AD 2016-23-10
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-76D | Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters |
Unsafe Condition
Autopilot unable to maintain level flight during certain flight conditions, specifically when at density altitudes greater than 13,000 feet, commanding a climb or descent rate greater than 1,000 fpm, and engaging ALT HOLD mode with large collective inputs.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Within 10 hours time-in-service (TIS), revise the Limitations section of the Rotorcraft Flight Manual (RFM) to prohibit the use of ALT mode during a rate of climb or descent greater than 1,000 fpm.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 10 hours time-in-service (TIS)
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Sikorsky Aircraft Corporation Model S-76D helicopters, certificated in any category.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
We are adopting a new airworthiness directive (AD) for Sikorsky Aircraft Corporation Model S-76D helicopters. This AD requires revising the rotorcraft flight manual (RFM) to prohibit Barometric Altitude Hold (ALT) mode beyond a certain rate of climb or descent. This AD is prompted by a report of the autopilot being unable to maintain level flight during certain flight conditions. The actions specified by this AD are intended to prevent a significant pilot workload increase, pilot disorientation, and subsequent loss of control of the helicopter.
Document Text
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[Federal Register Volume 81, Number 227 (Friday, November 25, 2016)]
[Rules and Regulations]
[Pages 85124-85126]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2016-27771]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2016-9281; Directorate Identifier 2016-SW-033-AD;
Amendment 39-18717; AD 2016-23-10]
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 adopting a new airworthiness directive (AD) for
Sikorsky Aircraft Corporation Model S-76D helicopters. This AD requires
revising the rotorcraft flight manual (RFM) to prohibit Barometric
Altitude Hold (ALT) mode beyond a certain rate of climb or descent.
This AD is prompted by a report of the autopilot being unable to
maintain level flight during certain flight conditions. The actions
specified by this AD are intended to prevent a significant pilot
workload increase, pilot disorientation, and subsequent loss of control
of the helicopter.
DATES: This AD becomes effective December 12, 2016.
The Director of the Federal Register approved the incorporation by
reference of a certain document listed in this AD as of December 12,
2016.
We must receive comments on this AD by January 24, 2017.
ADDRESSES: You may send comments by any of the following methods:
<bullet> Federal eRulemaking Docket: Go to <a href="http://www.regulations.gov">http://www.regulations.gov</a>. Follow the online instructions for sending your
comments electronically.
<bullet> Fax: 202-493-2251.
<bullet> 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.
<bullet> 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 <a href="http://www.regulations.gov">http://www.regulations.gov</a> by searching for and locating Docket No. FAA-2016-
9281; 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, 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: <a href="/cdn-cgi/l/email-protection#c4b3a7b79ba7b1b7b09bb7a1b6b2ada7a19ba1aaa3eaa3b6e9b7adaf84a8a9a7abeaa7aba9"><span class="__cf_email__" data-cfemail="7f081c0c201c0a0c0b200c1a0d09161c1a201a111851180d520c16143f13121c10511c1012">[email protected]</span></a>. 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 <a href="http://www.regulations.gov">http://www.regulations.gov</a> by searching for and locating Docket No. FAA-2016-
9281.
FOR FURTHER INFORMATION CONTACT: John Coffey, Flight Test Engineer,
Boston Aircraft Certification Office, Engine & Propeller Directorate,
FAA, 1200 District Avenue, Burlington, Massachusetts 01803; telephone
(781) 238-7173; email <a href="/cdn-cgi/l/email-protection#244e4b4c4a0a474b4242415d644245450a434b52"><span class="__cf_email__" data-cfemail="87ede8efe9a9e4e8e1e1e2fec7e1e6e6a9e0e8f1">[email protected]</span></a>.
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.
[[Page 85125]]
Discussion
We are adopting a new AD for Sikorsky Aircraft Corporation Model S-
76D helicopters. This AD requires revising the ``Automatic Flight
Control System'' section of the RFM Limitations by inserting a
limitation prohibiting the use of the ALT mode during a rate of climb
or descent greater than 1,000 feet/minute (fpm). This AD is prompted by
a report of the autopilot being unable to maintain level flight in
certain flight conditions. To explore the report further, the FAA
conducted additional flight tests, which revealed that when the
helicopter is at density altitudes greater than 13,000 feet and the
autopilot is commanding either a climb or descent at rates greater than
1,000 fpm, and the ALT HOLD mode is then engaged, the autopilot is
unable to maintain level flight when large collective inputs are
applied. These conditions saturate the stability augmentation system
(SAS) actuators, subsequently providing insufficient control response
during the collective input. As a result, the helicopter may experience
a dynamic response with roll excursions greater than 50 degrees of bank
angle and yaw excursions greater than 70 degrees of heading. This
condition could result in a significant increase in pilot workload,
pilot disorientation, and 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 this same type
design.
