Cessna 402C - Page 224

SECTION 7
AIRPLANE & SYSTEMS DESCRIPTIONS
LANDING GEAR WARNING HORN
'MoiL402C
The landing gear warning horn is controlled by the throttles and the
wing flap position. The warning horn will sound intermittently if either
throttle is retarded below approximately 13.0 inches Hg. manifold pressure
with the landing gear retracted or if the wing flaps are lowered past the
15° position with the landing gear in any position except extended and
locked. The warning horn can be activated by either the wing flap position
switch or by throttle position as each functions independently of the
other. The warning horn is also connected to the UP position of the land-
ing gear position switch and will sound if the switch is placed in the UP
position while the airplane is on the ground. The system can be checked by
activating the PRESS-TO-TEST button, see Figure 7-3, located near the
annunciator panel while retarding one throttle at a time. Also, lowering
the wing flaps past the 15° position with the PRESS-TO-TEST button acti-
vated will cause the landing gear warning horn to sound.
LANDING GEAR EMERGENCY EXTENSION SYSTEM
The landing gear emergency extension system, see Figure 7-15, consists
of a red emergency gear extension T-handle, a blowdown bottle, located in
the nose baggage compartment, and associated plu:nbing. The procedure for
emergency gear extension is given in Section 3. Pulling the emergency
control releases dry nitrogen under pres su re into the shut t 1e valve. cau s-
ing the shuttle valve to move from the hydraulic to the air position. The
nitrogen then flows into the uplocks which releases the gear to the free-
fall position. and then into the landing gear cylinders. which drives the
landing gear into the down and locked position •
.... NOTE --.
The landing gear cannot be retracted after ener~ency
gear extension until the system has been ground
serviced.
LANDING GEAR SHOCK STRUTS
Shock absorption is provided on each gear by an air-aver-oil shock
strut. This strut is composed of two basic parts: an upper barrel assem-
bly and an inner tube assembly which fits inside the upper barrel assenbly.
The inner barrel assembly contains an orifice and tapered metering pin
which vary the resistance to shock according to severity transmitted to the
upper barrel assembly.
FUEL SYSTEM
The fuel system, see Figure 7-16. consists of two main tanks. two fuel
selectors, emergency crossfeed shutoff valves and necessary components to
complete the system.
MAIN TANKS
The main fuel tanks are an integral portion of the sealed wet win~.
These tanks supply their respective engine with fuel for norElal operations,
including takeoffs and landings. An auxiliary fuel pump, located outside
the tank. provides fuel pressure for priming during en'gine start. In the
• _ AA
1 November 1979