DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0100; Project Identifier MCAI-2020-00309-E]
RIN 2120-AA64

Airworthiness Directives; Safran Helicopter Engines, S.A. (Type
Certificate Previously Held by Turbomeca, S.A.) Turboshaft Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for all Safran Helicopter Engines, S.A. Arriel 2C and Arriel 2S1 model
turboshaft engines. This proposed AD was prompted by reports of error
messages on the full authority digital engine control (FADEC) B digital
engine control unit (DECU), caused by blistering of the varnish on the
DECU circuit board. This proposed AD would require the replacement of
certain FADEC B DECUs. The FAA is proposing this AD to address the
unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by April 12,
2021.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:

Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the
instructions for submitting comments.

Fax: (202) 493-2251.

Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12 140, 1200 New
Jersey Avenue SE, Washington, DC 20590.

Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this NPRM, contact Safran
Helicopter Engines, S.A., Avenue du 1er Mai, 40220 Tarnos, France;
phone: +33 (0) 5 59 74 40 00. 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.

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0100; 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 NPRM, the
mandatory continuing airworthiness information (MCAI), any comments
received, and other information. The street address for Docket
Operations is listed above.

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: wego.wang@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include "Docket No. FAA-2021-0100; Project Identifier
MCAI-2020-00395-E" at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend
this proposal because of those comments.

Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
https://www.regulations.gov, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact received about this NPRM.

Confidential Business Information

CBI is commercial or financial information that is both customarily
and actually treated as private by its owner. Under the Freedom of
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public
disclosure. If your comments responsive to this NPRM contain commercial
or financial information that is customarily treated as private, that
you actually treat as private, and that is relevant or responsive to
this NPRM, it is important that you clearly designate the submitted
comments as CBI. Please mark each page of your submission containing
CBI as "PROPIN." The FAA will treat such marked submissions as
confidential under the FOIA, and they will not be placed in the public
docket of this NPRM. Submissions containing CBI should be sent to Wego
Wang, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue,
Burlington, MA 01803. Any commentary that the FAA receives which is not
specifically designated as CBI will be placed in the public docket for
this rulemaking.

Background

The European Union Aviation Safety Agency (EASA), which is the
Technical Agent for the Member States of the European Community, has
issued EASA AD 2020-0046, dated March 4, 2020 (referred to after this
as "the MCAI"), to address the unsafe condition on these products.
The MCAI states:

Occurrences have been reported of FADEC B DECU error messages,
which were found to be caused by blistering of the varnish on the
DECU circuit board. Subsequent investigation determined that the use
of a non-compliant primer is related to the blistering effect which,
in wet conditions, can cause malfunction of the stepper motor.

This condition, if not corrected, could lead to loss of
automatic control on both engines concurrently, possibly resulting
in reduced control of the helicopter.

To address this potentially unsafe condition, SAFRAN issued the
MSB, as defined in this [EASA] AD, to provide instructions for
identification and replacement of affected parts.

For the reason described above, this [EASA] AD requires
replacement of affected parts with serviceable parts. This [EASA] AD
also prohibits (re-)installation of affected parts.

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-2021-0100.

FAA's Determination

This product has been approved by EASA and is approved for
operation in the United States. Pursuant to our bilateral agreement
with the European Community, EASA has notified the FAA of the unsafe
condition described in the MCAI and service information. The FAA is
issuing this NPRM because the agency evaluated all the relevant
information provided by EASA and determined the unsafe condition
described previously is likely to exist or develop on other products of
the same type design.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Safran Helicopter Engines Note Technique AA187866,
Version A, dated October 18, 2019. This service information identifies
the serial numbers (S/Ns) of certain FADEC B DECUs installed on Arriel
2C and Arriel 2S1 model turboshaft engines. 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.

Other Related Service Information

The FAA reviewed Safran Helicopter Engines Mandatory Service
Bulletin (MSB) No. 292 73 2872, Version A, dated October 17, 2019. This
MSB describes procedures for identifying the S/Ns of certain FADEC B
DECUs and replacing certain FADEC B DECUs on Arriel 2C and Arriel 2S1
model turboshaft engines.

Proposed AD Requirements in This NPRM

This proposed AD would require the replacement of certain FADEC B
DECUs installed on Safran Helicopter Engines Arriel 2C and Arriel 2S1
model turboshaft engines.

Differences Between This Proposed AD and the MCAI or Service
Information

Safran Helicopter Engines MSB No. 292 73 2872 is applicable to
Arriel 2C, 2 C-PM, and Arriel 2S1 model turboshaft engines. This
proposed AD is only applicable to Arriel 2C and Arriel 2S1 model
turboshaft engines. There is no Arriel 2 C-PM model turboshaft engine
type certificated in the United States.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 148 engines installed on helicopters of U.S. registry.

The FAA estimates the following costs to comply with this proposed
AD:

Estimated Costs

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

The FAA determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 proposed
regulation:

(1) Is not a "significant regulatory action" under Executive
Order 12866,

(2) Would not affect intrastate aviation in Alaska, and

(3) Would 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 Proposed Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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: