DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0169; Directorate Identifier 2017-SW-003-AD;
Amendment 39-18818; AD 2017-02-51]
RIN 2120-AA64

Airworthiness Directives; Sikorsky Aircraft Corporation
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: We are publishing a new airworthiness directive (AD) for
Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters. This
AD requires inspecting certain bearings. This AD is prompted by reports
of failed bearings with subsequent loss of tail rotor (TR) control. The
actions of this AD are intended to address an unsafe condition on these
helicopters.

DATES: This AD becomes effective March 20, 2017 to all persons except
those persons to whom it was made immediately effective by Emergency AD
2017-02-51 issued on January 13, 2017, which contains the requirements
of this AD. We must receive comments on this AD by May 2, 2017.

ADDRESSES: You may send comments by any of the following methods:
Federal eRulemaking Docket: Go to http://www.regulations.gov. Follow the
online instructions for sending your comments electronically.
Fax: 202-493-2251.
Mail: Send comments to the U.S. Department of
Transportation, Docket Operations, M-30, West Building Ground Floor,
Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590-0001.
Hand Delivery: Deliver to the ``Mail'' address between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.
gov by searching for and locating Docket No. FAA-2017-
0169; or in person at the Docket Operations Office between 9 a.m. and 5
p.m., Monday through Friday, except Federal holidays. The AD docket
contains this AD, the economic evaluation, any comments received, and
other information. The street address for the Docket Operations Office
(telephone 800-647-5527) is in the ADDRESSES section. Comments will be
available in the AD docket shortly after receipt.
For service information identified in this final rule, contact
Sikorsky Aircraft Corporation, Customer Service Engineering, 124 Quarry
Road, Trumbull, CT 06611; telephone 1-800-Winged-S or 203-416-4299;
email: wcs_cust_service_eng.gr-sik@lmco.com. You may review the
referenced service information at the FAA, Office of the Regional
Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort
Worth, TX 76177.

FOR FURTHER INFORMATION CONTACT: Blaine Williams, Aerospace Engineer,
Boston Aircraft Certification Office, Engine & Propeller Directorate,
1200 District Avenue, Burlington, Massachusetts 01803; telephone (781)
238-7161; email blaine.williams@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

This AD is a final rule that involves requirements affecting flight
safety, and we did not provide you with notice and an opportunity to
provide your comments prior to it becoming effective. However, we
invite you to participate in this rulemaking by submitting written
comments, data, or views. We also invite comments relating to the
economic, environmental, energy, or federalism impacts that resulted
from adopting this AD. The most helpful comments reference a specific
portion of the AD, explain the reason for any recommended change, and
include supporting data. To ensure the docket does not contain
duplicate comments, commenters should send only one copy of written
comments, or if comments are filed electronically, commenters should
submit them only one time. We will file in the docket all comments that
we receive, as well as a report summarizing each substantive public
contact with FAA personnel concerning this rulemaking during the
comment period. We will consider all the comments we receive and may
conduct additional rulemaking based on those comments.

Discussion

On November 16, 2016, we issued Emergency AD 2016-24-51 to correct
an unsafe condition on Sikorsky Model S-92A helicopters with a TR pitch
change shaft (TRPCS) assembly, part number (P/N) 92358-06303-041 or P/N
92358-06303-042, with bearings that were manufactured prior to November
3, 2016. AD 2016-24-51 subsequently published in the Federal Register
as a final rule (81 FR 95425, December 28, 2016). AD 2016-24-51
requires removing from service TRPCS assemblies with less than 5 hours
time-in-service (TIS) since new or overhaul. For TRPCS assemblies with
between 5 and 80 hours TIS since new or overhaul, AD 2016-24-51 also
requires performing one-time inspections of the TRPCS bearings and
replacing the TRPCS assembly if the bearings do not pass these
inspections. AD 2016-24-51 was prompted by two reports of an operator
losing TR control caused by a failed TRPCS assembly.

