214 

14 CFR Ch. I (1–1–24 Edition) 

§ 25.113 

(3) After reaching 

V

EF,

the airplane 

must be accelerated to 

V

2

. 

(b) During the acceleration to speed 

V

2

, the nose gear may be raised off the 

ground at a speed not less than 

V

R

. 

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

(c) During the takeoff path deter-

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 

V

2

before 

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

V

2

, 

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. 

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Federal Aviation Administration, DOT 

§ 25.119 

(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

2

before reaching 

35 feet above the takeoff surface, deter-
mined under § 25.111 for a wet runway. 

(c) If the takeoff distance does not in-

clude a clearway, the takeoff run is 
equal to the takeoff distance. If the 
takeoff distance includes a clearway— 

(1) The takeoff run on a dry runway 

is the greater of— 

(i) The horizontal distance along the 

takeoff path from the start of the take-
off to a point equidistant between the 
point at which V

LOF

is reached and the 

point at which the airplane is 35 feet 
above the takeoff surface, as deter-
mined under § 25.111 for a dry runway; 
or 

(ii) 115 percent of the horizontal dis-

tance along the takeoff path, with all 
engines operating, from the start of the 
takeoff to a point equidistant between 
the point at which V

LOF

is reached and 

the point at which the airplane is 35 
feet above the takeoff surface, deter-
mined by a procedure consistent with 
§ 25.111. 

(2) The takeoff run on a wet runway 

is the greater of— 

(i) 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

2

before reaching 

35 feet above the takeoff surface, as de-
termined under § 25.111 for a wet run-
way; or 

(ii) 115 percent of the horizontal dis-

tance along the takeoff path, with all 
engines operating, from the start of the 
takeoff to a point equidistant between 
the point at which V

LOF

is reached and 

the point at which the airplane is 35 
feet above the takeoff surface, deter-
mined by a procedure consistent with 
§ 25.111. 

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as 
amended by Amdt. 25–23, 35 FR 5671, Apr. 8, 
1970; Amdt. 25–92, 63 FR 8320, Feb. 18, 1998] 

§ 25.115

Takeoff flight path. 

(a) The takeoff flight path shall be 

considered to begin 35 feet above the 
takeoff surface at the end of the take-
off distance determined in accordance 
with § 25.113(a) or (b), as appropriate for 
the runway surface condition. 

(b) The net takeoff flight path data 

must be determined so that they rep-
resent the actual takeoff flight paths 
(determined in accordance with § 25.111 
and with paragraph (a) of this section) 
reduced at each point by a gradient of 
climb equal to— 

(1) 0.8 percent for two-engine air-

planes; 

(2) 0.9 percent for three-engine air-

planes; and 

(3) 1.0 percent for four-engine air-

planes. 

(c) The prescribed reduction in climb 

gradient may be applied as an equiva-
lent reduction in acceleration along 
that part of the takeoff flight path at 
which the airplane is accelerated in 
level flight. 

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as 
amended by Amdt. 25–92, 63 FR 8320, Feb. 18, 
1998] 

§ 25.117

Climb: general. 

Compliance with the requirements of 

§§ 25.119 and 25.121 must be shown at 
each weight, altitude, and ambient 
temperature within the operational 
limits established for the airplane and 
with the most unfavorable center of 
gravity for each configuration. 

§ 25.119

Landing climb: All-engines-op-

erating. 

In the landing configuration, the 

steady gradient of climb may not be 
less than 3.2 percent, with the engines 
at the power or thrust that is available 
8 seconds after initiation of movement 
of the power or thrust controls from 
the minimum flight idle to the go- 
around power or thrust setting— 

(a) In non-icing conditions, with a 

climb speed of V

REF

determined in ac-

cordance with § 25.125(b)(2)(i); and 

(b) In 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), and with a climb speed of 

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