247 

Federal Aviation Administration, DOT 

§ 23.735 

there is a manual shutoff for the warn-
ing device prescribed in this paragraph, 
the warning system must be designed 
so that when the warning has been sus-
pended after one or more throttles are 
closed, subsequent retardation of any 
throttle to, or beyond, the position for 
normal landing approach will activate 
the warning device. 

(2) A device that functions continu-

ously when the wing flaps are extended 
beyond the maximum approach flap po-
sition, using a normal landing proce-
dure, if the landing gear is not fully ex-
tended and locked. There may not be a 
manual shutoff for this warning device. 
The flap position sensing unit may be 
installed at any suitable location. The 
system for this device may use any 
part of the system (including the aural 
warning device) for the device required 
in paragraph (f)(1) of this section. 

(g) 

Equipment located in the landing 

gear bay. If the landing gear bay is used 
as the location for equipment other 
than the landing gear, that equipment 
must be designed and installed to mini-
mize damage from items such as a tire 
burst, or rocks, water, and slush that 
may enter the landing gear bay. 

[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as 
amended by Amdt. 23–7, 34 FR 13091, Aug. 13, 
1969; Amdt. 23–21, 43 FR 2318, Jan. 1978; Amdt. 
23–26, 45 FR 60171, Sept. 11, 1980; Amdt. 23–45, 
58 FR 42164, Aug. 6, 1993; Amdt. 23–49, 61 FR 
5166, Feb. 9, 1996] 

§ 23.731

Wheels. 

(a) The maximum static load rating 

of each wheel may not be less than the 
corresponding static ground reaction 
with— 

(1) Design maximum weight; and 
(2) Critical center of gravity. 
(b) The maximum limit load rating of 

each wheel must equal or exceed the 
maximum radial limit load determined 
under the applicable ground load re-
quirements of this part. 

[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as 
amended by Amdt. 23–45, 58 FR 42165, Aug. 6, 
1993] 

§ 23.733

Tires. 

(a) Each landing gear wheel must 

have a tire whose approved tire ratings 
(static and dynamic) are not exceed-
ed— 

(1) By a load on each main wheel tire) 

to be compared to the static rating ap-
proved for such tires) equal to the cor-
responding static ground reaction 
under the design maximum weight and 
critical center of gravity; and 

(2) By a load on nose wheel tires (to 

be compared with the dynamic rating 
approved for such tires) equal to the re-
action obtained at the nose wheel, as-
suming the mass of the airplane to be 
concentrated at the most critical cen-
ter of gravity and exerting a force of 
1.0 W downward and 0.31 W forward 
(where W is the design maximum 
weight), with the reactions distributed 
to the nose and main wheels by the 
principles of statics and with the drag 
reaction at the ground applied only at 
wheels with brakes. 

(b) If specially constructed tires are 

used, the wheels must be plainly and 
conspicuously marked to that effect. 
The markings must include the make, 
size, number of plies, and identification 
marking of the proper tire. 

(c) Each tire installed on a retract-

able landing gear system must, at the 
maximum size of the tire type expected 
in service, have a clearance to sur-
rounding structure and systems that is 
adequate to prevent contact between 
the tire and any part of the structure 
of systems. 

[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as 
amended by Amdt. 23–7, 34 FR 13092, Aug. 13, 
1969; Amdt. 23–17, 41 FR 55464, Dec. 20, 1976; 
Amdt. 23–45, 58 FR 42165, Aug. 6, 1993] 

§ 23.735

Brakes. 

(a) Brakes must be provided. The 

landing brake kinetic energy capacity 
rating of each main wheel brake assem-
bly must not be less than the kinetic 
energy absorption requirements deter-
mined under either of the following 
methods: 

(1) The brake kinetic energy absorp-

tion requirements must be based on a 
conservative rational analysis of the 
sequence of events expected during 
landing at the design landing weight. 

(2) Instead of a rational analysis, the 

kinetic energy absorption require-
ments for each main wheel brake as-
sembly may be derived from the fol-
lowing formula: 

KE=0.0443 WV

2

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