Special Conditions: Gulfstream Aerospace Corporation Model GVIII-G700 and GVIII-G800 Airplanes; Flight Envelope Protection: High-Incidence Protection System (Non-Icing and Icing Conditions), 17276-17281 [2024-05043]
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Federal Register / Vol. 89, No. 48 / Monday, March 11, 2024 / Rules and Regulations
Subpart B—Operations and
Maintenance Requirements
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
18. Revise § 1730.24 to read as
follows:
14 CFR Part 25
§ 1730.24
[Docket No. FAA–2023–2441; Special
Conditions No. 25–853–SC]
■
RUS review and evaluation.
RUS will initiate and conduct a
periodic review and evaluation of the
operations and maintenance practices of
each borrower for the purpose of
assessing loan security and determining
borrower compliance with RUS policy
as outlined in this part. This review will
normally be done at least once every
four years for all Borrowers. The
borrower will make available to RUS the
borrower’s policies, procedures, and
records related to the operations and
maintenance of its complete system.
Reports made by other inspectors (e.g.,
other Federal agencies, State inspectors,
etc.) will also be made available, as
applicable. RUS will not duplicate these
other reviews but will use their reports
to supplement its own review. RUS may
inspect facilities, as well as records, and
may also observe construction and
maintenance work in the field. Key
borrower personnel responsible for the
facilities being inspected are to
accompany RUS during such
inspections, unless otherwise
determined by RUS. RUS personnel may
prepare an independent summary of the
operations and maintenance practices of
the borrower. The borrower’s
management will discuss this review
and evaluation with its Board of
Directors.
Subpart C—Interconnection of
Distributed Resources
19. Revise § 1730.100 to read as
follows:
■
§ 1730.100
OMB control number.
The information collection
requirements in this part are approved
by the Office of Management and
Budget and assigned OMB control
number 0572–0025.
Andrew Berke,
Administrator, Rural Utilities Service.
[FR Doc. 2024–05076 Filed 3–8–24; 8:45 am]
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Special Conditions: Gulfstream
Aerospace Corporation Model GVIII–
G700 and GVIII–G800 Airplanes; Flight
Envelope Protection: High-Incidence
Protection System (Non-Icing and Icing
Conditions)
Federal Aviation
Administration (FAA), DOT.
ACTION: Final special conditions; request
for comments.
AGENCY:
These special conditions are
issued for the Gulfstream Aerospace
Corporation (Gulfstream) Model GVIII–
G700 and GVIII–G800 series airplanes.
These airplanes 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 a high-incidence
protection system that limits the angle
of attack at which the airplane can be
flown during normal low speed
operation. 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 date: This action is effective
on Gulfstream on March 11, 2024.
Comments due date: Send comments
on or before April 25, 2024.
ADDRESSES: Send comments identified
by Docket No. FAA–2023–2441 using
any of the following methods:
• Federal eRegulations Portal: Go to
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.
SUMMARY:
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• Docket: Background documents or
comments received may be read at
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
Unit, AIR–621A, Technical Policy
Branch, Policy and Standards Division,
Aircraft Certification Service, Federal
Aviation Administration, 1801 S Airport
Rd., Wichita, KS 67209–2190; telephone
405–666–1050; email troy.a.brown@
faa.gov.
The
anticipated delivery date for these
airplane models is imminent. Therefore,
the FAA finds, pursuant to 14 CFR
11.38(a), that prior notice and comments
would significantly delay delivery of the
affected aircraft, so notice and comment
prior to this publication are
impracticable. Therefore, the FAA is
issuing these special conditions as final,
request for comments.
SUPPLEMENTARY INFORMATION:
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
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
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conditions. Send submissions
containing CBI to the individual listed
in the FOR FURTHER INFORMATION
CONTACT section above. Comments the
FAA receives, which are not specifically
designated as CBI, will be placed in the
public docket for these special
conditions.
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 and will consider comments
filed late if it is possible to do so
without incurring delay. The FAA may
change these special conditions based
on the comments received.
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Background
On December 31, 2019, Gulfstream
applied for an amendment to Type
Certificate No. T00015AT to include the
new Model GVIII–G700 and GVIII–G800
series airplanes. These airplanes, which
are derivatives of the Model GVI
currently approved under Type
Certificate No. T00015AT, are twinengine, transport-category airplanes,
with seating for 19 passengers, and a
maximum take-off weight of 107,600
(GVIII–G700) pounds and 105,600
pounds (GVIII–G800).
Type Certification Basis
Under the provisions of title 14, Code
of Federal Regulations (14 CFR) 21.101,
Gulfstream must show that the Model
GVIII–G700 and GVIII–G800 series
airplanes meet the applicable provisions
of the regulations listed in Type
Certificate No. T00015AT, or the
applicable regulations in effect on the
date of application for the change,
except for earlier amendments as agreed
upon by the FAA.
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 Gulfstream Model GVIII–G700
and GVIII–G800 series airplanes 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, or should any other
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model already included on the same
type certificate be modified to
incorporate the same novel or unusual
design feature, these special conditions
would also apply to the other model
under § 21.101.
In addition to the applicable
airworthiness regulations and special
conditions, the Gulfstream Model
GVIII–G700 and GVIII–G800 series
airplanes must comply with the
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 14 CFR 11.38, and they become
part of the type certification basis under
§ 21.101.
Novel or Unusual Design Features
The Gulfstream Model GVIII–G700
and GVIII–G800 airplanes will
incorporate the following novel or
unusual design feature:
A high-incidence protection system
that limits the angle of attack at which
the airplane can be flown during normal
low speed operation, prohibits the
airplane from stalling, and cannot be
overridden by the flightcrew. The
application of this angle of attack limit
influences the stall speed
determination, stall characteristics, stall
warning demonstration, and the
longitudinal handling characteristics of
the airplane. Existing airworthiness
regulations do not contain adequate
standards to address this feature.
Discussion
The high-incidence protection system
prevents the airplane from stalling at
low speeds and, therefore, a stall
warning system is not needed during
normal flight conditions. However,
during failures, which are not shown to
be extremely improbable, the
requirements of §§ 25.203 and 25.207
apply, although slightly modified by
these conditions. If there are failures of
the high-incidence protection system
that are not shown to be extremely
improbable, the flight characteristics at
the angle of attack for CLMAX must be
suitable in the traditional sense, and
stall warning must be provided in a
conventional manner.
Part I of the special conditions is in
lieu of §§ 25.21(b), 25.103, 25.145(a),
25.145(b)(6), 25.175(c) and (d), 25.201,
25.203, 25.207, and 25.1323(d). Part II is
in lieu of §§ 25.21(g)(1), 25.105(a)(2)(i),
25.107(c) and (g), 25.121(b)(2)(ii)(A),
25.121(c)(2)(ii)(A), 25.121(d)(2)(ii),
25.123(b)(2)(i), 25.125(b)(2)(ii)(B), and
25.143(j).
These special conditions are different
from previously issued special
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conditions on this topic. Previously
used verbiage was updated to reflect
language recommended in the Aviation
Rulemaking Advisory Committee
(ARAC) Flight Test Harmonization
Working Group (FTHWG) Phase 2
report. This language more accurately
describes the actions require and
formulas to be used to obtain the
required result. In certain parts, the
ARAC FTHWG language was adapted to
further reflect specific Gulfstream
design features such as flight envelope
protection functions.
