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keeps them aligned with each other.
Shimmy Damper
To reduce nose gear shimmy during takeoff,
landing, and taxiing, the nose gear has a
shimmy damper. It is a friction band around
the center of the shock strut cylinder. It rubs
against the inside of the trunnion using friction
to reduce nosewheel shimmy.
Drag Brace and Downlock
In the down (gear-extended) position, the gear
is mechanically locked down by an integral locking
mechanism in the drag brace. A position
switch on the drag brace signals when the nose
gear is down-and-locked. During extension, the
downlock is spring-actuated to lock mechanically.
During retraction, the downlock is released
by a hydraulic actuator on the drag brace.
Uplock Assembly
A mechanical latching system (uplock hook)
similar to the main gear system is attached to
the airframe in the nose wheel well. It locks
the nose gear in the up (gear-retracted) position.
During gear extension, a fluid
actuator/valve unit releases the hook and then
passes hydraulic fluid (or pressurized nitrogen
in an emergency) to the gear actuator. On
gear retraction, the uplock latch catches a
roller on the rising nosewheel fork to lock the
gear in the up position. (During preflight,
check that the roller rotates.) A switch in the
uplock hook mechanism detects whether or not
the gear is up-and-locked.
Gear Actuator
The fluid-driven nose gear actuator retracts to
extend the nose gear. It also triggers nose gear
door operation through linkages.
Single Wheel and Tire Assembly
The nosewheel assembly includes a wheel and
tire. The nose gear tire has chines to deflect
water and slush. The tire must be inflated to
120 ± 5 psi or 827 KPa (± 34 KPa). Maximum
tire limit speed is 160 knots.
Gear Control Solenoid Valve
The gear control solenoid valve regulates the
flow of hydraulic fluid to the gear actuators, uplock-
release actuators, and nose gear downlock-
release actuator. It is an electrically driven
solenoid valve, actuated by two opposing solenoids
that respond to electrical commands from
the LANDING GEAR handle.
When the LANDING GEAR handle is commanded
DOWN, the gear-extend solenoid on
the valve moves the valve to the gear-extend
position, routing fluid pressure to the uplockrelease
actuators and then to the gear-extend
side of the gear actuators (see Figure 14-4).
When the LANDING GEAR handle is commanded
UP, the gear-retract solenoid on the
valve moves the valve to the gear-retract position,
which routes fluid to the nose gear downlock
release actuator and the gear-retract side
of all three gear actuators (see Figure 14-6).
Without DC power, the valve centers, releasing
pressure from the gear-extend side of the
system. This permits emergency extension of
the gear using mechanical and pneumatic actuation
(see Figure 14-5). DC power can be disconnected
from the gear control solenoid valve
by pulling the LDG GEAR CONTROL circuit
breaker on the SYSTEMS panel of the
left CB panel.
CONTROLS AND INDICATIONS
LANDING GEAR Control
Handle
The LANDING GEAR control handle is on
the left side of the center tilt panel (Figure
14-7) and controls the normal landing gear retraction
and extension procedure. The handle
14-10 510OM-00
CITATION MUSTANG OPERATING MANUAL
actuates switches to complete circuits to the
extend or retract side of the gear control solenoid
valve. The gear handle must be pulled
out of a detent prior to movement to either the
GEAR UP or GEAR DOWN position.
On the ground, to keep the gear handle in the
GEAR DOWN position, the left and right main
gear squat switch deenergizes a locking-solenoid
in the instrument panel to extend a springloaded
plunger into the gear handle path. This
prevents inadvertent movement of the handle
to the GEAR UP position (Figure 14-8).
Airborne, with the left and right main gear
squat switches in the in-flight position, the
landing gear handle locking solenoid energizes
to retract the plunger. This frees the
handle for movement to the GEAR UP position.
This safety feature cannot be overridden.
If the solenoid fails or electrical power
is lost, the gear handle cannot be moved to
the GEAR UP position.
When the gear handle is up, if the locking-solenoid
plunger deenergizes and extends (due
to DC power failure or another cause), the
plunger does not prevent moving the gear handle
to the down position.
Never attempt to pull the gear handle up during
taxi.
　
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