DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-0007; Project Identifier MCAI-2023-00998-R;
Amendment 39-23021; AD 2025-08-08]
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 all
Airbus Helicopters Model SA341G and SA342J helicopters. This AD was
prompted by reports of corrosion on the contact surfaces of the tail
rotor inclined and horizontal drive shaft flanges. This AD requires
repetitively inspecting the inclined and horizontal drive shaft flanges
and, depending on the results, replacing the inclined or horizontal
drive shaft. This AD also prohibits installing certain inclined and
horizontal drive shafts unless certain requirements are met. These
actions are specified in a European Union Aviation Safety Agency (EASA)
AD, which is proposed for incorporation by reference. The FAA is
issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective June 6, 2025.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of June 6,
2025.

ADDRESSES:
AD Docket: You may examine the AD docket at regulations.gov under
Docket No.FAA-2025-0007; 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:
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.
You may view this material at the FAA, Office of the
Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-
321, 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-2025-0007.

FOR FURTHER INFORMATION CONTACT: Evan Weaver, Aviation Safety Engineer,
FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316)
946-4152; email: Evan.P.Weaver@faa.gov.

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 all Airbus Helicopters
Model SA341G and SA342J (Gazelle) helicopters. The NPRM published in
the Federal Register on January 17, 2025 (90 FR 5748). The NPRM was
prompted by AD 2023-0168, dated August 31, 2023 (EASA AD 2023-0168)
(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
there have been several reports of corrosion on the contact surfaces of
the tail rotor inclined and horizontal drive shaft flanges. More
detailed non-destructive testing indicated pitting corrosion on the
mating faces of several flanges and further investigation revealed
various regions of intergranular failure beneath
the surface of corrosion pits. The unsafe condition, if not addressed,
could result in the failure of the tail rotor drive and subsequent loss
of control of the helicopter.
In the NPRM, the FAA proposed to require repetitively inspecting
the inclined and horizontal drive shaft flanges and, depending on the
results, replacing the inclined or horizontal drive shaft. In the NPRM,
the FAA also proposed to prohibit installing certain inclined and
horizontal drive shafts unless certain requirements are met. The FAA is
issuing this AD to address the unsafe condition on these products.
You may examine the MCAI in the AD docket at regulations.gov under
Docket No. FAA-2025-0007.

Discussion of Final Airworthiness Directive

Comments

The FAA received two comments from an anonymous commenter and an
individual who supported the NPRM without change.

Conclusion

These products have been approved by the 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, it has notified the FAA of the unsafe condition described in
the MCAI referenced above. The FAA reviewed the relevant data,
considered the comment 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, this AD is adopted as proposed in the NPRM.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed EASA AD 2023-0168, which specifies procedures for
repetitively inspecting the flanges of certain part-numbered inclined
and horizontal drive shafts for corrosion, and if corrosion is found,
replacing the affected inclined or horizontal drive shaft. EASA AD
2023-0168 also prohibits installing an affected inclined or horizontal
drive shaft on any helicopter unless it is a serviceable part as
defined within.
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 material referenced in the MCAI specifies sending corroded
parts to Airbus Helicopters, whereas this AD does not require that
action.

Costs of Compliance

The FAA estimates that this AD affects 63 helicopters of U.S.
registry. Labor rates are estimated at $85 per work-hour. Based on
these numbers, the FAA estimates the following costs to comply with
this AD.
Visually inspecting the inclined and horizontal drive shaft flanges
takes 4 work-hours for an estimated cost of $340 per helicopter and
$21,420 for the U.S. fleet, per inspection cycle. If required,
replacing the inclined or horizontal drive shaft takes 4 work-hours and
parts will cost $17,900 (inclined drive shaft) or $35,500 (horizontal
drive shaft), for an estimated cost of $18,240 or $35,840 respectively
per helicopter.

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

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]

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