These special conditions address this
novel or unusual design feature on the
Gulfstream Model GVIII–G700 and
GVIII–G800 series airplanes and 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
Gulfstream Model GVIII–G700 and
GVIII–G800 series airplanes. Should
Gulfstream apply at a later date for a
change to the type certificate to include
another model that incorporates the
same novel or unusual design feature, or
should any other model already
included on the same type certificate be
modified to incorporate the same novel
or unusual design feature, these special
conditions would apply to the other
model as well.
Conclusion
This action affects only certain novel
or unusual design features on
Gulfstream Model GVIII–G700 and
GVIII–G800 series of airplanes. 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, and 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 Gulfstream Model
GVIII–G700 and GVIII–G800 series
airplanes.
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1. Definitions
These special conditions use
terminology that does not appear in 14
CFR part 25. For the purpose of these
special conditions, the following terms
describe certain aspects of this novel or
unusual design feature:
High-Incidence Protection System
A system that operates directly and
automatically on the airplane’s flight
controls to limit the maximum angle of
attack that can be attained to a value
below that at which an aerodynamic
stall would occur.
Alpha Limit
The maximum angle of attack at
which an airplane stabilizes with the
high-incidence protection system
operating and the longitudinal control
held on its aft stop.
VMIN
The minimum steady flight speed in
the airplane’s configuration under
consideration with the high-incidence
protection system operating. See Part I,
Section 3, ‘‘Minimum Steady Flight
Speed and Reference Stall Speed,’’ of
these special conditions.
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VMIN1g
VMIN corrected to 1g acceleration of
gravity conditions. See Part I, Section 3,
‘‘Minimum Steady Flight Speed and
Reference Stall Speed,’’ of these special
conditions. This is the minimum
calibrated airspeed at which the
airplane can develop a lift force normal
to the flight path and equal to its weight
when at an angle of attack not greater
than that determined for VMIN.
2. Capability and Reliability of the HighIncidence Protection System
The applicant must establish the
capability and reliability of the highincidence protection system. The
applicant may establish this capability
and reliability by flight testing,
simulation, or analysis as appropriate.
The capability and reliability required
are:
a. It must not be possible to encounter
a stall during the pilot-induced
maneuvers required by Part I, section
5(a), ‘‘High Incidence Handling
Demonstrations,’’ and the handling
characteristics must be acceptable as
required by Part I, section 5(b),
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‘‘Characteristics in High Incidence
Maneuvers’’ of these special conditions;
b. The airplane must be protected
against stalling due to the effects of
wind shears and gusts at low speeds as
required by Section 6, ‘‘Atmospheric
Disturbances’’ of these special
conditions;
c. The ability of the high-incidence
protection system to accommodate any
reduction in stalling incidence must be
verified in icing conditions;
d. The high-incidence protection
system must be provided in each
abnormal configuration of the high lift
devices that is likely to be used in flight
following system failures; and
e. The reliability of the system and the
effects of failures must be acceptable in
accordance with § 25.1309.
3. Minimum Steady Flight Speed and
Reference Stall Speed
In lieu of § 25.103, ‘‘Stall speed,’’ the
following applies:
a. The minimum steady flight speed,
VMIN, is the final, stabilized, calibrated
airspeed obtained when an airplane is
decelerated until the longitudinal
control is on its stop in such a way that
the entry rate does not exceed 1 knot per
second.
b. The minimum steady flight speed,
VMIN, must be determined in icing and
non-icing conditions with:
i. The high-incidence protection
system operating normally;
ii. Idle thrust and automatic thrust
system (if applicable) inhibited;
iii. All combinations of flap settings
and landing gear positions for which
VMIN is required to be determined;
iv. The weight used when the
reference stall speed, VSR, is used as a
factor to determine compliance with a
required performance standard;
v. The most unfavorable center of
gravity (CG) allowable; and
vi. The airplane trimmed for straight
flight at a speed selected by the
applicant, but not less than 1.13 VSR and
not greater than 1.3 VSR.
c. The 1g minimum steady flight
speed, VMIN1g, is the minimum
calibrated airspeed at which an airplane
can develop a lift force (normal to the
flight path) equal to its weight, while at
an angle of attack not greater than that
at which the minimum steady flight
speed referenced in section 3(a) of this
special condition is determined. These
minimum calibrated airspeeds must be
determined for both icing and non-icing
conditions.
d. The reference stall speed, VSR, is a
calibrated airspeed defined by the
applicant. VSR may not be less than a 1g
stall speed. VSR must be determined in
non-icing conditions and expressed as:
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Where:
VCLMAX = calibrated airspeed obtained when
the load factor-corrected lift coefficient
is first a maximum during the maneuver
prescribed in section 3(e)(vii) of this
special condition.
nZW = Load factor normal to the flight path
at VCLMAX
W = Airplane gross weight;
S = Aerodynamic reference wing area; and
q = Dynamic pressure.
e. VCLMAX is determined in non-icing
conditions with:
i. Engines idling, or, if that resultant
thrust causes an appreciable decrease in
stall speed, not more than zero thrust at
the stall speed;
ii. The airplane in other respects
(such as flaps and landing gear) in the
condition existing in the test or
performance standard in which VSR is
being used;
iii. The weight used when VSR is
being used as a factor to determine
compliance with a required
performance standard;
iv. The CG position that results in the
highest value of the reference stall
speed;
v. The airplane trimmed for straight
flight at a speed selected by the
applicant, but not less than 1.13 VSR and
not greater than 1.3 VSR;
vi. The high-incidence protection
system adjusted, at the option of the
applicant, to allow high incidence than
is possible with the normal production
system; and
vii. Starting from the stabilized trim
condition, with an application of the
longitudinal control to decelerate the
airplane so that the speed reduction
does not exceed 1 knot per second.
4. Stall Warning
In lieu of § 25.207, the following
apply:
a. Normal Operation
If the design meets all conditions of
Part I, section 2 of these special
conditions, then the airplane need not
provide stall warning during normal
operation. The conditions of Part I,
section 2 provide a level of safety equal
to the intent of § 25.207, ‘‘Stall
warning,’’ so the provision of an
additional, unique warning device for
normal operations is not required.
b. High-Incidence Protection System
Failure
For any failures of the high-incidence
protection system that the applicant
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Part I: Stall Protection and Scheduled
Operating Speeds
In the following sections, ‘‘in icing
conditions,’’ means with ice accretions
(relative to the relevant flight phase) as
defined in appendix C to part 25, at
amendment 25–121.
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cannot show to be extremely
improbable, and that result in the
capability of the system no longer
satisfying any part of sections 2(a), (b),
and (c) of Part I of these special
conditions: The design must provide
stall warning that protects against
encountering unacceptable
characteristics and against encountering
stall.
i. This stall warning, with the flaps
and landing gear in any normal
position, must be clear and distinctive
to the pilot, and must meet the
requirements specified in sections
4(b)(iv) and 4(b)(v) of Part I of these
special conditions.
ii. The design must also provide this
stall warning in each abnormal
configuration of the high lift devices
that is likely to be used in flight
following system failures.
iii. The design may furnish this stall
warning either through the inherent
aerodynamic qualities of the airplane or
by a device that will provide clearly
distinguishable indications to the
flightcrew under all expected conditions
of flight. However, a visual stall warning
device that requires the attention of the
flightcrew within the flight deck is not
acceptable by itself. If a warning device
is used, it must provide a warning in
each of the airplane configurations
prescribed in section 4(b)(i), above, and
for the conditions prescribed in sections
4(b)(iv) and 4(b)(v) of part I of these
special conditions.
