Special Conditions: Bell Helicopter Textron, Inc. (BHTI), Model 525 Helicopters; Flight Envelope Protection, 26226-26228 [2018-12077]
Download as PDF
<![CDATA[
26226
Federal Register / Vol. 83, No. 109 / Wednesday, June 6, 2018 / Proposed Rules
2013, the effective date of application to
the FAA.
If the Administrator finds that the
applicable airworthiness regulations
(i.e., 14 CFR part 29) do not contain
adequate or appropriate safety standards
for the BHTI Model 525 because of a
novel or unusual design feature, special
conditions are prescribed under the
provisions of § 21.16.
Special conditions are initially
applicable to the model for which they
are issued. Should the type certificate
for that model be amended later to
include any other model that
incorporates the same or similar novel
or unusual design feature, the special
conditions would also apply to the other
model under § 21.101.
In addition to the applicable
airworthiness regulations and special
conditions, the BHTI Model 525
helicopter must comply with the noise
certification requirements of 14 CFR
part 36, and the FAA must issue a
finding of regulatory adequacy under
section 611 of Public Law 92–574, the
‘‘Noise Control Act of 1972.’’
The FAA issues special conditions, as
defined in 14 CFR 11.19, in accordance
with § 11.38, and they become part of
the type-certification basis under
§ 21.17(a)(2).
daltland on DSKBBV9HB2PROD with PROPOSALS
Novel or Unusual Design Features
The BHTI Model 525 helicopter will
incorporate the following novel or
unusual design features: A four-axis full
authority digital FBW FCS. Pilot control
inputs, through the mechanically linked
cockpit controls (cyclic, collective,
directional pedals), are transmitted
electrically to each of the three Flight
Control Computers (FCCs). The pilot
control input signals are then processed
and transmitted to the hydraulic flight
control actuators which affect control of
the main and tail rotors.
Discussion
The proposed special condition will
require the minimum safety standard to
ensure awareness of proximity to
control limits at the main rotor and tail
rotor is provided to pilots of the Bell
Model 525 helicopter. The system
design must provide the pilot with
sufficient awareness of proximity to
control limits, traditionally achieved
through conventional flight controls by
the pilot’s inherent awareness of cyclic
stick and pedal position relative to
control stops.
Applicability
As discussed above, these special
conditions are applicable to the BHTI
Model 525 helicopter. Should BHTI
apply at a later date for a change to the
VerDate Sep<11>2014
16:21 Jun 05, 2018
Jkt 244001
type certificate to include another
model incorporating the same novel or
unusual design feature, the special
conditions would apply to that model as
well.
Conclusion
This action affects only certain novel
or unusual design features on one model
of rotorcraft. It is not a rule of general
applicability.
List of Subjects in 14 CFR Part 29
Aircraft, Aviation safety, Reporting
and recordkeeping requirements.
The authority citation for these
special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701,
44702, 44704.
The Proposed Special Conditions
Accordingly, the Federal Aviation
Administration (FAA) proposes the
following special conditions as part of
the type certification basis for Bell
Helicopter Textron, Inc., Model 525
helicopters:
Control Margin Awareness
In addition to the existing § 29.143
requirements, the following special
condition applies: The system design
must ensure that the flight crew is made
suitably aware whenever the means of
primary flight control approaches the
limits of control authority. For the
context of this special condition, the
term ‘‘suitable’’ indicates an appropriate
balance between nuisance and
necessary operation.
Issued in Ft. Worth, Texas, on May 24,
2018.
Jorge Castillo,
Acting Manager, Rotorcraft Standards
Branch, Policy and Innovation Division,
Aircraft Certification Service.
[FR Doc. 2018–12076 Filed 6–5–18; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 29
[Docket No.FAA–2017–1127; Notice No. 29–
044–SC]
Special Conditions: Bell Helicopter
Textron, Inc. (BHTI), Model 525
Helicopters; Flight Envelope
Protection
Federal Aviation
Administration (FAA), DOT.
ACTION: Notice of proposed special
conditions.
