Special Conditions: Dassault Aviation Model Falcon 6X Airplane; Electronic Flight-Control System: Lateral-Directional and Longitudinal Stability and Low-Energy Awareness, 8145-8147 [2022-03026]
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Federal Register / Vol. 87, No. 30 / Monday, February 14, 2022 / Rules and Regulations
Conclusion
This action affects only a certain
novel or unusual design feature on one
model of airplane. It is not a rule of
general applicability.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting
and recordkeeping requirements.
Authority Citation
The authority citation for these
special conditions is as follows:
BILLING CODE 4910–13–P
The Special Conditions
Accordingly, pursuant to the
authority delegated to me by the
Administrator, the following special
conditions are issued as part of the type
certification basis for Dassault Aviation
Model Falcon 6X airplanes.
jspears on DSK121TN23PROD with RULES1
General Limiting Requirements
a. Onset characteristics of each flightenvelope 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 airplane flight
path, speed, or attitude as needed.
b. Limit values of protected flight
parameters (and, if applicable,
associated warning thresholds) must be
compatible with the following:
1. Airplane structural limits,
2. Required safe and controllable
maneuvering of the airplane, and
3. Margins to critical conditions.
Unsafe flight characteristics/conditions
must not result if dynamic
maneuvering, airframe, and system
tolerances (both manufacturing and
inservice), and non-steady atmospheric
conditions, in any appropriate
combination and phase of flight, can
produce a limited flight parameter
beyond the nominal design limit value.
c. The airplane must be responsive to
intentional dynamic maneuvering to
within a suitable range of the parameter
limit. Dynamic characteristics such as
damping and overshoot must also be
appropriate for the flight-maneuver and
limit parameter in question.
d. When simultaneous envelope
limiting is engaged, adverse coupling or
adverse priority must not result.
Failure States
a. Electronic flight-control system
(EFCS) failures, including sensors, must
not result in a condition where a
parameter is limited to such a reduced
value that safe and controllable
maneuvering is no longer available.
b. The crew must be alerted by
suitable means if any change in
16:05 Feb 11, 2022
Jkt 256001
Issued in Kansas City, Missouri, on
February 8, 2022.
Patrick R. Mullen,
Manager, Technical Innovation Policy
Branch, Policy and Innovation Division,
Aircraft Certification Service.
[FR Doc. 2022–03025 Filed 2–11–22; 8:45 am]
Authority: 49 U.S.C. 106(f), 106(g), 40113,
44701, 44702, 44704.
VerDate Sep<11>2014
envelope limiting or maneuverability is
produced by single or multiple failures
of the EFCS not shown to be extremely
improbable.
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA–2020–1039; Special
Conditions No. 25–807–SC]
Special Conditions: Dassault Aviation
Model Falcon 6X Airplane; Electronic
Flight-Control System: LateralDirectional and Longitudinal Stability
and Low-Energy Awareness
Federal Aviation
Administration (FAA), Department of
Transportation (DOT).
ACTION: Final special conditions; request
for comments.
AGENCY:
These special conditions are
issued for the Dassault Aviation
(Dassault) Model Falcon 6X airplane.
This airplane will have a novel or
unusual design feature when compared
to the state of technology envisioned in
the airworthiness standards for
transport category airplanes. This design
feature is an electronic flight-control
system (EFCS) associated with lateraldirectional and longitudinal stability,
and low-energy awareness. The
applicable airworthiness regulations do
not contain adequate or appropriate
safety standards for this design feature.
These 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: This action is effective on
Dassault on February 14, 2022. Send
comments on or before March 31, 2022.
ADDRESSES: Send comments identified
by Docket No. FAA–2020–1039 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
SUMMARY:
PO 00000
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8145
Avenue SE, Room W12–140, West
Building Ground Floor, Washington, DC
20590–0001.
• Hand Delivery or 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 9
a.m. and 5 p.m., Monday through
Friday, except Federal holidays.
• Fax: Fax comments to Docket
Operations at 202–493–2251.
