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215

Federal Aviation Administration, DOT

§ 25.113

(1) The slope of the airborne part of

the takeoff path must be positive at
each point;

(2) The airplane must reach

before

it is 35 feet above the takeoff surface
and must continue at a speed as close
as practical to, but not less than

until it is 400 feet above the takeoff
surface;

(3) At each point along the takeoff

path, starting at the point at which the
airplane reaches 400 feet above the
takeoff surface, the available gradient
of climb may not be less than—

(i) 1.2 percent for two-engine air-

planes;

(ii) 1.5 percent for three-engine air-

planes; and

(iii) 1.7 percent for four-engine air-

planes.

(4) The airplane configuration may

not be changed, except for gear retrac-
tion and automatic propeller feath-
ering, and no change in power or thrust
that requires action by the pilot may
be made until the airplane is 400 feet
above the takeoff surface; and

(5) If § 25.105(a)(2) requires the takeoff

path to be determined for flight in
icing conditions, the airborne part of
the takeoff must be based on the air-
plane drag:

(i) With the most critical of the take-

off ice accretion(s) defined in Appen-
dices C and O of this part, as applica-
ble, in accordance with § 25.21(g), from
a height of 35 feet above the takeoff
surface up to the point where the air-
plane is 400 feet above the takeoff sur-
face; and

(ii) With the most critical of the final

takeoff ice accretion(s) defined in Ap-
pendices C and O of this part, as appli-
cable, in accordance with § 25.21(g),
from the point where the airplane is 400
feet above the takeoff surface to the
end of the takeoff path.

(d) The takeoff path must be deter-

mined by a continuous demonstrated
takeoff or by synthesis from segments.
If the takeoff path is determined by the
segmental method—

(1) The segments must be clearly de-

fined and must be related to the dis-
tinct changes in the configuration,
power or thrust, and speed;

(2) The weight of the airplane, the

configuration, and the power or thrust
must be constant throughout each seg-

ment and must correspond to the most
critical condition prevailing in the seg-
ment;

(3) The flight path must be based on

the airplane’s performance without
ground effect; and

(4) The takeoff path data must be

checked by continuous demonstrated
takeoffs up to the point at which the
airplane is out of ground effect and its
speed is stabilized, to ensure that the
path is conservative relative to the
continous path.

The airplane is considered to be out of
the ground effect when it reaches a
height equal to its wing span.

(e) For airplanes equipped with

standby power rocket engines, the
takeoff path may be determined in ac-
cordance with section II of appendix E.

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25–6, 30 FR 8468, July 2,
1965; Amdt. 25–42, 43 FR 2321, Jan. 16, 1978;
Amdt. 25–54, 45 FR 60172, Sept. 11, 1980; Amdt.
25–72, 55 FR 29774, July 20, 1990; Amdt. 25–94,
63 FR 8848, Feb. 23, 1998; Amdt. 25–108, 67 FR
70826, Nov. 26, 2002; Amdt. 25–115, 69 FR 40527,
July 2, 2004; Amdt. 25–121, 72 FR 44666; Aug.
8, 2007; Amdt. 25–140, 79 FR 65525, Nov. 4, 2014]

§ 25.113

Takeoff distance and takeoff

run.

(a) Takeoff distance on a dry runway

is the greater of—

(1) The horizontal distance along the

takeoff path from the start of the take-
off to the point at which the airplane is
35 feet above the takeoff surface, deter-
mined under § 25.111 for a dry runway;
or

(2) 115 percent of the horizontal dis-

tance along the takeoff path, with all
engines operating, from the start of the
takeoff to the point at which the air-
plane is 35 feet above the takeoff sur-
face, as determined by a procedure con-
sistent with § 25.111.

(b) Takeoff distance on a wet runway

is the greater of—

(1) The takeoff distance on a dry run-

way determined in accordance with
paragraph (a) of this section; or

(2) The horizontal distance along the

takeoff path from the start of the take-
off to the point at which the airplane is
15 feet above the takeoff surface,
achieved in a manner consistent with
the achievement of V

before reaching

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