AGENCY:
PO 00000
Frm 00002
Fmt 4702
Sfmt 4702
This action proposes special
conditions for the BHTI Model 525
helicopter. This helicopter will have a
novel or unusual design feature
associated with fly-by-wire flight
control system (FBW FCS) flight
envelope protection. The applicable
airworthiness regulations do not contain
adequate or appropriate safety standards
for this design feature. These proposed
special conditions contain the
additional safety standards that the
Administrator considers necessary to
establish a level of safety equivalent to
that established by the existing
airworthiness standards.
DATES: Send your comments on or
before July 23, 2018.
ADDRESSES: Send comments identified
by docket number [FAA–2017–1127]
using any of the following methods:
• Federal eRegulations Portal: Go to
https://www.regulations.gov and follow
the online instructions for sending your
comments electronically.
• Mail: Send comments to Docket
Operations, M–30, U.S. Department of
Transportation (DOT), 1200 New Jersey
Avenue SE., Room W12–140, West
Building Ground Floor, Washington, DC
20590–0001.
• Hand Delivery of Courier: Take
comments to Docket Operations in
Room W12–140 of the West Building
Ground Floor at 1200 New Jersey
Avenue SE, Washington, DC, between 8
a.m., and 5 p.m., Monday through
Friday, except Federal holidays.
• Fax: Fax comments to Docket
Operations at 202–493–2251.
Privacy: The FAA will post all
comments it receives, without change,
to https://www.regulations.gov, including
any personal information the
commenter provides. Using the search
function of the docket website, anyone
can find and read the electronic form of
all comments received into any FAA
docket, including the name of the
individual sending the comment (or
signing the comment for an association,
business, labor union, etc.). DOT’s
complete Privacy Act Statement can be
found in the Federal Register published
on April 11, 2000 (65 FR 19477–19478),
as well as at https://DocketsInfo.dot.gov.
Docket: Background documents or
comments received may be read at
https://www.regulations.gov at any time.
Follow the online instructions for
accessing the docket or go to the Docket
Operations in Room W12–140 of the
West Building Ground Floor at 1200
New Jersey Avenue SE, Washington,
DC, between 9 a.m., and 5 p.m., Monday
through Friday, except Federal holidays.
FOR FURTHER INFORMATION CONTACT:
George Harrum, Aerospace Engineer,
SUMMARY:
E:\FR\FM\06JNP1.SGM
06JNP1
Federal Register / Vol. 83, No. 109 / Wednesday, June 6, 2018 / Proposed Rules
FAA, Rotorcraft Standards Branch,
Policy and Innovation Division, 10101
Hillwood Pkwy, Fort Worth, TX 76177;
telephone (817) 222–4087; email
George.Harrum@faa.gov.
SUPPLEMENTARY INFORMATION:
daltland on DSKBBV9HB2PROD with PROPOSALS
Comments Invited
We invite interested people to take
part in this rulemaking by sending
written comments, data, or views. The
most helpful comments reference a
specific portion of the special
conditions, explain the reason for any
recommended change, and include
supporting data.
We will consider all comments we
receive on or before the closing date for
comments. We will consider comments
filed late if it is possible to do so
without incurring expense or delay. We
may change these special conditions
based on the comments we receive.
Background
On December 15, 2011, BHTI applied
for a type certificate for a new transport
category helicopter designated as the
Model 525. The Model 525 is a medium
twin-engine rotorcraft. The design
maximum takeoff weight is 20,500
pounds, with a maximum capacity of 19
passengers and a crew of 2.
The BHTI Model 525 helicopter will
be equipped with a four axis full
authority digital FBW FCS that provides
for aircraft control through pilot input
and coupled flight director modes. The
FBW FCS will contain an advanced
flight control system that will alter the
nominal flight control laws to ensure
that the aircraft remains in a
predetermined flight envelope. These
Flight Envelope Protection (FEP)
features prevent the pilot or autopilot
functions from making control
commands that would force the aircraft
to exceed its structural, aerodynamic, or
operating limits. The design and
construction standards, specifically 14
CFR 29.779(a), require that movement of
the flight controls results in a
corresponding sense of aircraft motion
in the same axis. The airworthiness
standards for an automatic pilot system
in § 29.1329 covers design requirements
for basic operation of the system but
does not address dynamic flight
envelope limitations imposed by the
automatic pilot system. Currently there
are no specific airworthiness
requirements that address FBW FCS
FEP in rotorcraft. The proposed special
conditions will require the minimum
safety standard for the FEP features.
