Section 23.2140

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

(b) The airplane must be able to complete a landing without causing substantial damage or serious injury using
the steepest approved approach gradient procedures and providing a reasonable margin below Vref or above approach angle of attack.
(c) VMC is the calibrated airspeed at
which, following the sudden critical
loss of thrust, it is possible to maintain
control of the airplane. For multiengine airplanes, the applicant must determine VMC, if applicable, for the most
critical configurations used in takeoff
and landing operations.
(d) If the applicant requests certification of an airplane for aerobatics,
the applicant must demonstrate those
aerobatic maneuvers for which certification is requested and determine
entry speeds.
Section 23.2140

Trim.

(a) The airplane must maintain lateral and directional trim without further force upon, or movement of, the
primary
flight
controls
or
corresponding trim controls by the pilot,
or the flight control system, under the
following conditions:
(1) For levels 1, 2, and 3 airplanes in
cruise.
(2) For level 4 airplanes in normal operations.
(b) The airplane must maintain longitudinal trim without further force
upon, or movement of, the primary
flight controls or corresponding trim
controls by the pilot, or the flight control system, under the following conditions:
(1) Climb.
(2) Level flight.
(3) Descent.
(4) Approach.
(c) Residual control forces must not
fatigue or distract the pilot during normal operations of the airplane and
likely abnormal or emergency operations, including a critical loss of
thrust on multiengine airplanes.

spaschal on DSK3GDR082PROD with CFR

Section 23.2145

Stability.

(a) Airplanes not certified for aerobatics must - 
(1) Have static longitudinal, lateral,
and directional stability in normal operations;

(2) Have dynamic short period and
Dutch roll stability in normal operations; and
(3) Provide stable control force feedback throughout the operating envelope.
(b) No airplane may exhibit any divergent longitudinal stability characteristic so unstable as to increase
the pilot-s workload or otherwise endanger the airplane and its occupants.
Section 23.2150 Stall characteristics,
warning, and spins.

(a) The airplane must have controllable stall characteristics in straight
flight, turning flight, and accelerated
turning flight with a clear and distinctive stall warning that provides sufficient margin to prevent inadvertent
stalling.
(b) Single-engine airplanes, not certified for aerobatics, must not have a
tendency to inadvertently depart controlled flight.
(c) Levels 1 and 2 multiengine airplanes, not certified for aerobatics,
must not have a tendency to inadvertently depart controlled flight from
thrust asymmetry after a critical loss
of thrust.
(d) Airplanes certified for aerobatics
that include spins must have controllable stall characteristics and the ability to recover within one and one-half
additional turns after initiation of the
first control action from any point in a
spin, not exceeding six turns or any
greater number of turns for which certification is requested, while remaining
within the operating limitations of the
airplane.
(e) Spin characteristics in airplanes
certified for aerobatics that includes
spins must recover without exceeding
limitations and may not result in unrecoverable spins - 
(1) With any typical use of the flight
or engine power controls; or
(2) Due to pilot disorientation or incapacitation.
Section 23.2155 Ground and water handling
characteristics.
For airplanes intended for operation
on land or water, the airplane must

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