209 

Federal Aviation Administration, DOT 

§ 23.302 

(c) Except as provided in paragraphs 

(d) and (e) of this section, compliance 
with the provisions of paragraph (a) of 
this section must be demonstrated in 
flight over the acceleration range as 
follows: 

(1) ¥1 g to +2.5 g; or 
(2) 0 g to 2.0 g, and extrapolating by 

an acceptable method to ¥1 g and +2.5 
g. 

(d) If the procedure set forth in para-

graph (c)(2) of this section is used to 
demonstrate compliance and marginal 
conditions exist during flight test with 
regard to reversal of primary longitu-
dinal control force, flight tests must be 
accomplished from the normal accel-
eration at which a marginal condition 
is found to exist to the applicable limit 
specified in paragraph (b)(1) of this sec-
tion. 

(e) During flight tests required by 

paragraph (a) of this section, the limit 
maneuvering load factors, prescribed in 
§§ 23.333(b) and 23.337, need not be ex-
ceeded. In addition, the entry speeds 
for flight test demonstrations at nor-
mal acceleration values less than 1 g 
must be limited to the extent nec-
essary to accomplish a recovery with-
out exceeding V

DF

/M

DF

. 

(f) In the out-of-trim condition speci-

fied in paragraph (a) of this section, it 
must be possible from an overspeed 
condition at V

DF

/M

DF

to produce at 

least 1.5 g for recovery by applying not 
more than 125 pounds of longitudinal 
control force using either the primary 
longitudinal control alone or the pri-
mary longitudinal control and the lon-
gitudinal trim system. If the longitu-
dinal trim is used to assist in pro-
ducing the required load factor, it must 
be shown at V

DF

/M

DF

that the longitu-

dinal trim can be actuated in the air-
plane nose-up direction with the pri-
mary surface loaded to correspond to 
the least of the following airplane 
nose-up control forces: 

(1) The maximum control forces ex-

pected in service, as specified in 
§§ 23.301 and 23.397. 

(2) The control force required to 

produce 1.5 g. 

(3) The control force corresponding to 

buffeting or other phenomena of such 
intensity that it is a strong deterrent 

to further application of primary longi-
tudinal control force. 

[Doc. No. FAA–2009–0738, 76 FR 75755, Dec. 2, 
2011] 

Subpart C—Structure 

G

ENERAL

 

§ 23.301

Loads. 

(a) Strength requirements are speci-

fied in terms of limit loads (the max-
imum loads to be expected in service) 
and ultimate loads (limit loads multi-
plied by prescribed factors of safety). 
Unless otherwise provided, prescribed 
loads are limit loads. 

(b) Unless otherwise provided, the 

air, ground, and water loads must be 
placed in equilibrium with inertia 
forces, considering each item of mass 
in the airplane. These loads must be 
distributed to conservatively approxi-
mate or closely represent actual condi-
tions. Methods used to determine load 
intensities and distribution on canard 
and tandem wing configurations must 
be validated by flight test measure-
ment unless the methods used for de-
termining those loading conditions are 
shown to be reliable or conservative on 
the configuration under consideration. 

(c) If deflections under load would 

significantly change the distribution of 
external or internal loads, this redis-
tribution must be taken into account. 

(d) Simplified structural design cri-

teria may be used if they result in de-
sign loads not less than those pre-
scribed in §§ 23.331 through 23.521. For 
airplane configurations described in 
appendix A, § 23.1, the design criteria of 
appendix A of this part are an approved 
equivalent of §§ 23.321 through 23.459. If 
appendix A of this part is used, the en-
tire appendix must be substituted for 
the corresponding sections of this part. 

[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964; 30 
FR 258, Jan. 9, 1965, as amended by Amdt. 23– 
28, 47 FR 13315, Mar. 29, 1982; Amdt. 23–42, 56 
FR 352, Jan. 3, 1991; Amdt. 23–48, 61 FR 5143, 
Feb. 9, 1996] 

§ 23.302

Canard or tandem wing con-

figurations. 

The forward structure of a canard or 

tandem wing configuration must: 

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