Type Certification Basis
Under the provisions of 14 CFR 21.17,
BHTI must show that the Model 525
VerDate Sep<11>2014
16:21 Jun 05, 2018
Jkt 244001
helicopter meets the applicable
provisions of part 29, as amended by
Amendment 29–1 through 29–55
thereto. The BHTI Model 525
certification basis date is December 31,
2013, the effective date of application to
the FAA.
If the Administrator finds that the
applicable airworthiness regulations
(i.e., 14 CFR part 29) do not contain
adequate or appropriate safety standards
for the BHTI Model 525 because of a
novel or unusual design feature, special
conditions are prescribed under the
provisions of § 21.16.
Special conditions are initially
applicable to the model for which they
are issued. Should the type certificate
for that model be amended later to
include any other model that
incorporates the same or similar novel
or unusual design feature, the special
conditions would also apply to the other
model under § 21.101.
In addition to the applicable
airworthiness regulations and special
conditions, the BHTI Model 525
helicopter must comply with the noise
certification requirements of 14 CFR
part 36, and the FAA must issue a
finding of regulatory adequacy under
section 611 of Public Law 92–574, the
‘‘Noise Control Act of 1972.’’
The FAA issues special conditions, as
defined in 14 CFR 11.19, in accordance
with § 11.38, and they become part of
the type-certification basis under
§ 21.17(a)(2).
Novel or Unusual Design Features
The BHTI Model 525 helicopter will
incorporate the following novel or
unusual design features: FBW FCS
incorporating FEP features. FEP is used
to prevent the pilot or an autopilot from
making control commands that would
force the rotorcraft to exceed its
structural, aerodynamic, or operating
limits. To accomplish this envelope
limiting, the FCS control laws change as
the limit is approached or exceeded.
Discussion
The proposed special conditions will
require the minimum safety standard for
the flight envelope protection features.
The FEP features must meet
requirements for handling qualities,
compatibility of flight parameter limit
values, response to dynamic
maneuvering, and failure modes.
Applicability
As discussed above, these special
conditions are applicable to the BHTI
Model 525 helicopter. Should BHTI
apply at a later date for a change to the
type certificate to include another
model incorporating the same novel or
PO 00000
Frm 00003
Fmt 4702
Sfmt 4702
26227
unusual design feature, the special
conditions would apply to that model as
well.
Conclusion
This action affects only certain novel
or unusual design features on one model
of rotorcraft. It is not a rule of general
applicability.
List of Subjects in 14 CFR Part 29
Aircraft, Aviation safety, Reporting
and recordkeeping requirements.
The authority citation for these
special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701,
44702, 44704.
The Proposed Special Conditions
Accordingly, the Federal Aviation
Administration (FAA) proposes the
following special conditions as part of
the type certification basis for Bell
Helicopter Textron, Inc., Model 525
helicopters:
Flight Envelope Protection
The Flight Envelope Protection (FEP)
features of the FCS must meet the
following requirements:
a. Onset characteristics of each
envelope protection feature must be
smooth, appropriate to the phase of
flight and type of maneuver, and not in
conflict with the ability of the pilot to
satisfactorily change rotorcraft flight
path, speed, or attitude within the
approved flight envelope.
b. Limit values of protected flight
parameters (and if applicable, associated
warning thresholds) must be compatible
with:
1. Rotorcraft structural limits;
2. Safe and controllable maneuvering
of the rotorcraft;
3. Margins to critical conditions.
Dynamic maneuvering, airframe and
system tolerances (both manufacturing
and in-service), and non-steady
atmospheric conditions—in any
appropriate combination and phase of
flight—must not result in a limited
flight parameter beyond the nominal
design limit value that would cause
unsafe flight characteristics;
4. Rotor rotational speed limits;
5. Blade stall limits; and
6. Engine and transmission torque
limits.
