217 

Federal Aviation Administration, DOT 

§ 25.125 

(d) 

Approach.  In a configuration cor-

responding to the normal all-engines- 
operating procedure in which V

SR

for 

this configuration does not exceed 110 
percent of the V

SR

for the related all- 

engines-operating landing configura-
tion: 

(1) The steady gradient of climb may 

not be less than 2.1 percent for two-en-
gine airplanes, 2.4 percent for three-en-
gine airplanes, and 2.7 percent for four- 
engine airplanes, with— 

(i) The critical engine inoperative, 

the remaining engines at the go-around 
power or thrust setting; 

(ii) The maximum landing weight; 
(iii) A climb speed established in con-

nection with normal landing proce-
dures, but not exceeding 1.4 V

SR

; and 

(iv) Landing gear retracted. 
(2) The requirements of paragraph 

(d)(1) of this section must be met: 

(i) In non-icing conditions; and 
(ii) In icing conditions with the most 

critical of the approach ice accretion(s) 
defined in Appendices C and O of this 
part, as applicable, in accordance with 
§ 25.21(g). The climb speed selected for 
non-icing conditions may be used if the 
climb speed for icing conditions, com-
puted in accordance with paragraph 
(d)(1)(iii) of this section, does not ex-
ceed that for non-icing conditions by 
more than the greater of 3 knots CAS 
or 3 percent. 

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as 
amended by Amdt. 25–84, 60 FR 30749, June 9, 
1995; Amdt. 25–108, 67 FR 70826, Nov. 26, 2002; 
Amdt. 25–121, 72 FR 44666; Aug. 8, 2007; Amdt. 
25–140, 79 FR 65525, Nov. 4, 2014] 

§ 25.123

En route flight paths. 

(a) For the en route configuration, 

the flight paths prescribed in para-
graph (b) and (c) of this section must 
be determined at each weight, altitude, 
and ambient temperature, within the 
operating limits established for the 
airplane. The variation of weight along 
the flight path, accounting for the pro-
gressive consumption of fuel and oil by 
the operating engines, may be included 
in the computation. The flight paths 
must be determined at a speed not less 
than V

FTO

, with— 

(1) The most unfavorable center of 

gravity; 

(2) The critical engines inoperative; 

(3) The remaining engines at the 

available maximum continuous power 
or thrust; and 

(4) The means for controlling the en-

gine-cooling air supply in the position 
that provides adequate cooling in the 
hot-day condition. 

(b) The one-engine-inoperative net 

flight path data must represent the ac-
tual climb performance diminished by 
a gradient of climb of 1.1 percent for 
two-engine airplanes, 1.4 percent for 
three-engine airplanes, and 1.6 percent 
for four-engine airplanes— 

(1) In non-icing conditions; and 
(2) In icing conditions with the most 

critical of the en route ice accretion(s) 
defined in Appendices C and O of this 
part, as applicable, in accordance with 
§ 25.21(g), if: 

(i) A speed of 1.18 ‘‘V

SR0

with the en 

route ice accretion exceeds the en 
route speed selected for non-icing con-
ditions by more than the greater of 3 
knots CAS or 3 percent of V

SR

; or 

(ii) The degradation of the gradient 

of climb is greater than one-half of the 
applicable actual-to-net flight path re-
duction defined in paragraph (b) of this 
section. 

(c) For three- or four-engine air-

planes, the two-engine-inoperative net 
flight path data must represent the ac-
tual climb performance diminished by 
a gradient of climb of 0.3 percent for 
three-engine airplanes and 0.5 percent 
for four-engine airplanes. 

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as 
amended by Amdt. 25–121, 72 FR 44666; Aug. 8, 
2007; Amdt. 25–140, 79 FR 65525, Nov. 4, 2014] 

§ 25.125

Landing. 

(a) The horizontal distance necessary 

to land and to come to a complete stop 
(or to a speed of approximately 3 knots 
for water landings) from a point 50 feet 
above the landing surface must be de-
termined (for standard temperatures, 
at each weight, altitude, and wind 
within the operational limits estab-
lished by the applicant for the air-
plane): 

(1) In non-icing conditions; and 
(2) 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), if V

REF

for icing conditions ex-

ceeds V

REF

for non-icing conditions by 

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