Special Conditions: Dassault Aviation Model Falcon 6X Airplane; Flight Envelope Protection, Icing and Non-Icing Conditions; High-Incidence Protection, 32951-32956 [2023-10971]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 88, Number 99 (Tuesday, May 23, 2023)]
[Rules and Regulations]
[Pages 32951-32956]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-10971]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2021-0629; Special Conditions No. 25-803-SC]


Special Conditions: Dassault Aviation Model Falcon 6X Airplane; 
Flight Envelope Protection, Icing and Non-Icing Conditions; High-
Incidence Protection

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for the Dassault Aviation 
(Dassault) Model Falcon 6X airplane. This airplane will have novel or 
unusual design features associated with flight-envelope protections, in 
icing and non-icing conditions, that use high-incidence protection to 
automatically advance throttles when the airplane angle of attack (AoA) 
reaches a predetermined value. 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 May 23, 2023. Send 
comments on or before July 7, 2023.

ADDRESSES: Send comments identified by Docket No. FAA-2021-0629 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

[[Page 32952]]

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 these 
special conditions.
    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 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 
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 Aviation 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:
    A high-incidence protection system that replaces the stall warning 
system during normal operating conditions, prohibits the airplane from 
stalling, limits the angle of attack at which the airplane can be flown 
during normal low speed operation, and cannot be overridden by the 
flight crew. The application of this angle-of-attack limit impacts the 
stall speed determination, the stall characteristics and stall-warning 
demonstration, and the longitudinal handling characteristics. The 
current airworthiness standards do not contain adequate safety 
standards for the unique features of the high-incidence protection 
system.

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 failure 
conditions, which are not shown to be extremely improbable, the 
requirements of Sec. Sec.  25.203 and 25.207 apply, although slightly 
modified. If there are failures not shown to be extremely improbable, 
the flight characteristics at the AoA for CLmax must be 
suitable in the traditional sense, and stall warning must be provided 
in a conventional manner.
    These special conditions address this novel or unusual design 
feature on the Dassault Model Falcon 6X 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 
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 certain novel or unusual design features 
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 Dassault Aviation Model Falcon 6X 
airplanes.

Special Conditions Part I: Stall Protection and Scheduled Operating 
Speeds

Foreword

    In the following paragraphs, ``in icing conditions'' means with the 
ice

[[Page 32953]]

accretions (relative to the relevant flight phase) as defined in 14 CFR 
part 25, Amendment 121, appendix C.

(a) Definitions

    These special conditions address novel or unusual design features 
of the Dassault Model Falcon 6X airplane and 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 these novel 
or unusual design feature:
(1) High-Incidence Protection System
    A system that operates directly and automatically on the airplane's 
flight controls to limit the maximum angle of attack (AoA) that can be 
attained to a value below that at which an aerodynamic stall would 
occur.
(2) Alpha-Limit
    The maximum AoA at which the airplane stabilizes with the high-
incidence protection system operating and the longitudinal control held 
on its aft stop.
(3) Vmin
    The minimum steady flight speed in the airplane configuration under 
consideration with the high-incidence protection system operating. See 
section (c) of these special conditions.
(4) Vmin1g
    Vmin corrected to 1-g conditions. See section (c)(3). of 
these special conditions. It is the minimum calibrated airspeed at 
which the airplane can develop a lift force normal to the flight path 
equal to its weight, while at an AoA not greater than that determined 
for Vmin.

(b) 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 test, simulation, or analysis as 
appropriate. The capability and reliability required are:
    (1) It must not be possible during pilot-induced maneuvers to 
encounter a stall and handling characteristics must be acceptable, as 
required by section (e) of these Special Conditions.
    (2) The airplane must be protected against stalling due to the 
effects of wind-shears and gusts at low speeds as required by section 
(f) of these Special Conditions.
    (3) The ability of the high-incidence protection system to 
accommodate any reduction in stalling incidence must be verified in 
icing conditions.
    (4) 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.
    (5) The reliability of the system and the effects of failures must 
be acceptable in accordance with Sec.  25.1309.

(c) Minimum Steady Flight Speed and Reference Stall Speed

    In lieu of Sec.  25.103, the following requirements apply:
    (1) The minimum steady flight speed, Vmin, is the final, 
stabilized, calibrated airspeed obtained when the 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.
    (2) 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 flaps setting and landing gear position 
for which Vmin is required to be determined;
    (iv) The weight used when reference stall speed, VSR, is 
being used as a factor to determine compliance with a required 
performance standard;
    (v) The most unfavorable center of gravity allowable; and
    (vi) The airplane trimmed for straight flight at a speed achievable 
by the automatic trim system.
    (3) The 1-g minimum steady-flight speed, Vmin1g, is the 
minimum calibrated airspeed at which the 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 of section (c)(1) was determined. It must be determined in 
icing and non-icing conditions.
    (4) 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] TR23MY23.017

Where:

Calibrated airspeed obtained when the load factor-corrected lift 
coefficient
[GRAPHIC] [TIFF OMITTED] TR23MY23.018

 is first a maximum during the maneuver prescribed in section 
(c)(5)(viii) of this paragraph,
nzw = Load factor normal to the flight path at 
VCLmax,
W = Airplane gross weight,
    S = Aerodynamic reference wing area; and
q = Dynamic pressure.