c. The aircraft must be responsive to
pilot-commanded dynamic
maneuvering within a suitable range of
the parameter limits that define the
approved flight envelope.
d. The FEP system must not create
unusual or adverse flight characteristics
when atmospheric conditions or
unintentional pilot action causes the
E:\FR\FM\06JNP1.SGM
06JNP1
26228
Federal Register / Vol. 83, No. 109 / Wednesday, June 6, 2018 / Proposed Rules
approved flight envelope to be
exceeded.
e. When simultaneous envelope
limiting is active, adverse coupling or
adverse priority must not result.
f. Following a single FEP failure
shown to not be extremely improbable,
the rotorcraft must:
1. Be capable of continued safe flight
and landing;
2. Be capable of initial counteraction
of malfunctions without requiring
exceptional pilot skill or strength;
3. Be controllable and maneuverable
when operated with a degraded FCS,
within a practical flight envelope
identified in the Rotorcraft Flight
Manual;
4. Be capable of prolonged instrument
flight without requiring exceptional
pilot skill;
5. Meet the controllability and
maneuverability requirements of 14 CFR
part 29 Subpart B throughout a practical
flight envelope; and
6. Be safely controllable following any
additional failure or malfunction shown
to not be extremely improbable
occurring within the approved flight
envelope.
Issued in Fort Worth, Texas, on May 24,
2018.
Jorge Castillo,
Acting Manager, Rotorcraft Standards
Branch, Policy and Innovation Division,
Aircraft Certification Services.
[FR Doc. 2018–12077 Filed 6–5–18; 8:45 am]
BILLING CODE 4910–13–P
CONSUMER PRODUCT SAFETY
COMMISSION
16 CFR Chapter II
[Docket No. CPSC–2018–0014]
Resubmission of Petition To Mandate
a Uniform Labeling Method for
Traction of Floor Coverings, Floor
Coverings With Coatings, and Treated
Floor Coverings; Request for
Comments
Consumer Product Safety
Commission.
ACTION: Notification of petition for
rulemaking.
AGENCY:
The U.S. Consumer Product
Safety Commission (CPSC) received a
resubmitted petition from the National
Floor Safety Institute (petitioner or
NFSI), requesting that the agency
require manufacturers of floor coverings
and coatings to label their products and
provide point of purchase information
regarding slip-resistance, using the
American National Standards Institute
daltland on DSKBBV9HB2PROD with PROPOSALS
SUMMARY:
VerDate Sep<11>2014
16:21 Jun 05, 2018
Jkt 244001
(ANSI) B101.5–2014 Standard Guide for
Uniform Labeling Method for Identifying
the Dynamic Coefficient of Friction
(Traction) of Floor Coverings, Floor
Coverings with Coatings, and Treated
Floor Coverings (ANSI B101.5). The
Commission invites written comments
concerning this petition.
DATES: Submit comments by August 6,
2018.
ADDRESSES: Submit comments,
identified by Docket No. CPSC–2018–
0014, by any of the following methods:
Electronic Submissions: Submit
electronic comments to the Federal
eRulemaking Portal at: https://
www.regulations.gov. Follow the
instructions for submitting comments.
The Commission does not accept
comments submitted by electronic mail
(email), except through
www.regulations.gov. The Commission
encourages you to submit electronic
comments by using the Federal
eRulemaking Portal, as described above.
Written Submissions: Submit written
comments by mail/hand delivery/
courier to: Office of the Secretariat,
Consumer Product Safety Commission,
Room 820, 4330 East West Highway,
Bethesda, MD 20814; telephone (301)
504–7923.
Instructions: All submissions received
must include the agency name and
docket number for this notice. All
comments received may be posted
without change to https://
www.regulations.gov, including any
personal identifiers, contact
information, or other personal
information provided. Do not submit
confidential business information, trade
secret information, or other sensitive or
protected information that you do not
want to be available to the public. If
furnished at all, such information
should be submitted by mail/hand
delivery/courier.
Docket: For access to the docket to
read background documents or
comments received, go to: https://www.
regulations.gov, insert docket number
CPSC–2018–0014 into the ‘‘Search’’ box,
and follow the prompts.
