DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0137; Project Identifier MCAI-2020-00269-E]
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).
SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2014-04-06, which applies to all Safran Helicopter Engines, S.A.
(Safran Helicopter Engines) Arrius 2B1, 2B1A, 2B2, and 2K1 model
turboshaft engines. AD 2014-04-06 requires initial and repetitive
inspections of the hydro-mechanical metering unit (HMU) high pressure
pump drive gear shaft splines, cleaning and inspections of the sleeve
assembly splines, and replacement of the sleeve assembly on the
affected high pressure pump drive gear shaft or replacement of the HMU
if the HMU fails inspection. Since the FAA issued AD 2014-04-06, the
manufacturer has published new service information that revises the
inspections for certain HMUs and reduces compliance times for initial
inspections. This proposed AD would require revised inspections and
continue to require cleaning of the sleeve assembly splines, and
replacement of the sleeve assembly on the affected high pressure pump
drive gear shaft or replacement of the HMU if the HMU fails an
inspection. 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 26, 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, 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.
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0137; 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: firstname.lastname@example.org.
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-2021-0137; Project Identifier
MCAI-2020-00269-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
the 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
The FAA issued AD 2014-04-06, Amendment 39-17764 (79 FR 9990,
February 24, 2014), (AD 2014-04-06), for all Turbomeca S.A. Arrius 2B1,
2B1A, 2B2, and 2K1 model turboshaft engines. AD 2014-04-06 was prompted
by in-flight shutdowns caused by interrupted fuel supply at the HMU. AD
2014-04-06 requires initial and repetitive inspections of the HMU high
pressure pump drive gear shaft splines, cleaning and inspections of the
sleeve assembly splines, and replacement of the sleeve assembly on the
affected high pressure pump drive gear shaft or replacement of the HMU
if the HMU fails inspection. The agency issued AD 2014-04-06 to prevent
in-flight shutdown and damage to the engine.
Actions Since AD 2014-04-06 Was Issued
Since the FAA issued AD 2014-04-06, the manufacturer has published
new service information that revises the inspections for certain HMUs,
reduces compliance times for initial inspections, and allows
application of non-cumulative tolerance of 10% of operating hours to be
applied to the timing of the repetitive inspection of HMUs installed on
The European Union Aviation Safety Agency (EASA), which is the
Technical Agent for the Member States of the European Community, has
issued EASA AD 2020-0033, dated February 25, 2020 (referred to after
this as "the MCAI"), to address the unsafe condition on these
products. The MCAI states:
A number of in-flight shutdown (IFSD) occurrences have been
reported for ARRIUS 2 engines. The results of the technical
investigations concluded that these events were caused by
deterioration of the splines on the high pressure (HP)/low pressure
(LP) pump assembly drive shaft of the HMU, which eventually
interrupted the fuel supply to the engine.
This condition, if not detected and corrected, could lead to
further cases of engine IFSD, possibly resulting in forced landing
with consequent damage to the helicopter and injury to occupants. To
address these occurrences, Turbomeca published MSB 319 73 2825 (up
to version G) to provide instructions for inspection of the HMU and
sleeve assembly. Consequently, EASA issued AD 2013-0082 to require
repetitive inspections of the drive gear shaft splines of the HP
pump, and, depending on findings, accomplishment of applicable
Since that [EASA] AD was issued, SAFRAN published the MSB to
provide specific inspection instructions for HMU installed on a
helicopter after 31 January 2013, to reduce the compliance time for
the initial inspection of Group 1 engines that were not previously
inspected in accordance with version G or later of the MSB, and to
provide some operational margin before the first inspection in all
For the reason described above, this [EASA] AD retains the
requirements of AD 2013-0082, which is superseded, and requires
accomplishment of the actions in accordance with the instructions of
the MSB, as defined in this [EASA] AD.
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-2021-0137.
This product has been approved by EASA and is approved for
operation in the United States. Pursuant to the FAA's bilateral
agreement with the European Community, EASA has notified the agency 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 in other products of
the same type design.
Related Service Information Under 1 CFR Part 51
The FAA reviewed Safran Helicopter Engines Mandatory Service
Bulletin (MSB) No. 319 73 2825, Version J, dated March 15, 2019. The
MSB describes procedures for inspecting the HMU high pressure pump
drive gear shaft splines and cleaning and inspecting the sleeve
assembly splines. 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.
Proposed AD Requirements in This NPRM
This proposed AD would retain certain requirements of AD 2014-04-
06. This proposed AD would require initial and repetitive inspections
of the HMU high pressure pump drive gear shaft splines. This proposed
AD would require cleaning of the sleeve assembly splines. This proposed
AD would also require replacing the HMU or the sleeve assembly on the
affected high pressure pump drive gear shaft if the HMU fails
Differences Between This Proposed AD and the Service Information or the MCAI
EASA AD 2020-0033 identifies applicable engines as Safran
Helicopter Engines Arrius 2B1, 2B1A, 2B2, 2G1, 2K1 and 2K2 model
turboshaft engines, all serial numbers. This AD does not include Safran
Helicopter Engines Arrius 2G1 and 2K2 model turboshaft engines in its
applicability since these engines are not type certificated in the
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 194 engines installed on helicopters of U.S. registry.
The FAA estimates the following costs to comply with this proposed AD:
COST ON U.S.
|Visual inspection of drive gear shaft splines; cleaning and inspection of sleeve assembly splines.
|| 2 work-hours x $85 per hour = $170.
The FAA estimates the following costs to do any necessary
replacements that would be required based on the results of the
proposed inspection. The agency has no way of determining the number of
aircraft that might need these replacements.
|Replace sleeve assembly on high-pressure pump drive gear shaft.
|| 1 work-hour x $85 per hour = $85
|| 1 work-hour x $85 per hour = $85
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.
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
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:
a. Removing Airworthiness Directive 2014-04-06, Amendment 39-17764 (79
FR 9990, February 24, 2014), and
b. Adding the following new airworthiness directive: