230
14 CFR Ch. I (1–1–19 Edition)
§ 25.233
for takeoff, taxiing, and landing, must
be established.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25–108, 67 FR 70828, Nov.
26, 2002]
§ 25.233
Directional stability and con-
trol.
(a) There may be no uncontrollable
ground-looping tendency in 90
°
cross
winds, up to a wind velocity of 20 knots
or 0.2
V
SR
0
, whichever is greater, except
that the wind velocity need not exceed
25 knots at any speed at which the air-
plane may be expected to be operated
on the ground. This may be shown
while establishing the 90
°
cross compo-
nent of wind velocity required by
§ 25.237.
(b) Landplanes must be satisfactorily
controllable, without exceptional pilot-
ing skill or alertness, in power-off land-
ings at normal landing speed, without
using brakes or engine power to main-
tain a straight path. This may be
shown during power-off landings made
in conjunction with other tests.
(c) The airplane must have adequate
directional control during taxiing. This
may be shown during taxiing prior to
takeoffs made in conjunction with
other tests.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25–23, 35 FR 5671, Apr. 8,
1970; Amdt. 25–42, 43 FR 2322, Jan. 16, 1978;
Amdt. 25–94, 63 FR 8848, Feb. 23, 1998; Amdt.
25–108, 67 FR 70828, Nov. 26, 2002]
§ 25.235
Taxiing condition.
The shock absorbing mechanism may
not damage the structure of the air-
plane when the airplane is taxied on
the roughest ground that may reason-
ably be expected in normal operation.
§ 25.237
Wind velocities.
(a) For land planes and amphibians,
the following applies:
(1) A 90-degree cross component of
wind velocity, demonstrated to be safe
for takeoff and landing, must be estab-
lished for dry runways and must be at
least 20 knots or 0.2 V
SR0
, whichever is
greater, except that it need not exceed
25 knots.
(2) The crosswind component for
takeoff established without ice accre-
tions is valid in icing conditions.
(3) The landing crosswind component
must be established for:
(i) Non-icing conditions, and
(ii) Icing conditions with the most
critical of the landing ice accretion(s)
defined in Appendices C and O of this
part, as applicable, in accordance with
§ 25.21(g).
(b) For seaplanes and amphibians,
the following applies:
(1) A 90-degree cross component of
wind velocity, up to which takeoff and
landing is safe under all water condi-
tions that may reasonably be expected
in normal operation, must be estab-
lished and must be at least 20 knots or
0.2 V
SR
0
, whichever is greater, except
that it need not exceed 25 knots.
(2) A wind velocity, for which taxiing
is safe in any direction under all water
conditions that may reasonably be ex-
pected in normal operation, must be es-
tablished and must be at least 20 knots
or 0.2 V
SR0
, whichever is greater, except
that it need not exceed 25 knots.
[Amdt. 25–42, 43 FR 2322, Jan. 16, 1978, as
amended by Amdt. 25–108, 67 FR 70827, Nov.
26, 2002; Amdt. 25–121, 72 FR 44668, Aug. 8,
2007; Amdt. 25–140, 79 FR 65525, Nov. 4, 2014]
§ 25.239
Spray characteristics, control,
and stability on water.
(a) For seaplanes and amphibians,
during takeoff, taxiing, and landing,
and in the conditions set forth in para-
graph (b) of this section, there may be
no—
(1) Spray characteristics that would
impair the pilot’s view, cause damage,
or result in the taking in of an undue
quantity of water;
(2) Dangerously uncontrollable
porpoising, bounding, or swinging tend-
ency; or
(3) Immersion of auxiliary floats or
sponsons, wing tips, propeller blades,
or other parts not designed to with-
stand the resulting water loads.
(b) Compliance with the require-
ments of paragraph (a) of this section
must be shown—
(1) In water conditions, from smooth
to the most adverse condition estab-
lished in accordance with § 25.231;
(2) In wind and cross-wind velocities,
water currents, and associated waves
and swells that may reasonably be ex-
pected in operation on water;
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