FOR FURTHER INFORMATION CONTACT:
Rocky Hammond, Office of the
Secretary, Consumer Product Safety
Commission, 4330 East West Highway,
Bethesda, MD 20814; telephone: 301–
504–6833; email: RHammond@cpsc.gov.
SUPPLEMENTARY INFORMATION: On April
19, 2018, NFSI submitted a petition,
docketed as CP 18–2, requesting that the
Commission require manufacturers of
floor coverings and coatings to label
their products, and provide point-ofpurchase information regarding slipresistance, using the ANSI B101.5
PO 00000
Frm 00004
Fmt 4702
Sfmt 4702
voluntary standard. NFSI’s petition
request is a resubmission of a prior
petition (CP 16–1), which the
Commission voted to deny.1 The
resubmitted petition contains certain
modifications and additional
information.
As with the previous petition, NFSI
states that it seeks to reduce injuries and
fatalities related to consumer slips and
falls, particularly involving the elderly,
by requesting CPSC to mandate that
floor coverings for sale to consumers be
labeled to provide information about the
traction of each product. NFSI states
that different types of floor coverings
have wide ranging differences in slipresistance, which can make certain
types of flooring inappropropriate for a
specific use. NFSI contends that
currently, consumers have no uniform
information to compare differences in
traction with various floor covering
options. NFSI states that the labeling it
urges is easy to understand and will
benefit consumers, particularly the
elderly, by informing consumers of the
traction or safety of the products at the
point of sale.
Responding to commenters’ and the
Commission’s concerns regarding the
previous petition (CP 16–1), NFSI made
modifications to the current petition
request and provided additional
information to support its petition for
rulemaking. By this notice, the
Commission seeks comments
concerning this renewed petition,
including whether the modifications
and additional information provided by
NFSI address the concerns set forth in
the Commission’s January 19, 2017
letter to NFSI denying petition CP 16–
1.2 In particular, the Commission seeks
comment on the petitioner’s proposed
method for determining wet dynamic
coefficient of friction, and whether such
method is accurate and repeatable on all
hard surfaces that would be subject to
the proposed labeling.
The petition is available at: https://
www.regulations.gov, under Docket No.
CPSC–2018–0014, Supporting and
Related Materials. Alternatively,
interested parties may obtain a copy of
the petition by writing or calling the
1 December 13, 2016 Record of Commission
Action, available at: https://www.cpsc.gov/s3fspublic/RCA%20-%20Petition%20CP%20161%20Labeling%20Requirements%20Regarding
%20Slip-Resistance%20of%20Floor%20Coverings
%20121316.pdf.
2 January 18, 2017 Record of Commission Action
and January 19, 2017 Letter to Russell J. Kendzior,
President and Chairman of the Board, National
Floor Safety Institute, available at: https://
www.cpsc.gov/s3fs-public/RCA%20-%20Draft%20
Letter%20to%20Petitioner%20Regarding%20
Denial%20of%20Petition%20CP%2016-1%20Floor
%20Coverings%20011817.pdf.
E:\FR\FM\06JNP1.SGM
06JNP1
]]>Agencies
[Federal Register Volume 83, Number 109 (Wednesday, June 6, 2018)]
[Proposed Rules]
[Pages 26226-26228]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-12077]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 29
[Docket No.FAA-2017-1127; Notice No. 29-044-SC]
Special Conditions: Bell Helicopter Textron, Inc. (BHTI), Model
525 Helicopters; Flight Envelope Protection
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed special conditions.
-----------------------------------------------------------------------
SUMMARY: This action proposes special conditions for the BHTI Model 525
helicopter. This helicopter will have a novel or unusual design feature
associated with fly-by-wire flight control system (FBW FCS) flight
envelope protection. The applicable airworthiness regulations do not
contain adequate or appropriate safety standards for this design
feature. These proposed special conditions contain the additional
safety standards that the Administrator considers necessary to
establish a level of safety equivalent to that established by the
existing airworthiness standards.
DATES: Send your comments on or before July 23, 2018.
