215 

Federal Aviation Administration, DOT 

§ 23.367 

§ 23.351

Yawing conditions. 

The airplane must be designed for 

yawing loads on the vertical surfaces 
resulting from the loads specified in 
§§ 23.441 through 23.445. 

[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964; 30 
FR 258, Jan. 9, 1965, as amended by Amdt. 23– 
42, 56 FR 352, Jan. 3, 1991] 

§ 23.361

Engine torque. 

(a) Each engine mount and its sup-

porting structure must be designed for 
the effects of— 

(1) A limit engine torque cor-

responding to takeoff power and pro-
peller speed acting simultaneously 
with 75 percent of the limit loads from 
flight condition A of § 23.333(d); 

(2) A limit engine torque cor-

responding to maximum continuous 
power and propeller speed acting si-
multaneously with the limit loads from 
flight condition A of § 23.333(d); and 

(3) For turbopropeller installations, 

in addition to the conditions specified 
in paragraphs (a)(1) and (a)(2) of this 
section, a limit engine torque cor-
responding to takeoff power and pro-
peller speed, multiplied by a factor ac-
counting for propeller control system 
malfunction, including quick feath-
ering, acting simultaneously with lg 
level flight loads. In the absence of a 
rational analysis, a factor of 1.6 must 
be used. 

(b) For turbine engine installations, 

the engine mounts and supporting 
structure must be designed to with-
stand each of the following: 

(1) A limit engine torque load im-

posed by sudden engine stoppage due to 
malfunction or structural failure (such 
as compressor jamming). 

(2) A limit engine torque load im-

posed by the maximum acceleration of 
the engine. 

(c) The limit engine torque to be con-

sidered under paragraph (a) of this sec-
tion must be obtained by multiplying 
the mean torque by a factor of— 

(1) 1.25 for turbopropeller installa-

tions; 

(2) 1.33 for engines with five or more 

cylinders; and 

(3) Two, three, or four, for engines 

with four, three, or two cylinders, re-
spectively. 

[Amdt. 23–26, 45 FR 60171, Sept. 11, 1980, as 
amended by Amdt. 23–45, 58 FR 42160, Aug. 6, 
1993] 

§ 23.363

Side load on engine mount. 

(a) Each engine mount and its sup-

porting structure must be designed for 
a limit load factor in a lateral direc-
tion, for the side load on the engine 
mount, of not less than— 

(1) 1.33, or 
(2) One-third of the limit load factor 

for flight condition A. 

(b) The side load prescribed in para-

graph (a) of this section may be as-
sumed to be independent of other flight 
conditions. 

§ 23.365

Pressurized cabin loads. 

For each pressurized compartment, 

the following apply: 

(a) The airplane structure must be 

strong enough to withstand the flight 
loads combined with pressure differen-
tial loads from zero up to the max-
imum relief valve setting. 

(b) The external pressure distribution 

in flight, and any stress concentra-
tions, must be accounted for. 

(c) If landings may be made with the 

cabin pressurized, landing loads must 
be combined with pressure differential 
loads from zero up to the maximum al-
lowed during landing. 

(d) The airplane structure must be 

strong enough to withstand the pres-
sure differential loads corresponding to 
the maximum relief valve setting mul-
tiplied by a factor of 1.33, omitting 
other loads. 

(e) If a pressurized cabin has two or 

more compartments separated by bulk-
heads or a floor, the primary structure 
must be designed for the effects of sud-
den release of pressure in any compart-
ment with external doors or windows. 
This condition must be investigated for 
the effects of failure of the largest 
opening in the compartment. The ef-
fects of intercompartmental venting 
may be considered. 

§ 23.367

Unsymmetrical loads due to 

engine failure. 

(a) Turbopropeller airplanes must be 

designed for the unsymmetrical loads 

VerDate Mar<15>2010 

10:12 Mar 18, 2014

Jkt 232046

PO 00000

Frm 00225

Fmt 8010

Sfmt 8010

Y:\SGML\232046.XXX

232046

pmangrum on DSK3VPTVN1PROD with CFR