title-14-part-25-sec25-111

213

Federal Aviation Administration, DOT

§ 25.111

system efficiency, if determined, is ap-
propriate for a grooved or porous fric-
tion course wet runway, and the max-

imum tire-to-ground wet runway brak-
ing coefficient of friction is defined as:

Where—

Tire Pressure = maximum airplane operating

tire pressure (psi);

t/gMAX

= maximum tire-to-ground braking

coefficient;

V = airplane true ground speed (knots); and
Linear interpolation may be used for tire

pressures other than those listed.

(e) Except as provided in paragraph

(f)(1) of this section, means other than
wheel brakes may be used to determine
the accelerate-stop distance if that
means—

(1) Is safe and reliable;
(2) Is used so that consistent results

can be expected under normal oper-
ating conditions; and

(3) Is such that exceptional skill is

not required to control the airplane.

(f) The effects of available reverse

thrust—

(1) Shall not be included as an addi-

tional means of deceleration when de-
termining the accelerate-stop distance
on a dry runway; and

(2) May be included as an additional

means of deceleration using rec-
ommended reverse thrust procedures
when determining the accelerate-stop
distance on a wet runway, provided the
requirements of paragraph (e) of this
section are met.

(g) The landing gear must remain ex-

tended throughout the accelerate-stop
distance.

(h) If the accelerate-stop distance in-

cludes a stopway with surface charac-
teristics substantially different from

those of the runway, the takeoff data
must include operational correction
factors for the accelerate-stop dis-
tance. The correction factors must ac-
count for the particular surface charac-
teristics of the stopway and the vari-
ations in these characteristics with
seasonal weather conditions (such as
temperature, rain, snow, and ice) with-
in the established operational limits.

(i) A flight test demonstration of the

maximum brake kinetic energy accel-
erate-stop distance must be conducted
with not more than 10 percent of the
allowable brake wear range remaining
on each of the airplane wheel brakes.

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25–42, 43 FR 2321, Jan. 16,
1978; Amdt. 25–92, 63 FR 8318, Feb. 18, 1998]

§ 25.111

Takeoff path.

(a) The takeoff path extends from a

standing start to a point in the takeoff
at which the airplane is 1,500 feet above
the takeoff surface, or at which the
transition from the takeoff to the en
route configuration is completed and
V

FTO

is reached, whichever point is

higher. In addition—

(1) The takeoff path must be based on

the procedures prescribed in § 25.101(f);

(2) The airplane must be accelerated

on the ground to

EF,

at which point

the critical engine must be made inop-
erative and remain inoperative for the
rest of the takeoff; and

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214

14 CFR Ch. I (1–1–24 Edition)

§ 25.113

(3) After reaching

EF,

the airplane

must be accelerated to

(b) During the acceleration to speed

, the nose gear may be raised off the

ground at a speed not less than

However, landing gear retraction may
not be begun until the airplane is air-
borne.

mination in accordance with para-
graphs (a) and (b) of this section—

(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.