iv. In non-icing conditions, the stall
warning must provide sufficient margin
to prevent encountering unacceptable
characteristics and encountering stall in
the following conditions:
1. In power-off straight deceleration
not exceeding 1 knot per second to a
speed of 5 knots or 5 percent calibrated
airspeed (CAS), whichever is greater,
below the warning onset; and
2. In turning flight, stall deceleration
at entry rates up to 3 knots per second
when recovery is initiated not less than
1 second after the warning onset.
v. In icing conditions, the stall
warning must provide sufficient margin
to prevent encountering unacceptable
characteristics and encountering stall in
power-off straight and turning flight
decelerations not exceeding 1 knot per
second, when the pilot starts a recovery
maneuver not less than three seconds
after the onset of stall warning.
vi. An airplane is considered stalled
when the behavior of the airplane gives
the pilot a clear, distinctive, and
acceptable indication that the airplane
is stalled. Acceptable indications of a
stall, occurring either individually or in
combination, are:
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1. A nose-down pitch that cannot be
readily arrested;
2. Buffeting of a magnitude and
severity that is strong and thereby an
effective deterrent to further speed
reduction; or
3. The pitch control reaches the aft
stop, and no further increase in pitch
attitude occurs when the control is held
full aft for a short time before recovery
is initiated.
vii. An airplane exhibits unacceptable
characteristics during straight or turning
flight decelerations if it is not always
possible to produce and to correct roll
and yaw by unreversed use of aileron
and rudder controls, or abnormal noseup pitching occurs.
5. Handling Characteristics at High
Incidence
a. High Incidence Handling
Demonstrations
In lieu of § 25.201, ‘‘Stall
demonstration,’’ the following is
required:
i. Maneuvers to the limit of the
longitudinal control, in nose-up pitch,
must be demonstrated in straight flight
and in 30-degree banked turns with:
1. The high-incidence protection
system operating normally;
2. Initial power conditions of:
a. Power off; and
b. Power necessary to maintain level
flight at 1.5 VSR1, where VSR1 is the
reference stall speed with flaps in
approach position, landing gear
retracted, and maximum landing
weight;
3. None;
4. Flaps, landing gear, and
deceleration devices in any likely
combination of positions not prohibited
by the airplane flight manual (AFM);
5. Representative weights within the
range for which certification is
requested;
6. The most adverse CG for recovery;
and
7. The airplane trimmed for straight
flight at the speed prescribed in section
3(e)(v) of these special conditions.
ii. The following procedures must be
used to show compliance in non-icing
and icing conditions:
1. Starting at a speed sufficiently
above the minimum steady flight speed
to ensure that a steady rate of speed
reduction can be established, apply the
longitudinal control so that the speed
reduction does not exceed 1 knot per
second until the control reaches the
stop.
2. The longitudinal control must be
maintained at the stop until the airplane
has reached a stabilized flight condition
and must then be recovered by normal
recovery techniques.
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3. Maneuvers with increased
deceleration rates:
a. In non-icing conditions, the
requirements must also be met with
increased rates of entry to the incidence
limit, up to the maximum rate
achievable.
b. In icing conditions, with the antiice system working normally, the
requirements must also be met with
increased rates of entry to the incidence
limit, up to three knots per second.
4. Maneuvers with ice accretion prior
to normal operation of the ice protection
system: For flight in icing conditions
before the ice protection system has
been activated and is performing its
intended function, the handling
demonstration requirements identified
in section 5(a)(i) must be satisfied using
the procedures specified in sections
5(a)(ii)(1) and 5(a)(ii)(2) of these special
conditions. The airplane configurations
required to be tested must be in
accordance with the limitations and
procedures for operating the ice
protection system provided in the AFM,
per § 25.21(g)(1), as modified by and
Part II of these special conditions.
b. Characteristics in High Incidence
Maneuvers
In lieu of § 25.203, ‘‘Stall
characteristics,’’ the following apply:
i. Throughout maneuvers with a rate
of deceleration of not more than 1 knot
per second, both in straight flight and in
30-degree banked turns, the airplane’s
characteristics must be as follows:
1. There must not be any abnormal
nose-up pitching;
2. There must not be any
uncommanded nose-down pitching,
which would be indicative of stall.
However, reasonable attitude changes
associated with stabilizing the incidence
at Alpha limit, as the longitudinal
control reaches the stop would be
acceptable;
3. There must not be any
uncommanded lateral or directional
motion, and the pilot must retain good
lateral and directional control by
conventional use of the controls
throughout the maneuver; and
4. The airplane must not exhibit
buffeting of a magnitude and severity
that would act as a deterrent from
completing the maneuver specified in
section 5(a)(i) of these special
conditions.
ii. In maneuvers with increased rates
of deceleration, some degradation of
characteristics is acceptable, associated
with a transient excursion beyond the
stabilized Alpha limit. However, the
airplane must not exhibit dangerous
characteristics or characteristics that
would deter the pilot from holding the
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longitudinal control on the stop for a
period of time appropriate to the
maneuver.
iii. It must always be possible for
flightcrew to reduce incidence by
conventional use of the controls.
iv. The rate at which the airplane can
be maneuvered from trim speeds,
associated with scheduled operating
speeds such as V2 and VREF up to Alpha
limit, must not be unduly damped or be
significantly slower than can be
achieved on conventionally controlled
transport airplanes.
c. Characteristics up to the Maximum
Lift Angle of Attack
In addition to the requirements in
section 5(b) of this special condition,
the following requirements apply:
i. In non-icing conditions, maneuvers
with a rate of deceleration of not more
than 1 knot per second, up to the angle
of attack corresponding to VSR obtained
using sections 3(d) and (e) of this
special condition, must be demonstrated
in straight flight and in 30-degree
banked turns in the following
configurations:
1. The high-incidence protection
system deactivated or adjusted, at the
option of the applicant, to allow higher
incidence than is possible with the
normal production system;
iii. During the maneuvers used to
show compliance with sections 5(c)(i)
and 5(c)(ii) of Part I of these special
conditions, the airplane must not
exhibit dangerous characteristics and it
must always be possible for flightcrew
to reduce angle of attack by
conventional use of the controls. The
pilot must retain good lateral and
directional control, by conventional use
of the controls, throughout the
maneuver.
6. Atmospheric Disturbances
Operation of the high-incidence
protection system must not adversely
affect airplane control during expected
levels of atmospheric disturbances, nor
impede the application of recovery
procedures in case of wind shear. This
must be demonstrated in non-icing and
icing conditions.
7. None
8. Proof of Compliance
Add the following requirement to that
of § 25.21:
(b) The flying qualities will be
evaluated at the most unfavorable CG
position.
9. The Design Must Meet the Following
Modified Requirements
14 CFR section
Change
25.145(a) ..............................
25.145(b)(6) ..........................
25.175(c) and (d) .................
25.1323(d) ............................
‘‘VMIN’’ in lieu of ‘‘stall identification.’’
‘‘VMIN’’ in lieu of ‘‘VSW.’’
‘‘VMIN’’ in lieu of ‘‘VSW.’’
‘‘From 1.23 VSR to VMIN’’ in lieu of ‘‘From 1.23 VSR to the speed at which stall warning begins;’’ and ‘‘speeds
below VMIN’’ in lieu of ‘‘speeds below stall warning speed.’’
