211 

Federal Aviation Administration, DOT 

§ 25.107 

to stop the airplane during accelerate- 
stop tests. 

(b) 

V

2MIN,

in terms of calibrated air-

speed, may not be less than— 

(1) 1.13 

V

SR

for— 

(i) Two-engine and three-engine tur-

bopropeller and reciprocating engine 
powered airplanes; and 

(ii) Turbojet powered airplanes with-

out provisions for obtaining a signifi-
cant reduction in the one-engine-inop-
erative power-on stall speed; 

(2) 1.08 

V

SR

for— 

(i) Turbopropeller and reciprocating 

engine powered airplanes with more 
than three engines; and 

(ii) Turbojet powered airplanes with 

provisions for obtaining a significant 
reduction in the one-engine-inoper-
ative power-on stall speed; and 

(3) 1.10 times 

V

MC

established under 

§ 25.149. 

(c) 

V

2

, in terms of calibrated air-

speed, must be selected by the appli-
cant to provide at least the gradient of 
climb required by § 25.121(b) but may 
not be less than— 

(1) V

2MIN

; 

(2) 

V

R

plus the speed increment at-

tained (in accordance with § 25.111(c)(2)) 
before reaching a height of 35 feet 
above the takeoff surface; and 

(3) A speed that provides the maneu-

vering capability specified in § 25.143(h). 

(d) V

MU

is the calibrated airspeed at 

and above which the airplane can safe-
ly lift off the ground, and con- tinue 
the takeoff. V

MU

speeds must be se-

lected by the applicant throughout the 
range of thrust-to-weight ratios to be 
certificated. These speeds may be es-
tablished from free air data if these 
data are verified by ground takeoff 
tests. 

(e) 

V

R,

in terms of calibrated air-

speed, must be selected in accordance 
with the conditions of paragraphs (e)(1) 
through (4) of this section: 

(1) 

V

R

may not be less than— 

(i) 

V

1

; 

(ii) 105 percent of 

V

MC

; 

(iii) The speed (determined in accord-

ance with § 25.111(c)(2)) that allows 
reaching 

V

2

before reaching a height of 

35 feet above the takeoff surface; or 

(iv) A speed that, if the airplane is 

rotated at its maximum practicable 
rate, will result in a V

LOF

of not less 

than — 

(A) 110 percent of V

MU

in the all-en-

gines-operating condition, and 105 per-
cent of V

MU

determined at the thrust- 

to-weight ratio corresponding to the 
one-engine-inoperative condition; or 

(B) If the V

MU

attitude is limited by 

the geometry of the airplane (

i.e., 

tail 

contact with the runway), 108 percent 
of V

MU

in the all-engines-operating 

condition, and 104 percent of V

MU

deter-

mined at the thrust-to-weight ratio 
corresponding to the one-engine-inop-
erative condition. 

(2) For any given set of conditions 

(such as weight, configuration, and 
temperature), a single value of 

V

R,

ob-

tained in accordance with this para-
graph, must be used to show compli-
ance with both the one-engine-inoper-
ative and the all-engines-operating 
takeoff provisions. 

(3) It must be shown that the one-en-

gine-inoperative takeoff distance, 
using a rotation speed of 5 knots less 
than 

V

R

established in accordance with 

paragraphs (e)(1) and (2) of this section, 
does not exceed the corresponding one- 
engine-inoperative takeoff distance 
using the established 

V

R

. The takeoff 

distances must be determined in ac-
cordance with § 25.113(a)(1). 

(4) Reasonably expected variations in 

service from the established takeoff 
procedures for the operation of the air-
plane (such as over-rotation of the air-
plane and out-of-trim conditions) may 
not result in unsafe flight characteris-
tics or in marked increases in the 
scheduled takeoff distances established 
in accordance with § 25.113(a). 

(f) 

V

LOF

is the calibrated airspeed at 

which the airplane first becomes air-
borne. 

(g) 

V

FTO

, in terms of calibrated air-

speed, must be selected by the appli-
cant to provide at least the gradient of 
climb required by § 25.121(c), but may 
not be less than— 

(1) 1.18 

V

SR

; and 

(2) A speed that provides the maneu-

vering capability specified in § 25.143(h). 

(h) In determining the takeoff speeds 

V

1

, V

R

, and V

2

for flight in icing condi-

tions, the values of V

MCG

, V

MC

, and V

MU

 

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