Privacy: Except for Confidential
Business Information (CBI) as described
in the following paragraph, and other
information as described in title 14,
Code of Federal Regulations (14 CFR)
11.35, the FAA will post all comments
received without change to https://
www.regulations.gov/, including any
personal information you provide. The
FAA will also post a report
summarizing each substantive verbal
contact received about these special
conditions.
Confidential Business Information:
Confidential Business Information (CBI)
is commercial or financial information
that is both customarily and actually
treated as private by its owner. Under
the Freedom of Information Act (FOIA)
(5 U.S.C. 552), CBI is exempt from
public disclosure. If your comments
responsive to these special conditions
contain commercial or financial
information that is customarily treated
as private, that you actually treat as
private, and that is relevant or
responsive to these special conditions, it
is important that you clearly designate
the submitted comments as CBI. Please
mark each page of your submission
containing CBI as ‘‘PROPIN.’’ The FAA
will treat such marked submissions as
confidential under the FOIA, and the
indicated comments will not be placed
in the public docket of these special
conditions. Send submissions
containing CBI to the Information
Contact below. Comments the FAA
receives, which are not specifically
designated as CBI, will be placed in the
public docket for this rulemaking.
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 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: Troy
Brown, Performance and Environment
Section, AIR–625, Technical Innovation
Policy Branch, Policy and Innovation
Division, Aircraft Certification Service,
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8146
Federal Register / Vol. 87, No. 30 / Monday, February 14, 2022 / Rules and Regulations
Federal Aviation Administration, 1801
S Airport Rd., Wichita, KS 67209–2190;
telephone and fax 405–666–1050; email
troy.a.brown@faa.gov.
SUPPLEMENTARY INFORMATION: The
substance of these special conditions
has been published in the Federal
Register for public comment in several
prior instances with no substantive
comments received. Therefore, the FAA
finds, pursuant to § 11.38(b), that new
comments are unlikely, and notice and
comment prior to this publication are
unnecessary.
Comments Invited
The FAA invites 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.
The FAA will consider all comments
received by the closing date for
comments. The FAA may change these
special conditions based on the
comments received.
jspears on DSK121TN23PROD with RULES1
Background
On July 1, 2012, Dassault applied for
a type certificate for its new Model
Falcon 5X airplane. However, Dassault
has decided not to release an airplane
under the model designation Falcon 5X,
instead choosing to change that model
designation to Falcon 6X.
In February of 2018, due to engine
supplier issues, Dassault extended the
type certificate application date for its
Model Falcon 5X airplane under new
Model Falcon 6X. This airplane is a
twin-engine business jet with seating for
19 passengers, and has a maximum
takeoff weight of 77,460 pounds.
Type Certification Basis
Under the provisions of 14 CFR 21.17,
Dassault must show that the Model
Falcon 6X airplane meets the applicable
provisions of part 25, as amended by
amendments 25–1 through 25–146.
If the Administrator finds that the
applicable airworthiness regulations
(e.g., 14 CFR part 25) do not contain
adequate or appropriate safety standards
for the Dassault Model Falcon 6X
airplane 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 novel or unusual
design feature, these special conditions
VerDate Sep<11>2014
16:05 Feb 11, 2022
Jkt 256001
would also apply to the other model
under § 21.101.
In addition to the applicable
airworthiness regulations and special
conditions, the Dassault Model Falcon
6X airplane must comply with the fuelvent and exhaust-emission requirements
of 14 CFR part 34, and the noisecertification requirements of 14 CFR
part 36.
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 Dassault Model Falcon 6X
airplane will incorporate the following
novel or unusual design features:
Lateral-directional and longitudinal
stability, and low-energy awareness,
functions of the EFCS.
Discussion
Lateral-directional Static Stability:
The Dassault Model 6X airplane
includes a flight-control design feature
within the normal operational envelope
in which side-stick deflection in the roll
axis commands roll rate; and stick force
in the roll axis will be zero (neutral
stability) during the straight, steady
sideslip flight maneuver required by
§ 25.177(c), which will not be
‘‘substantially proportional to the angle
of sideslip’’ as required by the rule.
