219 

Federal Aviation Administration, DOT 

§ 25.143 

(A) 1.23 V

SR

0; 

(B) V

MCL

established under § 25.149(f); 

and 

(C) A speed that provides the maneu-

vering capability specified in § 25.143(h). 

(ii) In icing conditions, V

REF

may not 

be less than: 

(A) The speed determined in para-

graph (b)(2)(i) of this section; 

(B) 1.23 V

SR0

with the most critical of 

the landing ice accretion(s) defined in 
Appendices C and O of this part, as ap-
plicable, in accordance with § 25.21(g), if 
that speed exceeds V

REF

selected for 

non-icing conditions by more than 5 
knots CAS; and 

(C) A speed that provides the maneu-

vering capability specified in § 25.143(h) 
with the most critical of the landing 
ice accretion(s) defined in Appendices C 
and O of this part, as applicable, in ac-
cordance with § 25.21(g). 

(3) Changes in configuration, power 

or thrust, and speed, must be made in 
accordance with the established proce-
dures for service operation. 

(4) The landing must be made with-

out excessive vertical acceleration, 
tendency to bounce, nose over, ground 
loop, porpoise, or water loop. 

(5) The landings may not require ex-

ceptional piloting skill or alertness. 

(c) For landplanes and amphibians, 

the landing distance on land must be 
determined on a level, smooth, dry, 
hard-surfaced runway. In addition— 

(1) The pressures on the wheel brak-

ing systems may not exceed those spec-
ified by the brake manufacturer; 

(2) The brakes may not be used so as 

to cause excessive wear of brakes or 
tires; and 

(3) Means other than wheel brakes 

may be used if that means— 

(i) Is safe and reliable; 
(ii) Is used so that consistent results 

can be expected in service; and 

(iii) Is such that exceptional skill is 

not required to control the airplane. 

(d) For seaplanes and amphibians, 

the landing distance on water must be 
determined on smooth water. 

(e) For skiplanes, the landing dis-

tance on snow must be determined on 
smooth, dry, snow. 

(f) The landing distance data must 

include correction factors for not more 
than 50 percent of the nominal wind 
components along the landing path op-

posite to the direction of landing, and 
not less than 150 percent of the nomi-
nal wind components along the landing 
path in the direction of landing. 

(g) If any device is used that depends 

on the operation of any engine, and if 
the landing distance would be notice-
ably increased when a landing is made 
with that engine inoperative, the land-
ing distance must be determined with 
that engine inoperative unless the use 
of compensating means will result in a 
landing distance not more than that 
with each engine operating. 

[Amdt. 25–121, 72 FR 44666; Aug. 8, 2007; 72 FR 
50467, Aug. 31, 2007; Amdt. 25–140, 79 FR 65525, 
Nov. 4, 2014] 

C

ONTROLLABILITY AND

 

M

ANEUVERABILITY

 

§ 25.143

General. 

(a) The airplane must be safely con-

trollable and maneuverable during— 

(1) Takeoff; 
(2) Climb; 
(3) Level flight; 
(4) Descent; and 
(5) Landing. 
(b) It must be possible to make a 

smooth transition from one flight con-
dition to any other flight condition 
without exceptional piloting skill, 
alertness, or strength, and without 
danger of exceeding the airplane limit- 
load factor under any probable oper-
ating conditions, including— 

(1) The sudden failure of the critical 

engine; 

(2) For airplanes with three or more 

engines, the sudden failure of the sec-
ond critical engine when the airplane is 
in the en route, approach, or landing 
configuration and is trimmed with the 
critical engine inoperative; and 

(3) Configuration changes, including 

deployment or retraction of decelera-
tion devices. 

(c) The airplane must be shown to be 

safely controllable and maneuverable 
with the most critical of the ice accre-
tion(s) appropriate to the phase of 
flight as defined in Appendices C and O 
of this part, as applicable, in accord-
ance with § 25.21(g), and with the crit-
ical engine inoperative and its pro-
peller (if applicable) in the minimum 
drag position: 

(1) At the minimum V

2

for takeoff; 

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