207 

Federal Aviation Administration, DOT 

§ 25.25 

(2) Each requirement of this subpart, 

except §§ 25.121(a), 25.123(c), 25.143(b)(1) 
and (2), 25.149, 25.201(c)(2), 25.239, and 
25.251(b) through (e), must be met in 
the icing conditions specified in Appen-
dix C of this part. Section 25.207(c) and 
(d) must be met in the landing configu-
ration in the icing conditions specified 
in Appendix C, but need not be met for 
other configurations. Compliance must 
be shown using the ice accretions de-
fined in part II of Appendix C of this 
part, assuming normal operation of the 
airplane and its ice protection system 
in accordance with the operating limi-
tations and operating procedures estab-
lished by the applicant and provided in 
the airplane flight manual. 

(3) If the applicant does not seek cer-

tification for flight in all icing condi-
tions defined in Appendix O of this 
part, each requirement of this subpart, 
except §§ 25.105, 25.107, 25.109, 25.111, 
25.113, 25.115, 25.121, 25.123, 25.143(b)(1), 
(b)(2), and (c)(1), 25.149, 25.201(c)(2), 
25.207(c), (d), and (e)(1), 25.239, and 
25.251(b) through (e), must be met in 
the Appendix O icing conditions for 
which certification is not sought in 
order to allow a safe exit from those 
conditions. Compliance must be shown 
using the ice accretions defined in part 
II, paragraphs (b) and (d) of Appendix 
O, assuming normal operation of the 
airplane and its ice protection system 
in accordance with the operating limi-
tations and operating procedures estab-
lished by the applicant and provided in 
the airplane flight manual. 

(4) If the applicant seeks certifi-

cation for flight in any portion of the 
icing conditions of Appendix O of this 
part, each requirement of this subpart, 
except §§ 25.121(a), 25.123(c), 25.143(b)(1) 
and (2), 25.149, 25.201(c)(2), 25.239, and 
25.251(b) through (e), must be met in 
the Appendix O icing conditions for 
which certification is sought. Section 
25.207(c) and (d) must be met in the 
landing configuration in the Appendix 
O icing conditions for which certifi-
cation is sought, but need not be met 
for other configurations. Compliance 
must be shown using the ice accretions 
defined in part II, paragraphs (c) and 
(d) of Appendix O, assuming normal op-
eration of the airplane and its ice pro-
tection system in accordance with the 
operating limitations and operating 

procedures established by the applicant 
and provided in the airplane flight 
manual. 

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as 
amended by Amdt. 25–23, 35 FR 5671, Apr. 8, 
1970; Amdt. 25–42, 43 FR 2320, Jan. 16, 1978; 
Amdt. 25–72, 55 FR 29774, July 20, 1990; Amdt. 
25–121, 72 FR 44665, Aug. 8, 2007 Amdt. 25–135, 
76 FR 74654, Dec. 1, 2011; Amdt. 25–140, 79 FR 
65524, Nov. 4, 2014] 

§ 25.23

Load distribution limits. 

(a) Ranges of weights and centers of 

gravity within which the airplane may 
be safely operated must be established. 
If a weight and center of gravity com-
bination is allowable only within cer-
tain load distribution limits (such as 
spanwise) that could be inadvertently 
exceeded, these limits and the cor-
responding weight and center of grav-
ity combinations must be established. 

(b) The load distribution limits may 

not exceed— 

(1) The selected limits; 
(2) The limits at which the structure 

is proven; or 

(3) The limits at which compliance 

with each applicable flight require-
ment of this subpart is shown. 

§ 25.25

Weight limits. 

(a) 

Maximum weights. 

Maximum 

weights corresponding to the airplane 
operating conditions (such as ramp, 
ground or water taxi, takeoff, en route, 
and landing), environmental conditions 
(such as altitude and temperature), and 
loading conditions (such as zero fuel 
weight, center of gravity position and 
weight distribution) must be estab-
lished so that they are not more than— 

(1) The highest weight selected by 

the applicant for the particular condi-
tions; or 

(2) The highest weight at which com-

pliance with each applicable structural 
loading and flight requirement is 
shown, except that for airplanes 
equipped with standby power rocket 
engines the maximum weight must not 
be more than the highest weight estab-
lished in accordance with appendix E of 
this part; or 

(3) The highest weight at which com-

pliance is shown with the certification 
requirements of Part 36 of this chapter. 

(b) 

Minimum weight. 

The minimum 

weight (the lowest weight at which 

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