Longitudinal Static Stability: The
longitudinal flight control laws for the
Model Falcon 6X airplane provide
neutral static stability within the normal
operational envelope; therefore, the
airplane design does not comply with
the static longitudinal stability
requirements of §§ 25.171, 25.173, and
25.175.
Low Energy Awareness: Static
longitudinal stability provides
awareness to the flight crew when they
have deviated from a trimmed state.
This could also be an important factor
in their awareness of a low energy state
(low speed and thrust at low altitude) if
they are flying at low speeds. Entry into
a low energy state may be less
noticeable due to this lack of static
stability and recovery may become more
hazardous when associated with a low
altitude and performance limiting
conditions. These low energy situations
must therefore be avoided, and pilots
must be given adequate cues when
approaching such situations.
The EFCS affects the following
stability and energy-awareness features
of the airplane:
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1. Lateral-Directional Static Stability
The EFCS on the Dassault Model
Falcon 6X contains fly-by-wire control
laws that can result in neutral lateraldirectional static stability. Therefore,
the airplane does not meet the
conventional requirements in the
regulations.
Positive static directional stability is
defined as the tendency to recover from
a skid with the rudder free. Positive
static lateral stability is defined as the
tendency to raise the low wing in a
sideslip with the aileron controls free.
These control criteria are intended to
accomplish the following:
a. Provide additional cues of
inadvertent sideslips and skids through
control-force changes.
b. Ensure that short periods of
unattended operation do not result in
any significant changes in yaw or bank
angle.
c. Provide predictable roll and yaw
response.
d. Provide an acceptable level of pilot
attention (workload) to attain and
maintain a coordinated turn.
2. Static Longitudinal Stability
Static longitudinal stability on
airplanes with mechanical links to the
pitch-control surface means that a pull
force on the controller results in a
reduction in speed relative to the trim
speed, and a push force results in higher
than trim speed. Longitudinal stability
is required by the regulations for the
following reasons:
a. Speed-change cues are provided to
the pilot through increased and
decreased forces on the controller.
b. Short periods of unattended control
of the airplane do not result in
significant changes in attitude, airspeed,
or load factor.
c. A predictable pitch response is
provided to the pilot.
d. An acceptable level of pilot
attention (workload) to attain and
maintain trim speed and altitude is
provided to the pilot.
e. Longitudinal stability provides gust
stability.
The pitch-control movement of the
side stick on the Model Falcon 6X
airplane is designed to be a normal load
factor, or ‘‘g’’ command, that results in
an initial movement of the elevator
surface to attain the commanded load
factor that is then followed by integrated
movement of the stabilizer and elevator
to automatically trim the airplane to a
neutral, 1g, stick-free stability. The
flight path commanded by the initial
side-stick input will remain, stick-free,
until the pilot provides another
command. This control function is
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Federal Register / Vol. 87, No. 30 / Monday, February 14, 2022 / Rules and Regulations
applied during ‘‘normal’’ control law
within the speed range, from initiation
of the angle-of-attack protection limit,
Vprot, to VMO/MMO. Once outside this
speed range, the control laws introduce
the conventional longitudinal static
stability as described above.
As a result of neutral static stability,
the Model Falcon 6X airplane does not
meet the regulatory requirements for
static longitudinal stability.
3. Low Energy Awareness
Past experience on airplanes fitted
with a flight-control system providing
neutral longitudinal stability reveals
insufficient feedback cues to the pilot of
excursion below normal operational
speeds. The maximum angle-of-attack
protection system limits the airplane
angle of attack and prevents stall during
normal operating speeds, but this
system is not sufficient to prevent stall
at low-speed excursions below normal
operational speeds. Until intervention,
there are no stability cues because the
aircraft remains trimmed. Additionally,
feedback from the pitching moment due
to thrust variation is reduced by the
flight-control laws. Low-speed
excursions may become more hazardous
without the typical longitudinal
stability, and recovery is more difficult
when the low-speed situation is
associated with a low altitude, and with
the engines at low thrust or with
performance-limiting conditions.