ADDRESSES: Send comments identified by docket number [FAA-2017-1127]
using any of the following methods:
Federal eRegulations Portal: Go to https://www.regulations.gov and follow the online instructions for sending your
comments electronically.
Mail: Send comments to Docket Operations, M-30, U.S.
Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
Hand Delivery of Courier: Take comments to Docket
Operations in Room W12-140 of the West Building Ground Floor at 1200
New Jersey Avenue SE, Washington, DC, between 8 a.m., and 5 p.m.,
Monday through Friday, except Federal holidays.
Fax: Fax comments to Docket Operations at 202-493-2251.
Privacy: The FAA will post all comments it receives, without
change, to https://www.regulations.gov, including any personal
information the commenter provides. Using the search function of the
docket website, anyone can find and read the electronic form of all
comments received into any FAA docket, including the name of the
individual sending the comment (or signing the comment for an
association, business, labor union, etc.). DOT's complete Privacy Act
Statement can be found in the Federal Register published on April 11,
2000 (65 FR 19477-19478), as well as at https://DocketsInfo.dot.gov.
Docket: Background documents or comments received may be read at
https://www.regulations.gov at any time. Follow the online instructions
for accessing the docket or go to the Docket Operations in Room W12-140
of the West Building Ground Floor at 1200 New Jersey Avenue SE,
Washington, DC, between 9 a.m., and 5 p.m., Monday through Friday,
except Federal holidays.
FOR FURTHER INFORMATION CONTACT: George Harrum, Aerospace Engineer,
[[Page 26227]]
FAA, Rotorcraft Standards Branch, Policy and Innovation Division, 10101
Hillwood Pkwy, Fort Worth, TX 76177; telephone (817) 222-4087; email
[email protected].
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite interested people to take part in this rulemaking by
sending written comments, data, or views. The most helpful comments
reference a specific portion of the special conditions, explain the
reason for any recommended change, and include supporting data.
We will consider all comments we receive on or before the closing
date for comments. We will consider comments filed late if it is
possible to do so without incurring expense or delay. We may change
these special conditions based on the comments we receive.
Background
On December 15, 2011, BHTI applied for a type certificate for a new
transport category helicopter designated as the Model 525. The Model
525 is a medium twin-engine rotorcraft. The design maximum takeoff
weight is 20,500 pounds, with a maximum capacity of 19 passengers and a
crew of 2.
The BHTI Model 525 helicopter will be equipped with a four axis
full authority digital FBW FCS that provides for aircraft control
through pilot input and coupled flight director modes. The FBW FCS will
contain an advanced flight control system that will alter the nominal
flight control laws to ensure that the aircraft remains in a
predetermined flight envelope. These Flight Envelope Protection (FEP)
features prevent the pilot or autopilot functions from making control
commands that would force the aircraft to exceed its structural,
aerodynamic, or operating limits. The design and construction
standards, specifically 14 CFR 29.779(a), require that movement of the
flight controls results in a corresponding sense of aircraft motion in
the same axis. The airworthiness standards for an automatic pilot
system in Sec. 29.1329 covers design requirements for basic operation
of the system but does not address dynamic flight envelope limitations
imposed by the automatic pilot system. Currently there are no specific
airworthiness requirements that address FBW FCS FEP in rotorcraft. The
proposed special conditions will require the minimum safety standard
for the FEP features.
Type Certification Basis
Under the provisions of 14 CFR 21.17, BHTI must show that the Model
525 helicopter meets the applicable provisions of part 29, as amended
by Amendment 29-1 through 29-55 thereto. The BHTI Model 525
certification basis date is December 31, 2013, the effective date of
application to the FAA.
If the Administrator finds that the applicable airworthiness
regulations (i.e., 14 CFR part 29) do not contain adequate or
appropriate safety standards for the BHTI Model 525 because of a novel
or unusual design feature, special conditions are prescribed under the
provisions of Sec. 21.16.
Special conditions are initially applicable to the model for which
they are issued. Should the type certificate for that model be amended
later to include any other model that incorporates the same or similar
novel or unusual design feature, the special conditions would also
apply to the other model under Sec. 21.101.