Related Service Information Under 1 CFR Part 51
Sikorsky issued S-76D RFM SA S76D-RFM-000, Temporary Revision No.
7, approved May 19, 2016, which revises the Limitations section by
prohibiting ALT mode during a rate of climb or descent greater than
1,000 fpm.
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.
AD Requirements
This AD requires, within 10 hours time-in-service (TIS), revising
the Limitations section of the RFM by inserting a limitation stating
that ALT mode shall not be engaged with a rate of climb or descent
greater than 1,000 fpm.
Interim Action
We consider this AD to be an interim action. The design approval
holder is planning to develop a modification that will address the
unsafe condition identified in this AD. Once this modification is
developed, approved, and available, we might consider additional
rulemaking.
Costs of Compliance
We estimate that this AD will affect 12 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 work-
hour, revising the RFM will require 0.5 work-hour, for cost of about
$43 per helicopter and $516 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 unsafe condition can
adversely affect control of the helicopter, and the required corrective
actions must be accomplished within 10 hours TIS.
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 contrary to
the public interest 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
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
0
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]
0
2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive (AD):
2016-23-10 Sikorsky Aircraft Corporation: Amendment 39-18717; Docket
No. FAA-2016-9281; Directorate Identifier 2016-SW-033-AD.
(a) Applicability
This AD applies to Model S-76D helicopters, certificated in any
category.
(b) Unsafe Condition
This AD defines the unsafe condition as an inability of the
autopilot to maintain level flight. This condition could result in a
significant increase in pilot workload, pilot disorientation, and
subsequent loss of control of the helicopter.
[[Page 85126]]
(c) Effective Date
This AD becomes effective December 12, 2016.
(d) Compliance
You are responsible for performing each action required by this
AD within the specified compliance time unless it has already been
accomplished prior to that time.
(e) Required Actions
Within 10 hours time-in-service, revise Section 1 Limitations,
``Automatic Flight Control System'' section, of the Rotorcraft
Flight Manual by one of the following methods:
(1) Insert Sikorsky S-76D SA S76D-RFM-000, Temporary Revision
No. 7, approved May 19, 2016; or
(2) Insert a copy of this AD; or
(3) Make pen-and-ink changes to add the information in Figure 1
to paragraph (e) of this AD.
[GRAPHIC] [TIFF OMITTED] TR25NO16.000
(f) Alternative Methods of Compliance (AMOCs)
(1) The Manager, Boston Aircraft Certification Office, FAA, may
approve AMOCs for this AD. Send your proposal to: John Coffey,
Flight Test Engineer, Boston Aircraft Certification Office, Engine &
Propeller Directorate, FAA, 1200 District Avenue, Burlington,
Massachusetts 01803; telephone (781) 238-7173; email
<a href="/cdn-cgi/l/email-protection#0c66636462226f636a6a69754c6a6d6d226b637a"><span class="__cf_email__" data-cfemail="92f8fdfafcbcf1fdf4f4f7ebd2f4f3f3bcf5fde4">[email protected]</span></a>.
(2) For operations conducted under a 14 CFR part 119 operating
certificate or under 14 CFR part 91, subpart K, we suggest that you
notify your principal inspector, or lacking a principal inspector,
the manager of the local flight standards district office or
certificate holding district office before operating any aircraft
complying with this AD through an AMOC.
(g) Subject
Joint Aircraft Service Component (JASC) Code: 2210, Autopilot
System.
(h) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference of the service information listed in this
paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this service information as applicable to do
the actions required by this AD, unless the AD specifies otherwise.
(i) Sikorsky S-76D SA S76D-RFM-000, Temporary Revision No. 7,
approved May 19, 2016.
(ii) Reserved.
(3) For Sikorsky service information identified in this AD,
contact Sikorsky Aircraft Corporation, Customer Service Engineering,
124 Quarry Road, Trumbull, CT 06611; telephone 1-800-Winged-S or
203-416-4299; email: <a href="/cdn-cgi/l/email-protection#354256466a564046416a465047435c56506a505b521b524718465c5e755958565a1b565a58"><span class="__cf_email__" data-cfemail="4e392d3d112d3b3d3a113d2b3c38272d2b112b202960293c633d27250e22232d21602d2123">[email protected]</span></a>.
(4) You may view this service information at 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.
(5) You may view this service information that is incorporated
by reference at the National Archives and Records Administration
(NARA). For information on the availability of this material at
NARA, call (202) 741-6030, or go to: <a href="http://www.archives.gov/federal-register/cfr/ibr-locations.html">http://www.archives.gov/federal-register/cfr/ibr-locations.html</a>.
Issued in Fort Worth, Texas, on November 4, 2016.
Lance T. Gant,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 2016-27771 Filed 11-23-16; 8:45 am]
BILLING CODE 4910-13-P
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Retrieved: Apr 4, 2026
Rights: U.S. Government Public Domain
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