    (5) 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 center of gravity position that results in the highest 
value of reference stall speed;
    (v) The airplane trimmed for straight flight at a speed achievable 
by the automatic trim system, but not less than 1.13 VSR and 
not greater than 1.3 VSR;
    (vi) Reserved.
    (vii) The high-incidence protection system adjusted, at the option 
of the applicant, to allow higher incidence than is possible with the 
normal production system; and
    (viii) Starting from the stabilized trim condition, apply the 
longitudinal control to decelerate the airplane so that the speed 
reduction does not exceed 1 knot per second.

(d) Stall Warning

    In lieu of Sec.  25.207, the following requirements apply:
(1) Normal Operation
    If the design meets all conditions of Part 1, section (b) of these 
special conditions, then the airplane need not provide stall warning 
during normal operation. The conditions of section (b) provide an 
equivalent level of safety to Sec.  25.207, Stall Warning, so the 
provision of an additional, unique warning device is not required.
(2) High-Incidence Protection System Failure
    For any failure of the high-incidence protection system that the 
applicant cannot show to be extremely improbable, and that results in 
the capability of the system no longer satisfying conditions (b)(1), 
(b)(2), and (b)(3), 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 meet 
the requirements

[[Page 32954]]

specified in conditions (d)(2)(iv) and (d)(2)(v) below.
    (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 
give clearly distinguishable indications under expected conditions of 
flight. However, a visual stall warning device that requires the 
attention of the crew 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 condition (d)(2)(i) above 
and for the conditions prescribed below in conditions (d)(2)(iv) and 
(d)(2)(v) below.
    (iv) In non-icing conditions, stall warning must provide sufficient 
margin to prevent encountering unacceptable characteristics and 
encountering stall in the following conditions:
    (A) In power-off straight deceleration not exceeding 1 knot per 
second to a speed 5 knots or 5 percent calibrated airspeed (CAS), 
whichever is greater, below the warning onset.
    (B) 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, 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 and distinctive indication of an 
acceptable nature that the airplane is stalled. Acceptable indications 
of a stall, occurring either individually or in combination are:
    (A) A nose-down pitch that cannot be readily arrested;
    (B) Buffeting, of a magnitude and severity that is strong and 
effective deterrent to further speed reduction; or
    (C) 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 aircraft 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.

(e) Handling Characteristics at High Incidence

    In lieu of both Sec.  25.201 and Sec.  25.203, the following apply:
(1) High-Incidence Handling Demonstrations
    In lieu of Sec.  25.201: the following apply:
    (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:
    (A) The high-incidence protection system operating normally;
    (B) Initial power conditions of:
    (1) Power off; and
    (2) The power necessary to maintain level flight at 1.5 
VSR1, where VSR1 is the reference stall speed 
with flaps in approach position, the landing gear retracted, and 
maximum landing weight;
    (C) None;
    (D) Flaps, landing gear, and deceleration devices in any likely 
combination of positions;
    (E) Representative weights within the range for which certification 
is requested; and
    (F) The airplane trimmed for straight flight at a speed achievable 
by the automatic trim system.
    (ii) The following procedures must be used to show compliance in 
non-icing and icing conditions:
    (A) 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.
    (B) 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.
    (C) Maneuvers with increased deceleration rates:
    (1) 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.
    (2) 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 3 knots per second.
    (D) Maneuvers with ice accretion prior to operation of the normal 
anti-ice system: With the ice accretion prior to operation of the 
normal anti-ice system, the requirement must also be met in 
deceleration at 1 knot per second up to full back stick.
(2) Characteristics in High-Incidence Maneuvers
    In lieu of Sec.  25.203, the following apply in icing and non-icing 
conditions:
    (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:
    (A) There must not be any abnormal nose-up pitching.
    (B) 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.
    (C) 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.
    (D) The airplane must not exhibit buffeting of a magnitude and 
severity that would act as a deterrent from completing the maneuver 
specified in (e)(1)(i).
    (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 longitudinal control on the 
stop for a period of time appropriate to the maneuver.
    (iii) It must always be possible 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.
(3) Characteristics Up to Maximum Lift Angle of Attack
    (i) In non-icing conditions:
    Maneuvers with a rate of deceleration of not more than 1 knot per 
second up to the AoA at which VCLmax was obtained, as 
defined in section (c) of these special conditions, must be 
demonstrated in straight flight and in 30-degree banked turns in the 
following configurations:
    (A) The high-incidence protection deactivated or adjusted, at the 
option of the applicant, to allow higher incidence than is possible 
with the normal production system;

[[Page 32955]]