Part II: Credit for Robust Envelope
Protection in Icing Conditions
ddrumheller on DSK120RN23PROD with RULES1
2. Automatic-thrust-increase system
inhibited (if applicable);
3. Engines idling;
4. Flaps, landing gear, and
deceleration devices in any likely
combination of positions not prohibited
by the AFM;
5. The most adverse CG for recovery;
and
6. The airplane trimmed for straight
flight at the speed prescribed in section
3(e)(v) of this special condition.
ii. In icing conditions, maneuvers
with a rate of deceleration of not more
than 1 knot per second up to the
maximum angle of attack reached
during maneuvers from section
5(a)(ii)(3)(b) must be demonstrated in
straight flight with:
1. The high-incidence protection
system deactivated or adjusted, at the
option of the applicant, to allow higher
incidence than is possible with the
normal production system;
2. Automatic-thrust-increase system
inhibited (if applicable);
3. Engines idling;
4. Flaps, landing gear, and
deceleration devices in any likely
combination of positions not prohibited
by the AFM;
5. The most adverse CG for recovery;
and
6. The airplane trimmed for straight
flight at the speed prescribed in section
3(e)(v) of this special condition.
1. In lieu of § 25.21(g)(1), the
following applies:
(g) The requirements of this subpart
associated with icing conditions apply
only if certification for flight in icing
conditions is desired. If certification for
flight in icing conditions is desired, the
following requirements also apply (see
AC 25–25):
(1) Each requirement of this subpart,
except §§ 25.121(a), 25.123(c),
25.143(b)(1) and (b)(2), 25.149,
25.201(c)(2), 25.207(c) and (d), and
25.251(b) through (e), must be met in
icing conditions. Compliance must be
shown using the ice accretions defined
in appendix C to part 25, assuming
normal operation of the airplane and its
ice protection system in accordance
with the operating limitations and
operating procedures established by the
VerDate Sep<11>2014
16:41 Mar 08, 2024
Jkt 262001
applicant and provided in the airplane
flight manual.
2. In lieu of § 25.103, ‘‘Stall speed,’’
define the stall speed as provided in
Special Conditions Part I, section 3,
‘‘Minimum Steady Flight Speed and
Reference Stall Speed.’’
3. In lieu of § 25.105(a)(2)(i) to read as
follows:
(2) In icing conditions, if in the
configuration of § 25.121(b) with the
‘‘Takeoff Ice’’ accretion defined in
appendix C to part 25:
(i) The V2 speed scheduled in nonicing conditions does not provide the
maneuvering capability specified in
§ 25.143(h) for the takeoff configuration,
or
4. In lieu of § 25.107(c) and (g), the
following apply, with additional
sections (c′) and (g′):
(c) In non-icing conditions, V2, in
terms of calibrated airspeed, must be
selected by the applicant to provide at
PO 00000
Frm 00010
Fmt 4700
Sfmt 4700
least the gradient of climb required by
§ 25.121(b) but may not be less than—
1. V2MIN;
2. VR plus the speed increment
attained (in accordance with
§ 25.111(c)(2)) before reaching a height
of 35 feet above the takeoff surface; and
3. A speed that provides the
maneuvering capability specified in
§ 25.143(h).
(c′) In icing conditions with the
‘‘Takeoff Ice’’ accretion defined in
appendix C to part 25, V2 may not be
less than—
1. The V2 speed determined in nonicing conditions.
2. A speed that provides the
maneuvering capability specified in
§ 25.143(h).
(g) In non-icing conditions, VFTO, in
terms of calibrated airspeed, must be
selected by the applicant to provide at
least the gradient of climb required by
§ 25.121(c), but may not be less than—
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11MRR1
Federal Register / Vol. 89, No. 48 / Monday, March 11, 2024 / Rules and Regulations
ddrumheller on DSK120RN23PROD with RULES1
1. 1.18 VSR; and
2. A speed that provides the
maneuvering capability specified in
§ 25.143(h).
(g′) In icing conditions with the ‘‘Final
Takeoff Ice’’ accretion defined in
appendix C to part 25, VFTO may not be
less than—
1. The VFTO speed determined in nonicing conditions.
2. A speed that provides the
maneuvering capability specified in
§ 25.143(h).
5. In lieu of §§ 25.121(b)(2)(ii)(A),
25.121(c)(2)(ii)(A), and 25.121(d)(2)(ii),
the following apply:
§ 25.121 Climb: One-Engine
Inoperative
(b) Takeoff; landing gear retracted. In
the takeoff configuration existing at the
point of the flight path at which the
landing gear is fully retracted, and in
the configuration used in § 25.111, but
without ground effect,
*
*
*
*
*
2. The requirements of subparagraph
(b)(1) of this section must be met:
*
*
*
*
*
(ii) In icing conditions with the
‘‘Takeoff Ice’’ accretion defined in
appendix C of part 25, if in the
configuration of § 25.121(b) with the
‘‘Takeoff Ice’’ accretion:
(A) The V2 speed scheduled in nonicing conditions does not provide the
maneuvering capability specified in
§ 25.143(h) for the takeoff configuration;
or
(c) Final takeoff. In the en route
configuration at the end of the takeoff
path determined in accordance with
§ 25.111:
*
*
*
*
*
2. The requirements of subparagraph
(c)(1) of this section must be met:
*
*
*
*
*
(ii) In icing conditions with the ‘‘Final
Takeoff Ice’’ accretion defined in
appendix C of part 25, if:
(A) The VFTO speed scheduled in nonicing conditions does not provide the
maneuvering capability specified in
§ 25.143(h) for the en route
configuration; or
(d) Approach. In a configuration
corresponding to the normal all-engines
operating procedure in which VSR for
this configuration does not exceed 110
percent of the VSR for the related allengines-operating landing configuration:
*
*
*
*
*
2. The requirements of sub-paragraph
(d)(1) of this section must be met:
*
*
*
*
*
(ii) In icing conditions with the
‘‘Approach Ice’’ accretion defined in
appendix C to part 25, in a configuration
VerDate Sep<11>2014
16:41 Mar 08, 2024
Jkt 262001
corresponding to the normal all-enginesoperating procedure in which VMIN1g for
this configuration does not exceed
110% of the VMIN1g for the related all
engines-operating landing configuration
in icing, with a climb speed established
with normal landing procedures, but not
more than 1.4 VSR (VSR determined in
non-icing conditions).
6. In lieu of § 25.123(b)(2)(i), the
following applies:
§ 25.123
En Route Flight Paths
17281
demonstrated in flight with the ice
accretion defined in part II(e) of
appendix C to part 25 that:
(i) The airplane is controllable in a
pull-up maneuver up to 1.5 g load factor
or lower if limited by angle of attack
protection; and
(ii) There is no reversal of pitch
control force during a pushover
maneuver down to 0.5 g load factor.
9. In lieu of § 25.207, ‘‘Stall warning,’’
to read as the requirements defined in
Part I of these special conditions.
(b) The one-engine-inoperative net
flight path data must represent the
actual climb performance diminished by
a gradient of climb of 1.1 percent for
two-engine airplanes, 1.4 percent for
three-engine airplanes, and 1.6 percent
for four-engine airplanes.
*
*
*
*
*
2. In icing conditions with the ‘‘En
route Ice’’ accretion defined in appendix
C to part 25 if:
(i) The minimum en route speed
scheduled in non-icing conditions does
not provide the maneuvering capability
specified in § 25.143(h) for the en route
configuration, or
7. In lieu of § 25.125(b)(2)(ii)(B) and
§ 25.125(b)(2)(ii)(C), the following
applies:
Issued in Kansas City, Missouri, on March
5, 2024.
James David Foltz,
Manager, Technical Policy Branch, Policy and
Standards Division, Aircraft Certification
Service.
§ 25.125
Amendment of Class D and Class E
Airspace and Revocation of Class E
Airspace; Clarksburg, WV
Landing
(b) In determining the distance in (a):
*
*
*
*
2. A stabilized approach, with a
calibrated airspeed of not less than
VREF, must be maintained down to the
50-foot height.
