action                            Labor cost           Parts cost    product       operators
----------------------------------------------------------------------------------------------------------------
Inspect MGB engine coupling..............  1 work-hour x $85 per hour            $0          $85        $348,670
                                            = $85.
----------------------------------------------------------------------------------------------------------------

    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
----------------------------------------------------------------------------------------------------------------
             Action                    Labor cost               Parts cost                 Cost per product
----------------------------------------------------------------------------------------------------------------
Install engine flange...........  2 work-hours x $85   Up to $1,935................  Up to $2,105.
                                   per hour = $170.
----------------------------------------------------------------------------------------------------------------

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 [email protected].
    (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: 
[email protected].

(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: [email protected]; 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 [email protected].

    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]
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