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380 

14 CFR Ch. I (1–1–14 Edition) 

§ 25.113 

(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 takeoff ice accretion de-

fined in appendix C, from a height of 35 
feet above the takeoff surface up to the 
point where the airplane is 400 feet 
above the takeoff surface; and 

(ii) With the final takeoff ice accre-

tion defined in appendix C, 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] 

§ 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

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 

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