Actions Since AD 2016-24-51 Was Issued

After AD 2016-24-51 was issued, we received a report of an S-92A
helicopter losing TR control because of a failed bearing with more than
80 hours TIS. We have now determined that the unsafe condition can
exist on TRPCS bearings regardless of hours TIS. Therefore, on January
13, 2017, we issued Emergency AD 2017-02-51, which applies to all TRPCS
assemblies, regardless of hours TIS. Emergency AD 2017-02-51 requires a
one-time visual inspection and a repetitive borescope inspection of the
TRPCS assembly bearing. The repetitive inspection is intended to detect
bearing deterioration. The actions in Emergency AD 2017-02-51 are
intended to detect a binding bearing, prevent loss of TR control, and
possible loss of control of the helicopter.

FAA's Determination

We are issuing this AD because we evaluated all the relevant
information and determined the unsafe condition described previously is likely to
exist or develop in other helicopters of the same type design.

Related Service Information

We reviewed Sikorsky Alert Service Bulletin 92-64-011, Basic Issue,
dated January 10, 2017 (ASB). The ASB describes procedures for
inspecting the TRPCS and bearing assemblies for ratcheting, binding,
and rough turning. The ASB also specifies periodic review of the health
and usage monitoring system (HUMS) tail gearbox bearing energy tool.

AD Requirements

This AD requires, before further flight, removing the TRPCS
assembly and inspecting the bearing. If the bearing does not rotate
freely; the bearing sounds rough or chatters; there is any purged
grease with metal particles; a nick or dent; or if there is a cut,
tear, or distortion in the bearing seal, before further flight,
replacing the TRPCS assembly is required. This AD also requires, within
10 hours TIS, and thereafter at intervals not to exceed 10 hours TIS,
inspecting the TRPCS assembly with a borescope. If the white Teflon
seal or snap ring is missing, or if there is a rip, tear, or heat
damage on the seal or if there is no gap in the snap ring, replacing
the TRPCS assembly is required before further flight.

Differences Between This AD and the Service Information

This AD requires repetitive borescope inspections of the TRPCS; the
ASB does not. The ASB specifies that operators review HUMS data in
addition to the one-time inspection and specifies contacting Sikorsky
if any discrepancies are found; this AD does not.

Costs of Compliance

We estimate that this AD will affect 80 helicopters of U.S.
Registry.
We estimate that operators may incur the following costs in order
to comply with this AD. At an average labor rate of $85 per hour,
borescope and visually inspecting the TRPCS assembly will require 16
work-hours, for a cost per helicopter of $1,360 and a cost of $108,800
for the U.S. fleet per inspection. If required, replacing a TRPCS
assembly will require 16 work-hours and required parts will cost
$4,000, for a cost per helicopter of $5,360.

FAA's Justification and Determination of the Effective Date

Providing an opportunity for public comments prior to adopting
these AD requirements would delay implementing the safety actions
needed to correct this known unsafe condition. Therefore, we found and
continue to find that the risk to the flying public justifies waiving
notice and comment prior to the adoption of this rule because the
previously described unsafe condition can result in loss of TR control
and certain actions must be accomplished before further flight and
within 10 hours TIS, a very short interval for these helicopters.
Since it was found that immediate corrective action was required,
notice and opportunity for prior public comments before issuing this AD
were impracticable and contrary to public interest and good cause
existed to make the AD effective immediately by Emergency AD 2017-02-
51, issued on January 13, 2017, to all known U.S. owners and operators
of these helicopters. These conditions still exist and the AD is hereby
published in the Federal Register as an amendment to section 39.13 of
the Federal Aviation Regulations (14 CFR 39.13) to make it effective to
all persons.

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.
We are 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

We determined that 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, I certify that this AD:
1. Is not a ``significant regulatory action'' under Executive Order
12866;
2. Is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979);
3. Will not affect intrastate aviation in Alaska to the extent that
it justifies making a regulatory distinction; and
4. 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.
We prepared an economic evaluation of the estimated costs to comply
with this AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by
Reference, Safety.

Adoption of 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 (AD):