*
*
*
*
*
(ii) In icing conditions, VREF may not
be less than:
(A) The speed determined in subparagraph (b)(2)(i) of this section;
(B) A speed that provides the
maneuvering capability specified in
§ 25.143(h) with the ‘‘Landing Ice’’
accretion defined in appendix C to part
25.
8. In lieu of § 25.143(j), the following
applies:
*
§ 25.143
General
(j) For flight in icing conditions before
the ice protection system has been
activated and is performing its intended
function the following requirements
apply:
(1) If activating the ice protection
system depends on the pilot seeing a
specified ice accretion on a reference
surface (not just the first indication of
icing), the requirements of § 25.143
apply with the ice accretion defined in
part II(e) of appendix C to part 25.
(2) For other means of activating the
ice protection system, it must be
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[FR Doc. 2024–05043 Filed 3–8–24; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 71
[Docket No. FAA–2023–2362; Airspace
Docket No. 23–AEA–25]
RIN 2120–AA66
Federal Aviation
Administration (FAA), DOT.
ACTION: Final rule.
AGENCY:
This action amends the Class
D and Class E airspace and revokes
Class E airspace at Clarksburg, WV. This
action is the result of a biennial airspace
review. This action brings the airspace
into compliance with FAA orders to
support instrument flight rule (IFR)
operations.
DATES: Effective 0901 UTC, May 16,
2024. The Director of the Federal
Register approves this incorporation by
reference action under 1 CFR part 51,
subject to the annual revision of FAA
Order JO 7400.11 and publication of
conforming amendments.
ADDRESSES: A copy of the Notice of
Proposed Rulemaking (NPRM), all
comments received, this final rule, and
all background material may be viewed
online at www.regulations.gov using the
FAA Docket number. Electronic
retrieval help and guidelines are
available on the website. It is available
24 hours each day, 365 days each year.
FAA Order JO 7400.11H, Airspace
Designations and Reporting Points, and
subsequent amendments can be viewed
online at www.faa.gov/air_traffic/
SUMMARY:
E:\FR\FM\11MRR1.SGM
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]]>Agencies
[Federal Register Volume 89, Number 48 (Monday, March 11, 2024)]
[Rules and Regulations]
[Pages 17276-17281]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-05043]
=======================================================================
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2023-2441; Special Conditions No. 25-853-SC]
Special Conditions: Gulfstream Aerospace Corporation Model GVIII-
G700 and GVIII-G800 Airplanes; Flight Envelope Protection: High-
Incidence Protection System (Non-Icing and Icing Conditions)
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions; request for comments.
-----------------------------------------------------------------------
SUMMARY: These special conditions are issued for the Gulfstream
Aerospace Corporation (Gulfstream) Model GVIII-G700 and GVIII-G800
series airplanes. These airplanes 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 a high-incidence protection system that limits the angle of
attack at which the airplane can be flown during normal low speed
operation. 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 date: This action is effective on Gulfstream on March 11,
2024.
Comments due date: Send comments on or before April 25, 2024.
ADDRESSES: Send comments identified by Docket No. FAA-2023-2441 using
any of the following methods:
Federal eRegulations Portal: Go to 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.
Docket: Background documents or comments received may be
read at 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 Unit, AIR-621A, Technical Policy Branch, Policy and
Standards Division, Aircraft Certification Service, Federal Aviation
Administration, 1801 S Airport Rd., Wichita, KS 67209-2190; telephone
405-666-1050; email [email protected].
SUPPLEMENTARY INFORMATION: The anticipated delivery date for these
airplane models is imminent. Therefore, the FAA finds, pursuant to 14
CFR 11.38(a), that prior notice and comments would significantly delay
delivery of the affected aircraft, so notice and comment prior to this
publication are impracticable. Therefore, the FAA is issuing these
special conditions as final, request for comments.
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 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
[[Page 17277]]
conditions. Send submissions containing CBI to the individual listed in
the FOR FURTHER INFORMATION CONTACT section above. Comments the FAA
receives, which are not specifically designated as CBI, will be placed
in the public docket for these special conditions.
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 and will consider comments filed late if it is possible to do
so without incurring delay. The FAA may change these special conditions
based on the comments received.
Background
On December 31, 2019, Gulfstream applied for an amendment to Type
Certificate No. T00015AT to include the new Model GVIII-G700 and GVIII-
G800 series airplanes. These airplanes, which are derivatives of the
Model GVI currently approved under Type Certificate No. T00015AT, are
twin-engine, transport-category airplanes, with seating for 19
passengers, and a maximum take-off weight of 107,600 (GVIII-G700)
pounds and 105,600 pounds (GVIII-G800).
Type Certification Basis
Under the provisions of title 14, Code of Federal Regulations (14
CFR) 21.101, Gulfstream must show that the Model GVIII-G700 and GVIII-
G800 series airplanes meet the applicable provisions of the regulations
listed in Type Certificate No. T00015AT, or the applicable regulations
in effect on the date of application for the change, except for earlier
amendments as agreed upon by the FAA.
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 Gulfstream Model GVIII-G700 and
GVIII-G800 series airplanes 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, or should any other model already included on
the same type certificate be modified to incorporate 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 Gulfstream Model GVIII-G700 and GVIII-G800 series
airplanes must comply with the 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 14 CFR 11.38, and they become part of the type
certification basis under Sec. 21.101.
Novel or Unusual Design Features
The Gulfstream Model GVIII-G700 and GVIII-G800 airplanes will
incorporate the following novel or unusual design feature:
A high-incidence protection system that limits the angle of attack
at which the airplane can be flown during normal low speed operation,
prohibits the airplane from stalling, and cannot be overridden by the
flightcrew. The application of this angle of attack limit influences
the stall speed determination, stall characteristics, stall warning
demonstration, and the longitudinal handling characteristics of the
airplane. Existing airworthiness regulations do not contain adequate
standards to address this feature.
Discussion
The high-incidence protection system prevents the airplane from
stalling at low speeds and, therefore, a stall warning system is not
needed during normal flight conditions. However, during failures, which
are not shown to be extremely improbable, the requirements of
Sec. Sec. 25.203 and 25.207 apply, although slightly modified by these
conditions. If there are failures of the high-incidence protection
system that are not shown to be extremely improbable, the flight
characteristics at the angle of attack for CLMAX must be
suitable in the traditional sense, and stall warning must be provided
in a conventional manner.
Part I of the special conditions is in lieu of Sec. Sec. 25.21(b),
25.103, 25.145(a), 25.145(b)(6), 25.175(c) and (d), 25.201, 25.203,
25.207, and 25.1323(d). Part II is in lieu of Sec. Sec. 25.21(g)(1),
25.105(a)(2)(i), 25.107(c) and (g), 25.121(b)(2)(ii)(A),
25.121(c)(2)(ii)(A), 25.121(d)(2)(ii), 25.123(b)(2)(i),
25.125(b)(2)(ii)(B), and 25.143(j).
These special conditions are different from previously issued
special conditions on this topic. Previously used verbiage was updated
to reflect language recommended in the Aviation Rulemaking Advisory
Committee (ARAC) Flight Test Harmonization Working Group (FTHWG) Phase
2 report. This language more accurately describes the actions require
and formulas to be used to obtain the required result. In certain
parts, the ARAC FTHWG language was adapted to further reflect specific
Gulfstream design features such as flight envelope protection
functions.
These special conditions address this novel or unusual design
feature on the Gulfstream Model GVIII-G700 and GVIII-G800 series
airplanes and 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
Gulfstream Model GVIII-G700 and GVIII-G800 series airplanes. Should
Gulfstream apply at a later date for a change to the type certificate
to include another model that incorporates the same novel or unusual
design feature, or should any other model already included on the same
type certificate be modified to incorporate the same novel or unusual
design feature, these special conditions would apply to the other model
as well.
Conclusion
This action affects only certain novel or unusual design features
on Gulfstream Model GVIII-G700 and GVIII-G800 series of airplanes. 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, and
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 Gulfstream Model GVIII-G700 and GVIII-
G800 series airplanes.
[[Page 17278]]
Part I: Stall Protection and Scheduled Operating Speeds
In the following sections, ``in icing conditions,'' means with ice
accretions (relative to the relevant flight phase) as defined in
appendix C to part 25, at amendment 25-121.
1. Definitions
These special conditions use terminology that does not appear in 14
CFR part 25. For the purpose of these special conditions, the following
terms describe certain aspects of this novel or unusual design feature:
High-Incidence Protection System
A system that operates directly and automatically on the airplane's
flight controls to limit the maximum angle of attack that can be
attained to a value below that at which an aerodynamic stall would
occur.
Alpha Limit
The maximum angle of attack at which an airplane stabilizes with
the high-incidence protection system operating and the longitudinal
control held on its aft stop.
VMIN
The minimum steady flight speed in the airplane's configuration
under consideration with the high-incidence protection system
operating. See Part I, Section 3, ``Minimum Steady Flight Speed and
Reference Stall Speed,'' of these special conditions.
VMIN1g
VMIN corrected to 1g acceleration of gravity conditions.
See Part I, Section 3, ``Minimum Steady Flight Speed and Reference
Stall Speed,'' of these special conditions. This is the minimum
calibrated airspeed at which the airplane can develop a lift force
normal to the flight path and equal to its weight when at an angle of
attack not greater than that determined for VMIN.
2. Capability and Reliability of the High-Incidence Protection System
The applicant must establish the capability and reliability of the
high-incidence protection system. The applicant may establish this
capability and reliability by flight testing, simulation, or analysis
as appropriate. The capability and reliability required are:
a. It must not be possible to encounter a stall during the pilot-
induced maneuvers required by Part I, section 5(a), ``High Incidence
Handling Demonstrations,'' and the handling characteristics must be
acceptable as required by Part I, section 5(b), ``Characteristics in
High Incidence Maneuvers'' of these special conditions;
b. The airplane must be protected against stalling due to the
effects of wind shears and gusts at low speeds as required by Section
6, ``Atmospheric Disturbances'' of these special conditions;
c. The ability of the high-incidence protection system to
accommodate any reduction in stalling incidence must be verified in
icing conditions;
d. The high-incidence protection system must be provided in each
abnormal configuration of the high lift devices that is likely to be
used in flight following system failures; and
e. The reliability of the system and the effects of failures must
be acceptable in accordance with Sec. 25.1309.
3. Minimum Steady Flight Speed and Reference Stall Speed
In lieu of Sec. 25.103, ``Stall speed,'' the following applies:
a. The minimum steady flight speed, VMIN, is the final,
stabilized, calibrated airspeed obtained when an airplane is
decelerated until the longitudinal control is on its stop in such a way
that the entry rate does not exceed 1 knot per second.
b. The minimum steady flight speed, VMIN, must be
determined in icing and non-icing conditions with:
i. The high-incidence protection system operating normally;
ii. Idle thrust and automatic thrust system (if applicable)
inhibited;
iii. All combinations of flap settings and landing gear positions
for which VMIN is required to be determined;
iv. The weight used when the reference stall speed, VSR,
is used as a factor to determine compliance with a required performance
standard;
v. The most unfavorable center of gravity (CG) allowable; and
vi. The airplane trimmed for straight flight at a speed selected by
the applicant, but not less than 1.13 VSR and not greater
than 1.3 VSR.
c. The 1g minimum steady flight speed, VMIN1g, is the
minimum calibrated airspeed at which an airplane can develop a lift
force (normal to the flight path) equal to its weight, while at an
angle of attack not greater than that at which the minimum steady
flight speed referenced in section 3(a) of this special condition is
determined. These minimum calibrated airspeeds must be determined for
both icing and non-icing conditions.
d. The reference stall speed, VSR, is a calibrated
airspeed defined by the applicant. VSR may not be less than
a 1g stall speed. VSR must be determined in non-icing
conditions and expressed as:
[GRAPHIC] [TIFF OMITTED] TR11MR24.000
Where:
VCLMAX = calibrated airspeed obtained when the load
factor-corrected lift coefficient
[GRAPHIC] [TIFF OMITTED] TR11MR24.001
is first a maximum during the maneuver prescribed in section
3(e)(vii) of this special condition.
nZW = Load factor normal to the flight path at
VCLMAX
W = Airplane gross weight;
S = Aerodynamic reference wing area; and
q = Dynamic pressure.
e. VCLMAX is determined in non-icing conditions with:
i. Engines idling, or, if that resultant thrust causes an
appreciable decrease in stall speed, not more than zero thrust at the
stall speed;
ii. The airplane in other respects (such as flaps and landing gear)
in the condition existing in the test or performance standard in which
VSR is being used;
iii. The weight used when VSR is being used as a factor
to determine compliance with a required performance standard;
iv. The CG position that results in the highest value of the
reference stall speed;
v. The airplane trimmed for straight flight at a speed selected by
the applicant, but not less than 1.13 VSR and not greater
than 1.3 VSR;
vi. The high-incidence protection system adjusted, at the option of
the applicant, to allow high incidence than is possible with the normal
production system; and
vii. Starting from the stabilized trim condition, with an
application of the longitudinal control to decelerate the airplane so
that the speed reduction does not exceed 1 knot per second.
4. Stall Warning
In lieu of Sec. 25.207, the following apply:
a. Normal Operation
If the design meets all conditions of Part I, section 2 of these
special conditions, then the airplane need not provide stall warning
during normal operation. The conditions of Part I, section 2 provide a
level of safety equal to the intent of Sec. 25.207, ``Stall warning,''
so the provision of an additional, unique warning device for normal
operations is not required.
b. High-Incidence Protection System Failure
For any failures of the high-incidence protection system that the
applicant
[[Page 17279]]
cannot show to be extremely improbable, and that result in the
capability of the system no longer satisfying any part of sections
2(a), (b), and (c) of Part I of these special conditions: The design
must provide stall warning that protects against encountering
unacceptable characteristics and against encountering stall.
i. This stall warning, with the flaps and landing gear in any
normal position, must be clear and distinctive to the pilot, and must
meet the requirements specified in sections 4(b)(iv) and 4(b)(v) of
Part I of these special conditions.
ii. The design must also provide this stall warning in each
abnormal configuration of the high lift devices that is likely to be
used in flight following system failures.
iii. The design may furnish this stall warning either through the
inherent aerodynamic qualities of the airplane or by a device that will
provide clearly distinguishable indications to the flightcrew under all
expected conditions of flight. However, a visual stall warning device
that requires the attention of the flightcrew within the flight deck is
not acceptable by itself. If a warning device is used, it must provide
a warning in each of the airplane configurations prescribed in section
4(b)(i), above, and for the conditions prescribed in sections 4(b)(iv)
and 4(b)(v) of part I of these special conditions.
