DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2019-0389; Product Identifier 2018-SW-035-AD]
Airworthiness Directives; Sikorsky Aircraft Corporation
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: We propose to supersede Airworthiness Directive (AD) 2018-10-
07, which applies to Sikorsky Aircraft Corporation (Sikorsky) Model S-
76C helicopters. AD 2018-10-07 requires inspecting the engine
collective position transducer (CPT). Since we issued AD 2018-10-07, we
determined that an additional part-numbered engine CPT is affected by
the same unsafe condition. This proposed AD would retain the
requirements of AD 2018-10-07 and expand the applicability to include
the additional engine CPT. We are proposing this AD to address the
unsafe condition on these products.
DATES: We must receive comments on this proposed AD by July 8,
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 http://www.regulations.gov. Follow the
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 your local
Sikorsky Field Representative or Sikorsky's Service Engineering Group
at Sikorsky Aircraft Corporation, 124 Quarry Road, Trumbull, CT 06611;
telephone 1-800-Winged-S or 203-416-4299; email
firstname.lastname@example.org. Operators may also log on to the
Sikorsky 360 website at https://www.sikorsky360.com. 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 http://www.regulations.
gov by searching for and locating Docket No. FAA-2019-0389;
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 regulatory evaluation, any comments received, and other
information. The street address for Docket Operations (phone: 800-647-
5527) is listed above. Comments will be available in the AD docket
shortly after receipt.
FOR FURTHER INFORMATION CONTACT: Nick Rediess, Aerospace Engineer,
Boston ACO Branch, Compliance & Airworthiness Division, FAA, 1200
District Avenue, Burlington, MA 01803; phone: (781) 238-7159; email:
We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include "Docket No. FAA-2019-0389;
Product Identifier 2018-SW-035-AD" at the beginning of your comments.
We specifically invite comments on the overall regulatory, economic,
environmental, and energy aspects of this NPRM. We will consider all
comments received by the closing date and may amend this NPRM because
of those comments.
We will post all comments we receive, without change, to http://www.
regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.
We issued AD 2018-10-07, Amendment 39-19282 (83 FR 23355, May 21,
2018), ("AD 2018-10-07"), for Sikorsky Model S-76C helicopters with a
Turbomeca, S.A., Arriel 2S1 or Arriel 2S2 engine with an engine CPT
part number (P/N) 76900-01821-104 installed. AD 2018-10-07 requires
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. AD 2018-10-07
resulted from 20 reports of One Engine Inoperative (OEI) incidents
resulting from wear of an engine CPT. We issued AD 2018-10-07 to detect
wear of a CPT prior to it causing an OEI condition and possible
Actions Since AD 2018-10-07 Was Issued
Since AD 2018-10-07 was issued, Sikorsky has introduced CPT P/N
76900-01821-105. While this part is expected to be an improvement over
CPN P/N 76900-01821-104 in regard to the frequency of the potential
unsafe condition, there is not enough service history on this new part
to indicate that it will eliminate the unsafe condition.
This NPRM would retain the requirements of AD 2018-10-07 and would
expand the applicability to include engine CPT P/N 76900-01821-105.
Inspections of engine CPT P/N 76900-01821-105 are necessary since it is
subject to the same unsafe condition as P/N 76900-01821-104 due to
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 Test Box P/N 76700-40009-042.
We reviewed Sikorsky Maintenance Manual, SA 4047-76C-2, Temporary
Revision No. 73-07, dated August 17, 2016 (TR 73-07), which specifies
removing, installing, and adjusting the CPTs, and inspecting total
resistance, linearity resistant movement, excitation voltage, and differ-
ential voltage of the CPTs. TR 73-07 also divides the procedures by CPT
Test Box P/N by providing separate procedures for test boxes modified
Sikorsky Special Service Instructions (SSI) No. 76-96, dated August 19,
2016, which is not incorporated by reference in this AD.
We also reviewed Sikorsky Maintenance Manual, SA 4047-76C-2,
Temporary Revision No. 73-08, dated September 20, 2017 (TR 73-08),
which updates the procedures in TR 73-07. TR 73-08 does not divide the
procedures by CPT Test Box P/N as it eliminates the procedures for CPT
Test Box P/N 76700-40009-042. TR 73-08 omits obsolete figures and it
provides inspection results as pass or fail.
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
We also reviewed Sikorsky SSI No. 76-96, dated August 19, 2016,
which contains 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
We 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 Test
Box P/N 76700-40009-042.
We are proposing this AD because we evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the same type design.
Proposed AD Requirements
This proposed AD would retain all of the requirements of AD 2018-
10-07, but would add engine CPT P/N 76900-01821-105 to the
Differences Between This Proposed AD and the Service Information
Sikorsky ASB 76-73-8A, TR 73-07, and TR 73-08 specify using and
returning Sikorsky's CPT data sheet and any failed CPT to Sikorsky.
This proposed AD would not.
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
Costs of Compliance
We estimate that this proposed AD affects 115 helicopters of U.S.
registry. We estimate the following costs to comply with this proposed
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 $36,685 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
We have 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 that the proposed
(1) Is not a "significant regulatory action" under Executive
(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, 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.
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 removing Airworthiness Directive (AD)
2018-10-07, Amendment 39-19282 (83 FR 23355, May 21, 2018), and adding
the following new AD: