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14 CFR Ch. I (1–1–19 Edition)

§ 25.703

engines on one side of the plane of sym-
metry inoperative and the remaining
engines at takeoff power.

that are not subjected to slipstream
conditions, the structure must be de-
signed for the loads imposed when the
wing flaps or slats on one side are car-
rying the most severe load occurring in
the prescribed symmetrical conditions
and those on the other side are car-
rying not more than 80 percent of that
load.

(d) The interconnection must be de-

signed for the loads resulting when
interconnected flap or slat surfaces on
one side of the plane of symmetry are
jammed and immovable while the sur-
faces on the other side are free to move
and the full power of the surface actu-
ating system is applied.

[Amdt. 25–72, 55 FR 29777, July 20, 1990]

§ 25.703

Takeoff warning system.

A takeoff warning system must be in-

stalled and must meet the following re-
quirements:

(a) The system must provide to the

pilots an aural warning that is auto-
matically activated during the initial
portion of the takeoff roll if the air-
plane is in a configuration, including
any of the following, that would not
allow a safe takeoff:

(1) The wing flaps or leading edge de-

vices are not within the approved range
of takeoff positions.

(2) Wing spoilers (except lateral con-

trol spoilers meeting the requirements
of § 25.671), speed brakes, or longitu-
dinal trim devices are in a position
that would not allow a safe takeoff.

(b) The warning required by para-

graph (a) of this section must continue
until—

(1) The configuration is changed to

allow a safe takeoff;

(2) Action is taken by the pilot to

terminate the takeoff roll;

(3) The airplane is rotated for take-

off; or

(4) The warning is manually deacti-

vated by the pilot.

system must function properly
throughout the ranges of takeoff

weights, altitudes, and temperatures
for which certification is requested.

[Amdt. 25–42, 43 FR 2323, Jan. 16, 1978]

ANDING

EAR

§ 25.721

General.

(a) The landing gear system must be

designed so that when it fails due to
overloads during takeoff and landing,
the failure mode is not likely to cause
spillage of enough fuel to constitute a
fire hazard. The overloads must be as-
sumed to act in the upward and aft di-
rections in combination with side loads
acting inboard and outboard. In the ab-
sence of a more rational analysis, the
side loads must be assumed to be up to
20 percent of the vertical load or 20 per-
cent of the drag load, whichever is
greater.

(b) The airplane must be designed to

avoid any rupture leading to the spill-
age of enough fuel to constitute a fire
hazard as a result of a wheels-up land-
ing on a paved runway, under the fol-
lowing minor crash landing conditions:

(1) Impact at 5 feet-per-second

vertical velocity, with the airplane
under control, at Maximum Design
Landing Weight—

(i) With the landing gear fully re-

tracted; and

(ii) With any one or more landing

gear legs not extended.

(2) Sliding on the ground, with—
(i) The landing gear fully retracted

and with up to a 20

yaw angle; and

(ii) Any one or more landing gear

legs not extended and with 0

yaw

angle.

gine nacelle is likely to come into con-
tact with the ground, the engine pylon
or engine mounting must be designed
so that when it fails due to overloads
(assuming the overloads to act pre-
dominantly in the upward direction
and separately, predominantly in the
aft direction), the failure mode is not
likely to cause the spillage of enough
fuel to constitute a fire hazard.

[Amdt. 25–139, 79 FR 59430, Oct. 2, 2014]

§ 25.723

Shock absorption tests.

(a) The analytical representation of

the landing gear dynamic characteris-
tics that is used in determining the

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