iv. In non-icing conditions, the stall warning must provide
sufficient margin to prevent encountering unacceptable characteristics
and encountering stall in the following conditions:
1. In power-off straight deceleration not exceeding 1 knot per
second to a speed of 5 knots or 5 percent calibrated airspeed (CAS),
whichever is greater, below the warning onset; and
2. In turning flight, stall deceleration at entry rates up to 3
knots per second when recovery is initiated not less than 1 second
after the warning onset.
v. In icing conditions, the stall warning must provide sufficient
margin to prevent encountering unacceptable characteristics and
encountering stall in power-off straight and turning flight
decelerations not exceeding 1 knot per second, when the pilot starts a
recovery maneuver not less than three seconds after the onset of stall
warning.
vi. An airplane is considered stalled when the behavior of the
airplane gives the pilot a clear, distinctive, and acceptable
indication that the airplane is stalled. Acceptable indications of a
stall, occurring either individually or in combination, are:
1. A nose-down pitch that cannot be readily arrested;
2. Buffeting of a magnitude and severity that is strong and thereby
an effective deterrent to further speed reduction; or
3. The pitch control reaches the aft stop, and no further increase
in pitch attitude occurs when the control is held full aft for a short
time before recovery is initiated.
vii. An airplane exhibits unacceptable characteristics during
straight or turning flight decelerations if it is not always possible
to produce and to correct roll and yaw by unreversed use of aileron and
rudder controls, or abnormal nose-up pitching occurs.
5. Handling Characteristics at High Incidence
a. High Incidence Handling Demonstrations
In lieu of Sec. 25.201, ``Stall demonstration,'' the following is
required:
i. Maneuvers to the limit of the longitudinal control, in nose-up
pitch, must be demonstrated in straight flight and in 30-degree banked
turns with:
1. The high-incidence protection system operating normally;
2. Initial power conditions of:
a. Power off; and
b. Power necessary to maintain level flight at 1.5 VSR1,
where VSR1 is the reference stall speed with flaps in
approach position, landing gear retracted, and maximum landing weight;
3. None;
4. Flaps, landing gear, and deceleration devices in any likely
combination of positions not prohibited by the airplane flight manual
(AFM);
5. Representative weights within the range for which certification
is requested;
6. The most adverse CG for recovery; and
7. The airplane trimmed for straight flight at the speed prescribed
in section 3(e)(v) of these special conditions.
ii. The following procedures must be used to show compliance in
non-icing and icing conditions:
1. Starting at a speed sufficiently above the minimum steady flight
speed to ensure that a steady rate of speed reduction can be
established, apply the longitudinal control so that the speed reduction
does not exceed 1 knot per second until the control reaches the stop.
2. The longitudinal control must be maintained at the stop until
the airplane has reached a stabilized flight condition and must then be
recovered by normal recovery techniques.
3. Maneuvers with increased deceleration rates:
a. In non-icing conditions, the requirements must also be met with
increased rates of entry to the incidence limit, up to the maximum rate
achievable.
b. In icing conditions, with the anti-ice system working normally,
the requirements must also be met with increased rates of entry to the
incidence limit, up to three knots per second.
4. Maneuvers with ice accretion prior to normal operation of the
ice protection system: For flight in icing conditions before the ice
protection system has been activated and is performing its intended
function, the handling demonstration requirements identified in section
5(a)(i) must be satisfied using the procedures specified in sections
5(a)(ii)(1) and 5(a)(ii)(2) of these special conditions. The airplane
configurations required to be tested must be in accordance with the
limitations and procedures for operating the ice protection system
provided in the AFM, per Sec. 25.21(g)(1), as modified by and Part II
of these special conditions.
b. Characteristics in High Incidence Maneuvers
In lieu of Sec. 25.203, ``Stall characteristics,'' the following
apply:
i. Throughout maneuvers with a rate of deceleration of not more
than 1 knot per second, both in straight flight and in 30-degree banked
turns, the airplane's characteristics must be as follows:
1. There must not be any abnormal nose-up pitching;
2. There must not be any uncommanded nose-down pitching, which
would be indicative of stall. However, reasonable attitude changes
associated with stabilizing the incidence at Alpha limit, as the
longitudinal control reaches the stop would be acceptable;
3. There must not be any uncommanded lateral or directional motion,
and the pilot must retain good lateral and directional control by
conventional use of the controls throughout the maneuver; and
4. The airplane must not exhibit buffeting of a magnitude and
severity that would act as a deterrent from completing the maneuver
specified in section 5(a)(i) of these special conditions.
ii. In maneuvers with increased rates of deceleration, some
degradation of characteristics is acceptable, associated with a
transient excursion beyond the stabilized Alpha limit. However, the
airplane must not exhibit dangerous characteristics or characteristics
that would deter the pilot from holding the
[[Page 17280]]
longitudinal control on the stop for a period of time appropriate to
the maneuver.
iii. It must always be possible for flightcrew to reduce incidence
by conventional use of the controls.
iv. The rate at which the airplane can be maneuvered from trim
speeds, associated with scheduled operating speeds such as
V2 and VREF up to Alpha limit, must not be unduly
damped or be significantly slower than can be achieved on
conventionally controlled transport airplanes.
c. Characteristics up to the Maximum Lift Angle of Attack
In addition to the requirements in section 5(b) of this special
condition, the following requirements apply:
i. In non-icing conditions, maneuvers with a rate of deceleration
of not more than 1 knot per second, up to the angle of attack
corresponding to VSR obtained using sections 3(d) and (e) of
this special condition, must be demonstrated in straight flight and in
30-degree banked turns in the following configurations:
1. The high-incidence protection system deactivated or adjusted, at
the option of the applicant, to allow higher incidence than is possible
with the normal production system;
2. Automatic-thrust-increase system inhibited (if applicable);
3. Engines idling;
4. Flaps, landing gear, and deceleration devices in any likely
combination of positions not prohibited by the AFM;
5. The most adverse CG for recovery; and
6. The airplane trimmed for straight flight at the speed prescribed
in section 3(e)(v) of this special condition.
ii. In icing conditions, maneuvers with a rate of deceleration of
not more than 1 knot per second up to the maximum angle of attack
reached during maneuvers from section 5(a)(ii)(3)(b) must be
demonstrated in straight flight with:
1. The high-incidence protection system deactivated or adjusted, at
the option of the applicant, to allow higher incidence than is possible
with the normal production system;
2. Automatic-thrust-increase system inhibited (if applicable);
3. Engines idling;
4. Flaps, landing gear, and deceleration devices in any likely
combination of positions not prohibited by the AFM;
5. The most adverse CG for recovery; and
6. The airplane trimmed for straight flight at the speed prescribed
in section 3(e)(v) of this special condition.
iii. During the maneuvers used to show compliance with sections
5(c)(i) and 5(c)(ii) of Part I of these special conditions, the
airplane must not exhibit dangerous characteristics and it must always
be possible for flightcrew to reduce angle of attack by conventional
use of the controls. The pilot must retain good lateral and directional
control, by conventional use of the controls, throughout the maneuver.
6. Atmospheric Disturbances
Operation of the high-incidence protection system must not
adversely affect airplane control during expected levels of atmospheric
disturbances, nor impede the application of recovery procedures in case
of wind shear. This must be demonstrated in non-icing and icing
conditions.
7. None
8. Proof of Compliance
Add the following requirement to that of Sec. 25.21:
(b) The flying qualities will be evaluated at the most unfavorable
CG position.
9. The Design Must Meet the Following Modified Requirements
------------------------------------------------------------------------
14 CFR section Change
------------------------------------------------------------------------
25.145(a).................... ``VMIN'' in lieu of ``stall
identification.''
25.145(b)(6)................. ``VMIN'' in lieu of ``VSW.''
