DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2020-1118; Project Identifier MCAI-2020-00516-E;
Amendment 39-21451; AD 2021-05-08]
Airworthiness Directives; Safran Helicopter Engines, S.A. (Type
Certificate Previously Held by Turbomeca, S.A.) Turboshaft Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
SUMMARY: The FAA is adopting a new airworthiness directive (AD)
Safran Helicopter Engines, S.A. Arriel 2C, 2C1, 2S1, and 2S2 model
turboshaft engines. This AD was prompted by investigations by the
manufacturer following level 1 failures in flight (minor anomalies) and
level 2 failures on the ground (minor failures), where cracks were
found on the soldered joints of torque conformation boxes. This AD
requires performing initial and repetitive inspections of the
resistance values of the torque conformation box and, depending on the
results of the inspections, replacement of the torque conformation box.
The FAA is issuing this AD to address the unsafe condition on these
DATES: This AD is effective April 15, 2021.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of April 15,
ADDRESSES: For service information identified in this final rule,
contact Safran Helicopter Engines, S.A., Avenue du 1er Mai, Tarnos,
France; phone: +33 (0) 5 59 74 45 11. You may view this service
information at the FAA, Airworthiness Products Section, Operational
Safety Branch, 1200 District Avenue, Burlington, MA 01803. For
information on the availability of this material at the FAA, call (781)
238-7759. It is also available at https://www.regulations.gov by
searching for and locating Docket No. FAA-2020-1118.
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2020-1118; 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.
FOR FURTHER INFORMATION CONTACT: Wego Wang, Aviation Safety Engineer,
ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone:
(781) 238-7134; fax: (781) 238-7199; email: email@example.com.
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to all Safran Helicopter
Engines, S.A. Arriel 2C, 2C1, 2S1, and 2S2 model turboshaft engines.
The NPRM published in the Federal Register on
December 10, 2020 (85 FR 79438). The NPRM was prompted by
investigations by the manufacturer following level 1 failures in flight
(minor anomalies) and level 2 failures on the ground (minor failures),
where cracks were found on the soldered joints of torque conformation
boxes. In the NPRM, the FAA proposed to require performing initial and
repetitive inspections of the resistance values of the torque
conformation box and, depending on the results of the inspections,
replacement of the torque conformation box. The FAA is issuing this AD
to address the unsafe condition on these products.
The European Union Aviation Safety Agency (EASA), which is the
Technical Agent for the Member States of the European Community, has
issued EASA AD 2019-0110, dated May 21, 2019 (referred to after this as
``the MCAI''), to address the unsafe condition on these products. The
It was reported that, during investigations following level 1
failures in flight (minor anomalies) and level 2 failures on the
ground (minor failures), cracks were found on the soldered joints of
certain torque conformation boxes. Although no events in operation
were reported of One Engine Inoperative (OEI) ratings maximum power
unavailability, the failure mode analysis for these boxes
demonstrated that such event could not be excluded. This condition,
if not detected and corrected, could lead to engine in-flight shut-
down, possibly resulting in reduced control of the helicopter.
To address this potential unsafe condition, SAFRAN Helicopter
Engines issued the SB [Service Bulletin], to provide instructions
for repetitive checks of the box resistance values. For the reasons
described above, this [EASA] AD requires repetitive checks of the
affected part and, depending on findings, replacement of the
affected part with a serviceable part.
You may obtain further information by examining the MCAI in the AD
docket at https://www.regulations.gov by searching for and locating
Docket No. FAA-2020-1118.
Discussion of Final Airworthiness Directive Comments
The FAA received no comments on the NPRM or on the determination of
The FAA reviewed the relevant data 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. This AD is
adopted as proposed in the NPRM.
Related Service Information Under 1 CFR Part 51
The FAA reviewed Safran Helicopter Engines Mandatory Service
Bulletin (MSB) No. 292 72 2868, Version A, dated December 2018. This
service information specifies procedures for performing an inspection
of the resistance values of the torque conformation box. This service
information is reasonably available because the interested parties have
access to it through their normal course of business or by the means
identified in ADDRESSES.
Costs of Compliance
The FAA estimates that this AD affects 257 engines installed on
helicopters of U.S. registry.
The FAA estimates the following costs to comply with this AD:
||Cost per product
||Cost on U.S. operators
|Inspect resistance values of
the torque conformation box.
||1 work-hour x $85 per hour
The FAA estimates the following costs
to do any necessary
replacement that would be required based on the results of the
inspections. The agency has no way of determining the number of
aircraft that might need this replacement:
||Cost per product
|Replace the torque conformation
||1 work-hour x $85 per hour =
The FAA has included all known costs
in its cost estimate.
According to the manufacturer, however, some of the costs of this AD
may be covered under warranty, thereby reducing the cost impact on
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.
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 this AD:
(1) Is not a ``significant regulatory action'' under Executive
(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
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