Section 25.143

14 CFR Ch. I (1-1-19 Edition)

(2) During an approach and goaround; 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 paragraph (a) through (c) of this section:
Force, in pounds, applied to the
control wheel or rudder pedals

Pitch

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

Roll

Yaw

75

50

50

25

10

5

150
20

(e) Approved operating procedures or
conventional operating practices must
be followed when demonstrating compliance with the control force limitations 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 condition. For the takeoff condition, the airplane must be trimmed according to
the approved operating procedures.
Configuration
Takeoff ..........
Takeoff ..........
En route ........
Landing .........

Speed
V2
2V

2 + XX
VFTO
VREF

(f) When demonstrating compliance
with the control force limitations for
long 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.
(g) When maneuvering at a constant
airspeed or Mach number (up to VFC/
MFC), 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 overstressed inadvertently. Changes of gradient 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 overcontrolling.
(h) The maneuvering capabilities in a
constant speed coordinated turn at forward center of gravity, as specified in
the following table, must be free of
stall warning or other characteristics
that might interfere with normal maneuvering:

Maneuvering
bank angle in a
coordinated turn
30Section
40Section
40Section
40Section

Thrust/power setting
Asymmetric WAT-Limited. 1
All-engines-operating climb. 3
Asymmetric WAT-Limited. 1
Symmetric for Section3Section flight path angle.

spaschal on DSK3GDR082PROD with CFR

1 A combination of weight, altitude, and temperature (WAT) such that the thrust or power setting produces the minimum climb
gradient specified in Section 25.121 for the flight condition.
2 Airspeed approved for all-engines-operating initial climb.
3 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 V2, or any lesser
thrust or power setting that is used for all-engines-operating initial climb procedures.

(i) When demonstrating compliance
with Section 25.143 in icing conditions - 
(1) Controllability must be demonstrated 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 accordance with Section 25.21(g);
(2) It must be shown that a push force
is required throughout a pushover maneuver down to a zero g load factor, or
the lowest load factor obtainable if
limited by elevator power or other design characteristic of the flight control
system. It must be possible to prompt-

ly recover from the maneuver without
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 controllable by the pilot without using exceptional piloting skill, alertness, or
strength.
(j) For flight in icing conditions before the ice protection system has been

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