These 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.
Applicability
As discussed above, these special
conditions are applicable to the Dassault
Model Falcon 6X airplane. Should
Dassault apply at a later date for a
change to the type certificate to include
another model incorporating the same
novel or unusual design feature, these
special conditions would apply to that
model as well.
Conclusion
jspears on DSK121TN23PROD with RULES1
This action affects only a certain
novel or unusual design feature on one
model of airplane. It is not a rule of
general applicability.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting
and recordkeeping requirements.
Authority Citation
The authority citation for these
special conditions is as follows:
VerDate Sep<11>2014
16:05 Feb 11, 2022
Jkt 256001
Authority: 49 U.S.C. 106(f), 106(g), 40113,
44701, 44702, 44704.
Accordingly, pursuant to the
authority delegated to me by the
Administrator, the following special
conditions are issued as part of the type
certification basis for the Dassault
Aviation Model Falcon 6X airplane.
In lieu of the requirements of
§§ 25.171, 25.173, 25.175, and 25.177(c),
the following special conditions apply:
1. The airplane must be shown to
have suitable static lateral, directional,
and longitudinal stability in any
condition normally encountered in
service, including the effects of
atmospheric disturbance. The showing
of suitable static lateral, directional, and
longitudinal stability must be based on
the airplane handling qualities,
including pilot workload and pilot
compensation, for specific test
procedures during the flight-test
evaluations.
2. The airplane must provide
adequate awareness to the pilot of a low
energy (low speed, low thrust, low
height) state when fitted with flightcontrol laws presenting neutral
longitudinal stability significantly
below the normal operating speeds.
‘‘Adequate awareness’’ means warning
information must be provided to alert
the crew of unsafe operating conditions,
and to enable them to take appropriate
corrective action.
3. The following requirement must be
met for the configurations and speed
specified in paragraph (a) of § 25.177. In
straight, steady sideslips over the range
of sideslip angles appropriate to the
operation of the airplane, the ruddercontrol movements and forces must be
substantially proportional to the angle
of sideslip in a stable sense. This factor
of proportionality must lie between
limits found necessary for safe
operation. The range of sideslip angles
evaluated must include those sideslip
angles resulting from the lesser of:
a. One-half of the available rudder
control input; and
b. A rudder control force of 180
pounds.
Issued in Kansas City, Missouri, on
February 8, 2022.
Patrick R. Mullen,
Manager, Technical Innovation Policy
Branch, Policy and Innovation Division,
Aircraft Certification Service.
[FR Doc. 2022–03026 Filed 2–11–22; 8:45 am]
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Fmt 4700
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
The Special Conditions
BILLING CODE 4910–13–P
8147
14 CFR Part 25
[Docket No. FAA–2021–1023; Special
Conditions No. 25–811–SC]
Special Conditions: The Boeing
Company, Model 737–10 Airplane;
Dynamic Test Requirements for SingleOccupant, Oblique (Side-Facing) Seats
Installed at 49 Degrees With Airbag
Devices and 3-Point Restraints
Federal Aviation
Administration (FAA), Department of
Transportation (DOT).
ACTION: Final special conditions.
AGENCY:
These special conditions are
issued for The Boeing Company
(Boeing) Model 737–10 airplane. This
airplane will have a novel or unusual
design feature when compared to the
state of technology envisioned in the
airworthiness standards for transportcategory airplanes. This design feature
is single-occupant oblique seats with
airbag devices and 3-point restraints,
installed at 49 degrees relative to the
airplane cabin bow-to-stern centerline.
The applicable airworthiness
regulations do not contain adequate or
appropriate safety standards for this
design feature. These 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: Effective February 14, 2022.
