DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0874; Product Identifier 2015-SW-082-AD]
RIN 2120-AA64

Airworthiness Directives; Sikorsky Aircraft Corporation
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for
Sikorsky Aircraft Corporation (Sikorsky) Model S-76C helicopters. This
proposed AD would require inspecting the engine collective position
transducer (CPT). This proposed AD is prompted by reports of wear of
the CPT that has resulted in several One Engine Inoperative (OEI)
incidents. The proposed actions are intended to detect and prevent an
unsafe condition on these products.

DATES: We must receive comments on this proposed AD by November 13, 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-2017-0874;
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 proposed 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 proposed 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: Nick Rediess, Aviation Safety
Engineer, Boston ACO Branch, Compliance and Airworthiness Division,
1200 District Avenue, Burlington, MA 01803; telephone (781) 238-7159;
email nicholas.rediess@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

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 might
result from adopting the proposals in this document. The most helpful
comments reference a specific portion of the proposal, 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 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 proposed rulemaking. Before acting on this proposal, we
will consider all comments we receive on or before the closing date for
comments. We will consider comments filed after the comment period has
closed if it is possible to do so without incurring expense or delay.
We may change this proposal in light of the comments we receive.

Discussion

We propose to adopt a new AD for Sikorsky Model S-76C helicopters
with a Turbomeca, S.A., Arriel 2S1 or Arriel 2S2 engine and with a CPT
part number (P/N) 76900-01821-104 installed. This proposed AD is
prompted by 20 reports of One Engine Inoperative (OEI) incidents
resulting from wear of a CPT. One of these incidents resulted in a
rejected takeoff to an unprepared site. A CPT provides signals to the
Digital Engine Control Units (DECU) to anticipate power demand. A worn
CPT can send an erroneous signal to the DECU. This condition can cause
a power split between the two engines and a subsequent OEI condition,
which can result in an emergency landing.

Accordingly, this proposed AD would require initial and recurring
inspections of the CPTs, and depending on the outcome of the
inspections, replacing the CPT. The proposed actions are intended to
detect wear of a CPT prior to it causing an OEI condition and possible
emergency landing.

FAA's Determination

We are proposing this AD because we evaluated all known relevant
information and determined that an unsafe condition exists and is
likely to exist or develop on other products of the same type designs.

Related Service Information Under 1 CFR Part 51

We reviewed Sikorsky S-76 Helicopter Alert Service Bulletin (ASB)
76-73-8, Revision A, dated December 4, 2015 (ASB 76-73-8A), which
specifies a one-time inspection of total resistance, linearity
resistant movement, excitation voltage, and differential voltage of the
CPTs using CPT Text Box P/N 76700-40009-042.

We also reviewed Sikorsky Maintenance Manual, SA 4047-76C-2,
Temporary Revision No. 73-07, dated August 17, 2016 (TR 73-07), which
specifies procedures for removing, installing, and adjusting the CPTs,
and inspections of total resistance, linearity resistant movement,
excitation voltage, and differential voltage of the CPTs. TR 73-07 also
divides the procedures by CPT Test Box P/N by providing separate pro-
cedures for test boxes modified by Sikorsky Special Service Instructions
(SSI) No. 76-96, dated August 19, 2016, which is not incorporated by
reference in this proposed AD.

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 ADDRESSES section.

Other Related Service Information

We reviewed Sikorsky S-76 Helicopter ASB 76-73-8, Basic Issue,
dated August 21, 2015 (ASB 76-73-8). ASB 76-73-8 contains the same
procedures as ASB 76-73-8A; however, ASB 76-73-8A updates Sikorsky's
contact information for submitting a purchase order.

We also reviewed Sikorsky SA 4047-76C-2-1, Temporary Revision No.
5-181, dated August 21, 2015 (TR 5-181); Task 5-20-00 of Sikorsky
Airworthiness Limitations and Inspection Requirements, Publication No.
SA 4047-76C-2-1, Revision 24, dated December 15, 2015 (Task 5-20-00);
and Section 73-22-04 of Chapter 73 Engine Fuel and Control, of Sikorsky
Maintenance Manual, SA 4047-76C-2, Revision 31, dated December 15, 2015
(Section 73-22-04). TR 5-181 specifies adding CPT inspections
referenced in Section 73-22-04 to the 300-hour inspection checklist
contained in Task 5-20-00.

We reviewed Sikorksy Safety Advisory No. SSA-S76-11-0002, dated May
17, 2011. This service information provides precautionary instructions
to minimize hazardous situations that might result from an unreliable
CPT.

We reviewed Sikorsky SSI No. 76-96, dated August 19, 2016, which
specifies procedures to modify CPT Test Box P/N 76700-40009-042 and re-
identify it as P/N 76700-40009-043. This one-time modification reduces
the instructions to inspect the CPT and improves the inspection
accuracy.

We also reviewed Sikorsky SSI No. 76-87, dated July 24, 2015, and
SSI No. 76-87A, Revision A, dated August 21, 2015. These SSIs specify a
one-time inspection of total resistance, linearity resistant movement,
excitation voltage, and differential voltage of the CPTs using CPT Text
Box P/N 76700-40009-042.

Proposed AD Requirements

This proposed AD would require initial and recurring inspections of
each CPT by measuring resistance, linearity resistance movement, and
differential voltage, and depending on the outcome of the inspections,
replacing the CPT.

Differences Between This Proposed AD and the Service Information

Sikorsky ASB 76-73-8A and TR 73-07 specify using and returning
Sikorsky's CPT data sheet to Sikorsky. This proposed AD would not
require using Sikorsky's CPT data sheet or returning a data sheet to
Sikorsky. TR 73-07 specifies adjusting the CPT transducers. This
proposed AD would not require adjusting the CPT transducers. TR 73-07
specifies returning a failed CPT to Sikorsky. This proposed AD would
not require returning a failed CPT to Sikorsky.

Interim Action

We consider this proposed AD to be an interim action. The design
approval holder is currently developing a modification that will
address the unsafe condition identified in this proposed AD. Once this
modification is developed, approved, and available, we might consider
additional rulemaking.

Costs of Compliance

We estimate that this proposed AD would affect 90 helicopters of
U.S. Registry. We estimate that operators may incur the following costs
in order to comply with this AD. Labor costs are estimated at $85 per
work-hour. The inspections would take about 3.75 work-hours for an
estimated cost of $319 per helicopter and $28,710 for the U.S. fleet
per inspection cycle. Replacing a CPT would take about 6 work-hours and
parts would cost $3,072 for an estimated replacement cost of $3,582.

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 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, I certify this proposed regulation:

1. Is not a "significant regulatory action" under Executive Order
12866;

2. Is not a "significant rule" under the 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 proposed 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.

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 (AD):