DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2020-0920; Project Identifier AD-2020-00662-R]
Airworthiness Directives; Sikorsky Aircraft and Sikorsky Aircraft
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: The FAA proposes to adopt a new airworthiness directive
for all Sikorsky Aircraft Model S-61L, S-61N, S-61NM, and S-61R
helicopters and Sikorsky Aircraft Corporation Model S-61A, S-61D, S-
61E, and S-61V restricted category helicopters. This proposed AD was
prompted by the manufacturer determining that there may be arm
assemblies in service that have accumulated 15,000 or more hours time-
in-service (TIS), which exceeds the service life limit for this
component. This proposed AD would require reviewing the mixer unit
component log card or equivalent record and, depending on the number of
hours TIS, calculating the remaining life of the arm assembly or
removing the arm assembly from service. 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 December
ADDRESSES: You may send comments, using the procedures found in
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow
instructions for submitting comments.
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 Sikorsky
Aircraft Corporation, 6900 Main Street, P.O. Box 9729, Stratford, CT
06615; phone: 203-386-4000. You may view this service information at
the FAA, Office of the Regional Counsel, Southwest Region, 10101
Hillwood Pkwy., Room 6N-321, Fort Worth, TX 76177. For information on
the availability of this material at the FAA, call 817-222-5110.
Examining the AD Docket
You may examine the AD docket on the internet at https://www.regulations.
gov by searching for and locating Docket No. FAA-2020-0920;
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, any comments received, and other information. The street
address for Docket Operations is listed above.
FOR FURTHER INFORMATION CONTACT: Neil Doh, Aerospace Engineer,
ACO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone:
781-238-7757; 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 the ADDRESSES section. Include "Docket No. FAA-2020-0920;
Project Identifier AD-2020-00662-R" 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 NPRM because of those comments.
Except for Confidential Business Information 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 proposal.
Confidential Business Information
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 Neil Doh, Aerospace Engineer, Boston ACO 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.
The FAA proposes to adopt a new AD for Sikorsky Aircraft Model S-
61L, S-61N, S-61NM, and S-61R helicopters and Sikorsky Aircraft
Corporation Model S-61A, S-61D, S-61E, and S-61V restricted category
helicopters, with an arm assembly, part number S6140-62614-009,
installed. The FAA learned from Sikorsky Aircraft Corporation that
Sikorsky S-61 Helicopter Alert Service Bulletin (ASB) 61B General-1,
Revision No. Z, dated November 13, 2018, which is applicable to
Sikorsky Model S-61L, S-61N, S-61NM, and S-61R helicopters, failed to
include the life limit of the redesigned arm assembly. As a result,
Sikorsky Aircraft Corporation determined that there may be arm
assemblies in service with 15,000 or more hours TIS, which exceeds the
service life limit for this component. The proposed actions are
intended to prevent an arm assembly from remaining in service beyond
its life limit. This condition, if not addressed, could result in
reduced or loss of tail rotor control and reduced control of the
The FAA is issuing this NPRM because the agency has determined that
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 Sikorsky S-61 Helicopter ASB 61B40-11, Basic
Issue, dated March 2, 2020 ("the ASB"). The ASB describes procedures
for a one-time inspection of the mixer unit component log card to
verify the arm assembly life limit and, if the life limit has been
exceeded, to replace the arm assembly for Sikorsky Model S-61L, S-61N,
and S-61NM helicopters. 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 the
Other Related Service Information
The FAA reviewed Sikorsky S-61 Helicopter ASB 61B General-1,
Revision AA, dated February 24, 2020. This service information
summarizes and lists parts with mandatory retirement times and
inspections for Sikorsky Model S-61L, S-61N, and S-61NM helicopters.
Proposed AD Requirements in This NPRM
This proposed AD would require reviewing the mixer unit component
log card or equivalent record and, depending on the hours time-in-
service of the arm assembly, calculating the remaining life of the arm
assembly or removing the arm assembly from service.
Differences Between This Proposed AD and the Service Information
The ASB is effective only for Sikorsky Aircraft Model S-61L, S-61N,
and S-61NM helicopters. In addition to these helicopters, the
applicability of this proposed AD also includes Sikorsky Aircraft Model
S-61R helicopters and Sikorsky Aircraft Corporation Model S-61A, S-61D,
S-61E, and S-61V restricted category helicopters. The FAA is proposing
to expand the applicability to prevent the installation of arm
assemblies that have exceeded their life limits on helicopters with a
similar type design as those helicopters affected by the ASB.
Costs of Compliance
The FAA estimates that this AD, as proposed, would affect 13
helicopters of U.S. registry.
The FAA estimates the following costs to comply with this proposed
||Cost per product
||Cost on U.S. operators
|Review mixer unit component log
or equivalent record.
||1 work-hour x $85 per hour =
The FAA estimates the following costs
to do any necessary log entry
or replacement that would be required based on the results of the
proposed mixer unit component log or equivalent record review. The FAA
has no way of determining the number of helicopters that might need
this log entry or replacement:
||Cost per product
|Add arm assembly entry and determine
||1 work-hour x $85 per hour =
|Replace arm assembly.
||9 work-hours x $85 per hour =
According to the manufacturer, some
of the costs of this proposed
AD may be covered under warranty, thereby reducing the cost impact on
affected individuals. The FAA does not control warranty coverage for
affected individuals. As a result, the FAA has included all costs in
the cost estimate.
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
(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
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