FOR FURTHER INFORMATION CONTACT: John
Shelden, Human Machine Interface
Section, AIR–626, Technical Innovation
Policy Branch, Policy and Innovation
Division, Aircraft Certification Service,
Federal Aviation Administration, 2200
South 216th Street, Des Moines,
Washington 98198; telephone and fax
206–231–3214; email john.shelden@
faa.gov.
SUMMARY:
SUPPLEMENTARY INFORMATION:
Background
On January 30, 2019, Boeing applied
for a change to Type Certificate No.
A16WE for the installation of singleoccupant oblique seats, with airbag
devices and 3-point restraints, installed
at 49 degrees relative to the airplane
cabin bow-to-stern centerline in the
Boeing Model 737–10 airplane. The
Boeing Model 737–10 airplane is a twinengine, transport-category airplane with
seating for 230 passengers and a
maximum takeoff weight of 197,900
pounds.
E:\FR\FM\14FER1.SGM
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]]>Agencies
[Federal Register Volume 87, Number 30 (Monday, February 14, 2022)]
[Rules and Regulations]
[Pages 8145-8147]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-03026]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2020-1039; Special Conditions No. 25-807-SC]
Special Conditions: Dassault Aviation Model Falcon 6X Airplane;
Electronic Flight-Control System: Lateral-Directional and Longitudinal
Stability and Low-Energy Awareness
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Final special conditions; request for comments.
-----------------------------------------------------------------------
SUMMARY: These special conditions are issued for the Dassault Aviation
(Dassault) Model Falcon 6X airplane. This airplane will have a novel or
unusual design feature when compared to the state of technology
envisioned in the airworthiness standards for transport category
airplanes. This design feature is an electronic flight-control system
(EFCS) associated with lateral-directional and longitudinal stability,
and low-energy awareness. The applicable airworthiness regulations do
not contain adequate or appropriate safety standards for this design
feature. These 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: This action is effective on Dassault on February 14, 2022. Send
comments on or before March 31, 2022.
ADDRESSES: Send comments identified by Docket No. FAA-2020-1039 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 or 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 9 a.m. and 5 p.m., Monday
through Friday, except Federal holidays.
Fax: Fax comments to Docket Operations at 202-493-2251.
Privacy: Except for Confidential Business Information (CBI) as
described in the following paragraph, and other information as
described in title 14, Code of Federal Regulations (14 CFR) 11.35, the
FAA will post all comments received without change to https://www.regulations.gov/, including any personal information you provide.
The FAA will also post a report summarizing each substantive verbal
contact received about these special conditions.
Confidential Business Information: Confidential Business
Information (CBI) is commercial or financial information that is both
customarily and actually treated as private by its owner. Under the
Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from
public disclosure. If your comments responsive to these special
conditions contain commercial or financial information that is
customarily treated as private, that you actually treat as private, and
that is relevant or responsive to these special conditions, it is
important that you clearly designate the submitted comments as CBI.
Please mark each page of your submission containing CBI as ``PROPIN.''
The FAA will treat such marked submissions as confidential under the
FOIA, and the indicated comments will not be placed in the public
docket of these special conditions. Send submissions containing CBI to
the Information Contact below. Comments the FAA receives, which are not
specifically designated as CBI, will be placed in the public docket for
this rulemaking.
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 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: Troy Brown, Performance and
Environment Section, AIR-625, Technical Innovation Policy Branch,
Policy and Innovation Division, Aircraft Certification Service,
[[Page 8146]]
Federal Aviation Administration, 1801 S Airport Rd., Wichita, KS 67209-
2190; telephone and fax 405-666-1050; email [email protected].
SUPPLEMENTARY INFORMATION: The substance of these special conditions
has been published in the Federal Register for public comment in
several prior instances with no substantive comments received.
Therefore, the FAA finds, pursuant to Sec. 11.38(b), that new comments
are unlikely, and notice and comment prior to this publication are
unnecessary.
Comments Invited
The FAA invites 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.
The FAA will consider all comments received by the closing date for
comments. The FAA may change these special conditions based on the
comments received.
