DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2017-0946; Product Identifier 2017-SW-045-AD; Amendment
39-19081; AD 2017-22-01]
Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule; request for comments.
SUMMARY: We are adopting a new airworthiness directive (AD) for
Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters. This
AD requires adding operating limitations to a rotorcraft flight manual
(RFM). This AD is prompted by test results showing decoupling of the
flight director (FD) in certain flight conditions. The actions of this
AD are intended to address an unsafe condition on these products.
DATES: This AD becomes effective November 8, 2017.
The Director of the Federal Register approved the incorporation by
reference of a certain document listed in this AD as of November 8,
We must receive comments on this AD by December 26, 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.
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-
0946; or in person at the Docket Operations Office between 9 a.m. and
p.m., Monday through Friday, except Federal holidays. The AD docket
contains this AD, any incorporated by reference service information,
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 [email protected]. 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. It is also available on the Internet at http://www.
regulations.gov by searching for and locating Docket No. FAA-2017-
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 [email protected].
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.
We are adopting a new AD for Sikorsky Model S-92A helicopters with
a Flight Control Computer (FCC) part number 92900-01802-112 installed.
The FCC is part of the Search and Rescue (SAR) Automatic Flight Control
System (AFCS). During laboratory testing, Sikorsky discovered a defect
in the FCC software that results in the FD decoupling in all three axes
when pilot input is made to transition between two SAR AFCS modes. When
the AFCS is engaged in SAR Approach 2 (APP2) with an indicated airspeed
below VMINI (50 KIAS), the decoupling will occur if the
pilot initiates a transition to Velocity Hover Hold (VHLD) mode by
pressing the VHLD button on the Mode Select Panel (MSP). The decoupling
is annunciated to the pilot but only after a three-second delay. During
the delay, the rotorcraft may pitch up with the rate of descent
increases to as much as 450 fpm. Because of this, the pilot must take
immediate manual control of the rotorcraft after decoupling. This
condition could result in loss of control of the helicopter and flight
into terrain. According to Sikorsky, the root cause of the failure is
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 products of the same type design.
Related Service Information Under 1 CFR Part 51
Sikorsky has issued SA S92A-RFM-003 RFM Supplement (RFMS) No. 4
(Sikorsky SA S92A-RFM-003 RFMS No. 4), Revision 1, approved October 6,
2017, for the Model S-92A helicopter SAR AFCS. This revision of the
RFMS prohibits engaging VHLD during coupled SAR APP2 mode via MSP soft
key, adds a warning explaining the decoupling event and subsequent
aircraft behavior, and adds a note regarding correctly activating VHLD
mode with the cyclic trim release switch or selecting VHLD during Mark-
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
Sikorsky has issued letter CCS-92-APL-17-0001, dated July 31, 2017,
for Model S-92A helicopters, which describes the conditions that result
in the FD decoupling and provides instructions on how to avoid it. This
service information further provides instructions for re-engaging the
FD if decoupling occurs.
This AD requires revising the Operating Limitations section of
Sikorsky SA S92A-RFM-003 RFMS No. 4 by prohibiting engaging VHLD via
either MSP soft key during coupled SAR APP2 mode, adding a warning
describing the decoupling event and subsequent AFCS and aircraft
behavior, and adding a note regarding correctly activating VHLD mode
with the cyclic trim release switch or selecting VHLD during MOT.
We consider this AD to be an interim action. The design approval
holder is currently developing a modification that will address the
unsafe condition identified in this AD. Once this modification is
developed, approved, and available, we might consider additional
Costs of Compliance
We estimate that this AD will affect 87 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
Revising the RFMS will take about 0.5 work-hour for an estimated
cost of $43 per helicopter and $3,741 for the U.S. fleet.
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 find that
the risk to the flying public justifies waiving notice and comment
prior to the adoption of this rule because the required corrective
actions must be completed within 10 hours time-in-service.
Since an unsafe condition exists that requires the immediate
adoption of this AD, we determined that notice and opportunity for
public comment before issuing this AD are impracticable and that good
cause exists for making this amendment effective in less than 30 days.
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
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 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
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
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