title-14-part-25-sec25-143

218

14 CFR Ch. I (1–1–24 Edition)

§ 25.143

more than 5 knots CAS at the max-
imum landing weight.

(b) In determining the distance in

paragraph (a) of this section:

(1) The airplane must be in the land-

ing configuration.

(2) A stabilized approach, with a cali-

brated airspeed of not less than V

REF

must be maintained down to the 50-foot
height.

(i) In non-icing conditions, V

REF

may

not be less than:

(A) 1.23 V

(B) V

MCL

established under § 25.149(f);

and

vering capability specified in § 25.143(h).

(ii) In icing conditions, V

REF

may not

be less than:

(A) The speed determined in para-

graph (b)(2)(i) of this section;

(B) 1.23 V

SR0

with the most critical of

the landing ice accretion(s) defined in
Appendices C and O of this part, as ap-
plicable, in accordance with § 25.21(g), if
that speed exceeds V

REF

selected for

non-icing conditions by more than 5
knots CAS; and

vering capability specified in § 25.143(h)
with the most critical of the landing
ice accretion(s) defined in Appendices C
and O of this part, as applicable, in ac-
cordance with § 25.21(g).

(3) Changes in configuration, power

or thrust, and speed, must be made in
accordance with the established proce-
dures for service operation.

(4) The landing must be made with-

out excessive vertical acceleration,
tendency to bounce, nose over, ground
loop, porpoise, or water loop.

(5) The landings may not require ex-

ceptional piloting skill or alertness.

the landing distance on land must be
determined on a level, smooth, dry,
hard-surfaced runway. In addition—

(1) The pressures on the wheel brak-

ing systems may not exceed those spec-
ified by the brake manufacturer;

(2) The brakes may not be used so as

to cause excessive wear of brakes or
tires; and

(3) Means other than wheel brakes

may be used if that means—

(i) Is safe and reliable;
(ii) Is used so that consistent results

can be expected in service; and

(iii) Is such that exceptional skill is

not required to control the airplane.

(d) For seaplanes and amphibians,

the landing distance on water must be
determined on smooth water.

(e) For skiplanes, the landing dis-

tance on snow must be determined on
smooth, dry, snow.

(f) The landing distance data must

include correction factors for not more
than 50 percent of the nominal wind
components along the landing path op-
posite to the direction of landing, and
not less than 150 percent of the nomi-
nal wind components along the landing
path in the direction of landing.

(g) If any device is used that depends

on the operation of any engine, and if
the landing distance would be notice-
ably increased when a landing is made
with that engine inoperative, the land-
ing distance must be determined with
that engine inoperative unless the use
of compensating means will result in a
landing distance not more than that
with each engine operating.

[Amdt. 25–121, 72 FR 44666; Aug. 8, 2007; 72 FR
50467, Aug. 31, 2007; Amdt. 25–140, 79 FR 65525,
Nov. 4, 2014]

ONTROLLABILITY AND

ANEUVERABILITY

§ 25.143

General.

(a) The airplane must be safely con-

trollable and maneuverable during—

(1) Takeoff;
(2) Climb;
(3) Level flight;
(4) Descent; and
(5) Landing.
(b) It must be possible to make a

smooth transition from one flight con-
dition to any other flight condition
without exceptional piloting skill,
alertness, or strength, and without
danger of exceeding the airplane limit-
load factor under any probable oper-
ating conditions, including—

(1) The sudden failure of the critical

engine;

(2) For airplanes with three or more

engines, the sudden failure of the sec-
ond critical engine when the airplane is
in the en route, approach, or landing
configuration and is trimmed with the
critical engine inoperative; and

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Federal Aviation Administration, DOT

§ 25.143

(3) Configuration changes, including

deployment or retraction of decelera-
tion devices.

safely controllable and maneuverable
with the most critical of the ice accre-
tion(s) appropriate to the phase of
flight as defined in Appendices C and O
of this part, as applicable, in accord-
ance with § 25.21(g), and with the crit-
ical engine inoperative and its pro-
peller (if applicable) in the minimum
drag position:

(1) At the minimum V

for takeoff;

(2) During an approach and go-

around; and

(3) During an approach and landing.
(d) The following table prescribes, for

conventional wheel type controls, the
maximum control forces permitted
during the testing required by para-
graph (a) through (c) of this section:

Force, in pounds, applied to the

control wheel or rudder pedals

Pitch Roll Yaw

For short term application for

pitch and roll control—two
hands available for control ....

For short term application for

pitch and roll control—one
hand available for control ......

For short term application for

yaw control .............................

150

For long term application ..........

(e) Approved operating procedures or

conventional operating practices must
be followed when demonstrating com-
pliance with the control force limita-
tions for short term application that

are prescribed in paragraph (d) of this
section. The airplane must be in trim,
or as near to being in trim as practical,
in the preceding steady flight condi-
tion. For the takeoff condition, the air-
plane must be trimmed according to
the approved operating procedures.

(f) When demonstrating compliance

with the control force limitations for
long term application that are pre-
scribed in paragraph (d) of this section,
the airplane must be in trim, or as near
to being in trim as practical.

(g) When maneuvering at a constant

airspeed or Mach number (up to V

), the stick forces and the gradient

of the stick force versus maneuvering
load factor must lie within satisfactory
limits. The stick forces must not be so
great as to make excessive demands on
the pilot’s strength when maneuvering
the airplane, and must not be so low
that the airplane can easily be over-
stressed inadvertently. Changes of gra-
dient that occur with changes of load
factor must not cause undue difficulty
in maintaining control of the airplane,
and local gradients must not be so low
as to result in a danger of overcontrol-
ling.