Background
On July 1, 2012, Dassault applied for a type certificate for its
new Model Falcon 5X airplane. However, Dassault has decided not to
release an airplane under the model designation Falcon 5X, instead
choosing to change that model designation to Falcon 6X.
In February of 2018, due to engine supplier issues, Dassault
extended the type certificate application date for its Model Falcon 5X
airplane under new Model Falcon 6X. This airplane is a twin-engine
business jet with seating for 19 passengers, and has a maximum takeoff
weight of 77,460 pounds.
Type Certification Basis
Under the provisions of 14 CFR 21.17, Dassault must show that the
Model Falcon 6X airplane meets the applicable provisions of part 25, as
amended by amendments 25-1 through 25-146.
If the Administrator finds that the applicable airworthiness
regulations (e.g., 14 CFR part 25) do not contain adequate or
appropriate safety standards for the Dassault Model Falcon 6X airplane
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 novel or
unusual design feature, these special conditions would also apply to
the other model under Sec. 21.101.
In addition to the applicable airworthiness regulations and special
conditions, the Dassault Model Falcon 6X airplane must comply with the
fuel-vent and exhaust-emission requirements of 14 CFR part 34, and the
noise-certification requirements of 14 CFR part 36.
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 Dassault Model Falcon 6X airplane will incorporate the
following novel or unusual design features:
Lateral-directional and longitudinal stability, and low-energy
awareness, functions of the EFCS.
Discussion
Lateral-directional Static Stability: The Dassault Model 6X
airplane includes a flight-control design feature within the normal
operational envelope in which side-stick deflection in the roll axis
commands roll rate; and stick force in the roll axis will be zero
(neutral stability) during the straight, steady sideslip flight
maneuver required by Sec. 25.177(c), which will not be ``substantially
proportional to the angle of sideslip'' as required by the rule.
Longitudinal Static Stability: The longitudinal flight control laws
for the Model Falcon 6X airplane provide neutral static stability
within the normal operational envelope; therefore, the airplane design
does not comply with the static longitudinal stability requirements of
Sec. Sec. 25.171, 25.173, and 25.175.
Low Energy Awareness: Static longitudinal stability provides
awareness to the flight crew when they have deviated from a trimmed
state. This could also be an important factor in their awareness of a
low energy state (low speed and thrust at low altitude) if they are
flying at low speeds. Entry into a low energy state may be less
noticeable due to this lack of static stability and recovery may become
more hazardous when associated with a low altitude and performance
limiting conditions. These low energy situations must therefore be
avoided, and pilots must be given adequate cues when approaching such
situations.
The EFCS affects the following stability and energy-awareness
features of the airplane:
1. Lateral-Directional Static Stability
The EFCS on the Dassault Model Falcon 6X contains fly-by-wire
control laws that can result in neutral lateral-directional static
stability. Therefore, the airplane does not meet the conventional
requirements in the regulations.
Positive static directional stability is defined as the tendency to
recover from a skid with the rudder free. Positive static lateral
stability is defined as the tendency to raise the low wing in a
sideslip with the aileron controls free. These control criteria are
intended to accomplish the following:
a. Provide additional cues of inadvertent sideslips and skids
through control-force changes.
b. Ensure that short periods of unattended operation do not result
in any significant changes in yaw or bank angle.
c. Provide predictable roll and yaw response.
d. Provide an acceptable level of pilot attention (workload) to
attain and maintain a coordinated turn.
2. Static Longitudinal Stability
Static longitudinal stability on airplanes with mechanical links to
the pitch-control surface means that a pull force on the controller
results in a reduction in speed relative to the trim speed, and a push
force results in higher than trim speed. Longitudinal stability is
required by the regulations for the following reasons:
a. Speed-change cues are provided to the pilot through increased
and decreased forces on the controller.
b. Short periods of unattended control of the airplane do not
result in significant changes in attitude, airspeed, or load factor.
c. A predictable pitch response is provided to the pilot.
d. An acceptable level of pilot attention (workload) to attain and
maintain trim speed and altitude is provided to the pilot.
e. Longitudinal stability provides gust stability.
