Code of Federal Regulations - Title 14

207

Federal Aviation Administration, DOT

§ 23.251

half additional turns after initiation of
the first control action for recovery.
However, beyond three turns, the spin
may be discontinued if spiral charac-
teristics appear.

(2) The applicable airspeed limits and

limit maneuvering load factors must
not be exceeded. For flaps-extended
configurations for which approval is re-
quested, the flaps must not be re-
tracted during the recovery.

(3) It must be impossible to obtain

unrecoverable spins with any use of the
flight or engine power controls either
at the entry into or during the spin.

(4) There must be no characteristics

during the spin (such as excessive rates
of rotation or extreme oscillatory mo-
tion) that might prevent a successful
recovery due to disorientation or inca-
pacitation of the pilot.

[Doc. No. 27807, 61 FR 5191, Feb. 9, 1996]

ROUND AND

ATER

ANDLING

HARACTERISTICS

§ 23.231

Longitudinal stability and

control.

(a) A landplane may have no uncon-

trollable tendency to nose over in any
reasonably expected operating condi-
tion, including rebound during landing
or takeoff. Wheel brakes must operate
smoothly and may not induce any
undue tendency to nose over.

(b) A seaplane or amphibian may not

have dangerous or uncontrollable
porpoising characteristics at any nor-
mal operating speed on the water.

§ 23.233

Directional stability and con-

trol.

(a) A 90 degree cross-component of

wind velocity, demonstrated to be safe
for taxiing, takeoff, and landing must
be established and must be not less
than 0.2 V

(b) The airplane must be satisfac-

torily controllable in power-off land-
ings at normal landing speed, without
using brakes or engine power to main-
tain a straight path until the speed has
decreased to at least 50 percent of the
speed at touchdown.

directional control during taxiing.

(d) Seaplanes must demonstrate sat-

isfactory directional stability and con-
trol for water operations up to the

maximum wind velocity specified in
paragraph (a) of this section.

[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as
amended by Amdt. 23–45, 58 FR 42159, Aug. 6,
1993; Amdt. 23–50, 61 FR 5192, Feb. 9, 1996]

§ 23.235

Operation on unpaved sur-

faces.

The airplane must be demonstrated

to have satisfactory characteristics
and the shock-absorbing mechanism
must not damage the structure of the
airplane when the airplane is taxied on
the roughest ground that may reason-
ably be expected in normal operation
and when takeoffs and landings are
performed on unpaved runways having
the roughest surface that may reason-
ably be expected in normal operation.

[Doc. No. 27807, 61 FR 5192, Feb. 9, 1996]

§ 23.237

Operation on water.

A wave height, demonstrated to be

safe for operation, and any necessary
water handling procedures for sea-
planes and amphibians must be estab-
lished.

[Doc. No. 27807, 61 FR 5192, Feb. 9, 1996]

§ 23.239

Spray characteristics.

Spray may not dangerously obscure

the vision of the pilots or damage the
propellers or other parts of a seaplane
or amphibian at any time during tax-
iing, takeoff, and landing.

ISCELLANEOUS

LIGHT

EQUIREMENTS

§ 23.251

Vibration and buffeting.

(a) There must be no vibration or

buffeting severe enough to result in
structural damage, and each part of
the airplane must be free from exces-
sive vibration, under any appropriate
speed and power conditions up to V

or V

for turbojets. In addi-

tion, there must be no buffeting in any
normal flight condition, including con-
figuration changes during cruise, se-
vere enough to interfere with the satis-
factory control of the airplane or cause
excessive fatigue to the flight crew.
Stall warning buffeting within these
limits is allowable.

(b) There must be no perceptible buf-

feting condition in the cruise configu-
ration in straight flight at any speed

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