(h) The maneuvering capabilities in a

constant speed coordinated turn at for-
ward center of gravity, as specified in
the following table, must be free of
stall warning or other characteristics
that might interfere with normal ma-
neuvering:

Configuration Speed

Maneuvering

bank angle in a

coordinated turn

Thrust/power setting

Takeoff ..........

Asymmetric WAT-Limited.

Takeoff ..........

+ XX

All-engines-operating climb.

En route ........

FTO

Asymmetric WAT-Limited.

Landing .........

REF

Symmetric for

flight path angle.

A combination of weight, altitude, and temperature (WAT) such that the thrust or power setting produces the minimum climb

gradient specified in § 25.121 for the flight condition.

Airspeed approved for all-engines-operating initial climb.

That thrust or power setting which, in the event of failure of the critical engine and without any crew action to adjust the thrust

or power of the remaining engines, would result in the thrust or power specified for the takeoff condition at V

, or any lesser

thrust or power setting that is used for all-engines-operating initial climb procedures.

(i) When demonstrating compliance

with § 25.143 in icing conditions—

(1) Controllability must be dem-

onstrated with the most critical of the
ice accretion(s) for the particular
flight phase as defined in Appendices C
and O of this part, as applicable, in ac-
cordance with § 25.21(g);

(2) It must be shown that a push force

is required throughout a pushover ma-
neuver down to a zero g load factor, or
the lowest load factor obtainable if
limited by elevator power or other de-
sign characteristic of the flight control
system. It must be possible to prompt-
ly recover from the maneuver without

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14 CFR Ch. I (1–1–24 Edition)

§ 25.145

exceeding a pull control force of 50
pounds; and

(3) Any changes in force that the

pilot must apply to the pitch control to
maintain speed with increasing sideslip
angle must be steadily increasing with
no force reversals, unless the change in
control force is gradual and easily con-
trollable by the pilot without using ex-
ceptional piloting skill, alertness, or
strength.

(j) For flight in icing conditions be-

fore the ice protection system has been
activated and is performing its in-
tended function, it must be dem-
onstrated in flight with the most crit-
ical of the ice accretion(s) defined in
Appendix C, part II, paragraph (e) of
this part and Appendix O, part II, para-
graph (d) of this part, as applicable, in
accordance with § 25.21(g), that:

(1) The airplane is controllable in a

pull-up maneuver up to 1.5 g load fac-
tor; and

(2) There is no pitch control force re-

versal during a pushover maneuver
down to 0.5 g load factor.

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25–42, 43 FR 2321, Jan. 16,
1978; Amdt. 25–84, 60 FR 30749, June 9, 1995;
Amdt. 25–108, 67 FR 70826, Nov. 26, 2002;
Amdt. 25–121, 72 FR 44667, Aug. 8, 2007; Amdt.
25–129, 74 FR 38339, Aug. 3, 2009; Amdt. 25–140,
79 FR 65525, Nov. 4, 2014]

§ 25.145

Longitudinal control.

(a) It must be possible, at any point

between the trim speed prescribed in
§ 25.103(b)(6) and stall identification (as
defined in § 25.201(d)), to pitch the nose
downward so that the acceleration to
this selected trim speed is prompt with

(1) The airplane trimmed at the trim

speed prescribed in § 25.103(b)(6);

(2) The landing gear extended;
(3) The wing flaps (i) retracted and

(ii) extended; and

(4) Power (i) off and (ii) at maximum

continuous power on the engines.

(b) With the landing gear extended,

no change in trim control, or exertion
of more than 50 pounds control force
(representative of the maximum short
term force that can be applied readily
by one hand) may be required for the
following maneuvers:

(1) With power off, flaps retracted,

and the airplane trimmed at 1.3 V

SR1

extend the flaps as rapidly as possible

while maintaining the airspeed at ap-
proximately 30 percent above the ref-
erence stall speed existing at each in-
stant throughout the maneuver.

(2) Repeat paragraph (b)(1) except ini-

tially extend the flaps and then retract
them as rapidly as possible.

(3) Repeat paragraph (b)(2), except at

the go-around power or thrust setting.

(4) With power off, flaps retracted,

and the airplane trimmed at 1.3 V

SR1

rapidly set go-around power or thrust
while maintaining the same airspeed.

(5) Repeat paragraph (b)(4) except

with flaps extended.

(6) With power off, flaps extended,

and the airplane trimmed at 1.3 V

SR1

obtain and maintain airspeeds between
V

and either 1.6 V

SR1

or V

, which-

ever is lower.

ceptional piloting skill, to prevent loss
of altitude when complete retraction of
the high lift devices from any position
is begun during steady, straight, level
flight at 1.08 V

SR1

for propeller powered

airplanes, or 1.13 V

SR1

for turbojet pow-

ered airplanes, with—

(1) Simultaneous movement of the

power or thrust controls to the go-
around power or thrust setting;

(2) The landing gear extended; and
(3) The critical combinations of land-

ing weights and altitudes.

(d) If gated high-lift device control

positions are provided, paragraph (c) of
this section applies to retractions of
the high-lift devices from any position
from the maximum landing position to
the first gated position, between gated
positions, and from the last gated posi-
tion to the fully retracted position.
The requirements of paragraph (c) of
this section also apply to retractions
from each approved landing position to
the control position(s) associated with
the high-lift device configuration(s)
used to establish the go-around proce-
dure(s) from that landing position. In
addition, the first gated control posi-
tion from the maximum landing posi-
tion must correspond with a configura-
tion of the high-lift devices used to es-
tablish a go-around procedure from a
landing configuration. Each gated con-
trol position must require a separate
and distinct motion of the control to
pass through the gated position and

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