The pitch-control movement of the side stick on the Model Falcon 6X
airplane is designed to be a normal load factor, or ``g'' command, that
results in an initial movement of the elevator surface to attain the
commanded load factor that is then followed by integrated movement of
the stabilizer and elevator to automatically trim the airplane to a
neutral, 1g, stick-free stability. The flight path commanded by the
initial side-stick input will remain, stick-free, until the pilot
provides another command. This control function is
[[Page 8147]]
applied during ``normal'' control law within the speed range, from
initiation of the angle-of-attack protection limit, Vprot,
to VMO/MMO. Once outside this speed range, the
control laws introduce the conventional longitudinal static stability
as described above.
As a result of neutral static stability, the Model Falcon 6X
airplane does not meet the regulatory requirements for static
longitudinal stability.
3. Low Energy Awareness
Past experience on airplanes fitted with a flight-control system
providing neutral longitudinal stability reveals insufficient feedback
cues to the pilot of excursion below normal operational speeds. The
maximum angle-of-attack protection system limits the airplane angle of
attack and prevents stall during normal operating speeds, but this
system is not sufficient to prevent stall at low-speed excursions below
normal operational speeds. Until intervention, there are no stability
cues because the aircraft remains trimmed. Additionally, feedback from
the pitching moment due to thrust variation is reduced by the flight-
control laws. Low-speed excursions may become more hazardous without
the typical longitudinal stability, and recovery is more difficult when
the low-speed situation is associated with a low altitude, and with the
engines at low thrust or with performance-limiting conditions.
These 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.
Applicability
As discussed above, these special conditions are applicable to the
Dassault Model Falcon 6X airplane. Should Dassault apply at a later
date for a change to the type certificate to include another model
incorporating the same novel or unusual design feature, these special
conditions would apply to that model as well.
Conclusion
This action affects only a certain novel or unusual design feature
on one model of airplane. It is not a rule of general applicability.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
Authority Citation
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701, 44702, 44704.
The Special Conditions
Accordingly, pursuant to the authority delegated to me by the
Administrator, the following special conditions are issued as part of
the type certification basis for the Dassault Aviation Model Falcon 6X
airplane.
In lieu of the requirements of Sec. Sec. 25.171, 25.173, 25.175,
and 25.177(c), the following special conditions apply:
1. The airplane must be shown to have suitable static lateral,
directional, and longitudinal stability in any condition normally
encountered in service, including the effects of atmospheric
disturbance. The showing of suitable static lateral, directional, and
longitudinal stability must be based on the airplane handling
qualities, including pilot workload and pilot compensation, for
specific test procedures during the flight-test evaluations.
2. The airplane must provide adequate awareness to the pilot of a
low energy (low speed, low thrust, low height) state when fitted with
flight-control laws presenting neutral longitudinal stability
significantly below the normal operating speeds. ``Adequate awareness''
means warning information must be provided to alert the crew of unsafe
operating conditions, and to enable them to take appropriate corrective
action.
3. The following requirement must be met for the configurations and
speed specified in paragraph (a) of Sec. 25.177. In straight, steady
sideslips over the range of sideslip angles appropriate to the
operation of the airplane, the rudder-control movements and forces must
be substantially proportional to the angle of sideslip in a stable
sense. This factor of proportionality must lie between limits found
necessary for safe operation. The range of sideslip angles evaluated
must include those sideslip angles resulting from the lesser of:
a. One-half of the available rudder control input; and
b. A rudder control force of 180 pounds.
Issued in Kansas City, Missouri, on February 8, 2022.
Patrick R. Mullen,
Manager, Technical Innovation Policy Branch, Policy and Innovation
Division, Aircraft Certification Service.
[FR Doc. 2022-03026 Filed 2-11-22; 8:45 am]
BILLING CODE 4910-13-P