In addition to the applicable airworthiness regulations and special
conditions, the BHTI Model 525 helicopter must comply with the noise
certification requirements of 14 CFR part 36, and the FAA must issue a
finding of regulatory adequacy under section 611 of Public Law 92-574,
the ``Noise Control Act of 1972.''
The FAA issues special conditions, as defined in 14 CFR 11.19, in
accordance with Sec. 11.38, and they become part of the type-
certification basis under Sec. 21.17(a)(2).
Novel or Unusual Design Features
The BHTI Model 525 helicopter will incorporate the following novel
or unusual design features: FBW FCS incorporating FEP features. FEP is
used to prevent the pilot or an autopilot from making control commands
that would force the rotorcraft to exceed its structural, aerodynamic,
or operating limits. To accomplish this envelope limiting, the FCS
control laws change as the limit is approached or exceeded.
Discussion
The proposed special conditions will require the minimum safety
standard for the flight envelope protection features. The FEP features
must meet requirements for handling qualities, compatibility of flight
parameter limit values, response to dynamic maneuvering, and failure
modes.
Applicability
As discussed above, these special conditions are applicable to the
BHTI Model 525 helicopter. Should BHTI apply at a later date for a
change to the type certificate to include another model incorporating
the same novel or unusual design feature, the special conditions would
apply to that model as well.
Conclusion
This action affects only certain novel or unusual design features
on one model of rotorcraft. It is not a rule of general applicability.
List of Subjects in 14 CFR Part 29
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.
The Proposed Special Conditions
Accordingly, the Federal Aviation Administration (FAA) proposes the
following special conditions as part of the type certification basis
for Bell Helicopter Textron, Inc., Model 525 helicopters:
Flight Envelope Protection
The Flight Envelope Protection (FEP) features of the FCS must meet
the following requirements:
a. Onset characteristics of each envelope protection feature must
be smooth, appropriate to the phase of flight and type of maneuver, and
not in conflict with the ability of the pilot to satisfactorily change
rotorcraft flight path, speed, or attitude within the approved flight
envelope.
b. Limit values of protected flight parameters (and if applicable,
associated warning thresholds) must be compatible with:
1. Rotorcraft structural limits;
2. Safe and controllable maneuvering of the rotorcraft;
3. Margins to critical conditions. Dynamic maneuvering, airframe
and system tolerances (both manufacturing and in-service), and non-
steady atmospheric conditions--in any appropriate combination and phase
of flight--must not result in a limited flight parameter beyond the
nominal design limit value that would cause unsafe flight
characteristics;
4. Rotor rotational speed limits;
5. Blade stall limits; and
6. Engine and transmission torque limits.
c. The aircraft must be responsive to pilot-commanded dynamic
maneuvering within a suitable range of the parameter limits that define
the approved flight envelope.
d. The FEP system must not create unusual or adverse flight
characteristics when atmospheric conditions or unintentional pilot
action causes the
[[Page 26228]]
approved flight envelope to be exceeded.
e. When simultaneous envelope limiting is active, adverse coupling
or adverse priority must not result.
f. Following a single FEP failure shown to not be extremely
improbable, the rotorcraft must:
1. Be capable of continued safe flight and landing;
2. Be capable of initial counteraction of malfunctions without
requiring exceptional pilot skill or strength;
3. Be controllable and maneuverable when operated with a degraded
FCS, within a practical flight envelope identified in the Rotorcraft
Flight Manual;
4. Be capable of prolonged instrument flight without requiring
exceptional pilot skill;
5. Meet the controllability and maneuverability requirements of 14
CFR part 29 Subpart B throughout a practical flight envelope; and
6. Be safely controllable following any additional failure or
malfunction shown to not be extremely improbable occurring within the
approved flight envelope.
Issued in Fort Worth, Texas, on May 24, 2018.
Jorge Castillo,
Acting Manager, Rotorcraft Standards Branch, Policy and Innovation
Division, Aircraft Certification Services.
[FR Doc. 2018-12077 Filed 6-5-18; 8:45 am]
BILLING CODE 4910-13-P