25.175(c) and (d)............ ``VMIN'' in lieu of ``VSW.''
25.1323(d)................... ``From 1.23 VSR to VMIN'' in lieu of
``From 1.23 VSR to the speed at which
stall warning begins;'' and ``speeds
below VMIN'' in lieu of ``speeds below
stall warning speed.''
------------------------------------------------------------------------
Part II: Credit for Robust Envelope Protection in Icing Conditions
1. In lieu of Sec. 25.21(g)(1), the following applies:
(g) The requirements of this subpart associated with icing
conditions apply only if certification for flight in icing conditions
is desired. If certification for flight in icing conditions is desired,
the following requirements also apply (see AC 25-25):
(1) Each requirement of this subpart, except Sec. Sec. 25.121(a),
25.123(c), 25.143(b)(1) and (b)(2), 25.149, 25.201(c)(2), 25.207(c) and
(d), and 25.251(b) through (e), must be met in icing conditions.
Compliance must be shown using the ice accretions defined in appendix C
to part 25, assuming normal operation of the airplane and its ice
protection system in accordance with the operating limitations and
operating procedures established by the applicant and provided in the
airplane flight manual.
2. In lieu of Sec. 25.103, ``Stall speed,'' define the stall speed
as provided in Special Conditions Part I, section 3, ``Minimum Steady
Flight Speed and Reference Stall Speed.''
3. In lieu of Sec. 25.105(a)(2)(i) to read as follows:
(2) In icing conditions, if in the configuration of Sec. 25.121(b)
with the ``Takeoff Ice'' accretion defined in appendix C to part 25:
(i) The V2 speed scheduled in non-icing conditions does
not provide the maneuvering capability specified in Sec. 25.143(h) for
the takeoff configuration, or
4. In lieu of Sec. 25.107(c) and (g), the following apply, with
additional sections (c') and (g'):
(c) In non-icing conditions, V2, in terms of calibrated
airspeed, must be selected by the applicant to provide at least the
gradient of climb required by Sec. 25.121(b) but may not be less
than--
1. V2MIN;
2. VR plus the speed increment attained (in accordance
with Sec. 25.111(c)(2)) before reaching a height of 35 feet above the
takeoff surface; and
3. A speed that provides the maneuvering capability specified in
Sec. 25.143(h).
(c') In icing conditions with the ``Takeoff Ice'' accretion defined
in appendix C to part 25, V2 may not be less than--
1. The V2 speed determined in non-icing conditions.
2. A speed that provides the maneuvering capability specified in
Sec. 25.143(h).
(g) In non-icing conditions, VFTO, in terms of
calibrated airspeed, must be selected by the applicant to provide at
least the gradient of climb required by Sec. 25.121(c), but may not be
less than--
[[Page 17281]]
1. 1.18 VSR; and
2. A speed that provides the maneuvering capability specified in
Sec. 25.143(h).
(g') In icing conditions with the ``Final Takeoff Ice'' accretion
defined in appendix C to part 25, VFTO may not be less
than--
1. The VFTO speed determined in non-icing conditions.
2. A speed that provides the maneuvering capability specified in
Sec. 25.143(h).
5. In lieu of Sec. Sec. 25.121(b)(2)(ii)(A), 25.121(c)(2)(ii)(A),
and 25.121(d)(2)(ii), the following apply:
Sec. 25.121 Climb: One-Engine Inoperative
(b) Takeoff; landing gear retracted. In the takeoff configuration
existing at the point of the flight path at which the landing gear is
fully retracted, and in the configuration used in Sec. 25.111, but
without ground effect,
* * * * *
2. The requirements of subparagraph (b)(1) of this section must be
met:
* * * * *
(ii) In icing conditions with the ``Takeoff Ice'' accretion defined
in appendix C of part 25, if in the configuration of Sec. 25.121(b)
with the ``Takeoff Ice'' accretion:
(A) The V2 speed scheduled in non-icing conditions does
not provide the maneuvering capability specified in Sec. 25.143(h) for
the takeoff configuration; or
(c) Final takeoff. In the en route configuration at the end of the
takeoff path determined in accordance with Sec. 25.111:
* * * * *
2. The requirements of subparagraph (c)(1) of this section must be
met:
* * * * *
(ii) In icing conditions with the ``Final Takeoff Ice'' accretion
defined in appendix C of part 25, if:
(A) The VFTO speed scheduled in non-icing conditions
does not provide the maneuvering capability specified in Sec.
25.143(h) for the en route configuration; or
(d) Approach. In a configuration corresponding to the normal all-
engines operating procedure in which VSR for this configuration does
not exceed 110 percent of the VSR for the related all-engines-operating
landing configuration:
* * * * *
2. The requirements of sub-paragraph (d)(1) of this section must be
met:
* * * * *
(ii) In icing conditions with the ``Approach Ice'' accretion
defined in appendix C to part 25, in a configuration corresponding to
the normal all-engines-operating procedure in which VMIN1g
for this configuration does not exceed 110% of the VMIN1g
for the related all engines-operating landing configuration in icing,
with a climb speed established with normal landing procedures, but not
more than 1.4 VSR (VSR determined in non-icing
conditions).
6. In lieu of Sec. 25.123(b)(2)(i), the following applies:
Sec. 25.123 En Route Flight Paths
(b) The one-engine-inoperative net flight path data must represent
the actual climb performance diminished by a gradient of climb of 1.1
percent for two-engine airplanes, 1.4 percent for three-engine
airplanes, and 1.6 percent for four-engine airplanes.
* * * * *
2. In icing conditions with the ``En route Ice'' accretion defined
in appendix C to part 25 if:
(i) The minimum en route speed scheduled in non-icing conditions
does not provide the maneuvering capability specified in Sec.
25.143(h) for the en route configuration, or
7. In lieu of Sec. 25.125(b)(2)(ii)(B) and Sec.
25.125(b)(2)(ii)(C), the following applies:
Sec. 25.125 Landing
(b) In determining the distance in (a):
* * * * *
2. A stabilized approach, with a calibrated airspeed of not less
than VREF, must be maintained down to the 50-foot height.
* * * * *
(ii) In icing conditions, VREF may not be less than:
(A) The speed determined in sub-paragraph (b)(2)(i) of this
section;
(B) A speed that provides the maneuvering capability specified in
Sec. 25.143(h) with the ``Landing Ice'' accretion defined in appendix
C to part 25.
8. In lieu of Sec. 25.143(j), the following applies:
Sec. 25.143 General
(j) For flight in icing conditions before the ice protection system
has been activated and is performing its intended function the
following requirements apply:
(1) If activating the ice protection system depends on the pilot
seeing a specified ice accretion on a reference surface (not just the
first indication of icing), the requirements of Sec. 25.143 apply with
the ice accretion defined in part II(e) of appendix C to part 25.
(2) For other means of activating the ice protection system, it
must be demonstrated in flight with the ice accretion defined in part
II(e) of appendix C to part 25 that:
(i) The airplane is controllable in a pull-up maneuver up to 1.5 g
load factor or lower if limited by angle of attack protection; and
(ii) There is no reversal of pitch control force during a pushover
maneuver down to 0.5 g load factor.
9. In lieu of Sec. 25.207, ``Stall warning,'' to read as the
requirements defined in Part I of these special conditions.
Issued in Kansas City, Missouri, on March 5, 2024.
James David Foltz,
Manager, Technical Policy Branch, Policy and Standards Division,
Aircraft Certification Service.
[FR Doc. 2024-05043 Filed 3-8-24; 8:45 am]
BILLING CODE 4910-13-P