    (B) Automatic thrust increase system inhibited (if applicable);
    (C) Engines idling;
    (D) Flaps and landing gear in any likely combination of positions; 
and
    (E) The airplane trimmed for straight flight at a speed achievable 
by the automatic trim system.
    (ii) In icing conditions:
    Maneuvers with a rate of deceleration of not more than 1 knot per 
second up to the maximum AoA reached during maneuvers from section 
(e)(1)(ii)(C)(2) must be demonstrated in straight flight with:
    (A) The high-incidence protection deactivated or adjusted, at the 
option of the applicant, to allow higher incidence than is possible 
with the normal production system;
    (B) Automatic thrust increase system inhibited (if applicable);
    (C) Engines idling;
    (D) Flaps and landing gear in any likely combination of positions; 
and
    (E) The airplane trimmed for straight flight at a speed achievable 
by the automatic trim system.
    (iii) During the maneuvers used to show compliance with sections 
(e)(3)(i) and (e)(3)(ii) above, the airplane must not exhibit dangerous 
characteristics and it must always be possible to reduce AoA by 
conventional use of the controls. The pilot must retain good lateral 
and directional control, by conventional use of the controls, 
throughout the maneuver.

(f) Atmospheric Disturbances

    Operation of the high-incidence protection system must not 
adversely affect aircraft 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.

(g) Proof of Compliance

    In lieu of Sec.  25.21(b), the design must meet the following 
requirement:
    (b) The flying qualities must be evaluated at the most unfavorable 
center-of-gravity (CG) position.

(h) Sections 25.145(a), 25.145(b)(6), and 25.1323(d)

    The design must meet the following modified requirements:

 Section 25.145(a) ``Vmin'' in lieu of ``stall 
identification''
 Section 25.145(b)(6) ``Vmin'' in lieu of 
VSW
 Section 25.1323(d) ``From 1.23 VSR to 
Vmin. . .,'' in lieu of ``1.23 VSR to stall 
warning speed. . .,'' and ``speeds below Vmin. . .'' in lieu 
of ``speeds below stall warning. . .''.

Special Conditions Part II: Credit for Robust Envelope Protection in 
Icing Conditions

    (a) In lieu of Sec.  25.21(g)(1), the following requirement 
applies: Sec.  25.21, Proof of compliance:
    (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, 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.
    (b) In lieu of Sec.  25.103, define the stall speed as provided in 
Special Conditions Part I, section (c).
    (c) In lieu of Sec.  25.105(a)(2)(i), the following applies:
    Section 25.105, Take-off:
    (2) In icing conditions, if in the configuration of Sec.  25.121(b) 
with the ``Take-off Ice'' accretion defined in appendix C:
    (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
    (d) In lieu of Sec.  25.107(c) and (g), the following apply, with 
additional sections (c') and (g'):
    Section 25.107, Take-Off Speeds:
    (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 ``take-off ice'' accretion 
defined in part 25, appendix C, V2 may not be less than--
    (1) the V2 speed determined in non-icing conditions; and
    (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--
    (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 take-off ice'' accretion 
defined in part 25, appendix C, 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).
    (e) 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:
    Section 25.121, Climb: One-Engine Inoperative:
    In lieu of Sec.  25.121(b)(2)(ii)(A):
    (A) The V2 speed scheduled in non-icing conditions does 
not provide the maneuvering capability specified in Sec.  25.143(h) for 
the take-off configuration; or
    In lieu of Sec.  25.121(c)(2)(ii)(A):
    (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
    In lieu of Sec.  25.121(d)(2)(ii):
    (d)(2) The requirements of sub-paragraph (d)(1) of this paragraph 
must be met:
    (ii) In icing conditions with the approach ice accretion defined in 
part 25, appendix C, 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.VSR (VSR determined in non-icing 
conditions).
    (f) In lieu of Sec.  25.123(b)(2)(i), the following requirements 
apply:
    Section 25.123, En-route flight paths.
    (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
    (g) In lieu of Sec.  25.125(b)(2)(ii)(B), replace with the 
following requirements and remove Sec.  25.125(b)(2)(ii)(C):
    Section 25.125, Landing.
    (B) A speed that provides the maneuvering capability specified in 
Sec.  25.143(h) with the landing ice accretion defined in part 25, 
appendix C.
    (C) [removed].
    (h) In lieu of Sec.  25.143(j)(1), the following applies:

[[Page 32956]]

    Section 25.143, General.
    (1) The airplane is controllable in a pull-up maneuver up to 1.5g 
load factor or lower if limited by AoA protection.
    (i) In lieu of Sec.  25.207, Stall warning, change to read as the 
requirements defined in Part I Special Conditions, section (d).

    Issued in Des Moines, Washington, on May 18, 2023.
Suzanne A. Masterson,
Acting Manager, Technical Policy Branch, Policy and Standards Division, 
Aircraft Certification Service.
[FR Doc. 2023-10971 Filed 5-22-23; 8:45 am]
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