Figure 12-2.–Nose gear up cycle schematic.
When the landing gear handle is in the UP position,
a circuit is completed from the landing gear handle
circuit breaker, through the landing gear up switch, to
the selector valve. The selector valve is electrically
positioned to direct pressure into the landing gear up
lines and to vent the down lines to return. Fluid flows
from the selector valve, through a flow reguIator to the
up side of the nose gear cylinder. Fluid also flows
through another flow regulator to the down lock
cylinder. The down lock cylinder disengages the down
lock, and the nose gear cylinder starts to raise the nose
gear. As the gear is raised, the nose gear doors are closed
by mechanical linkage. When the gear is fully retracted,
the up lock mechanism engages the nose gear to lock it
in the up position. The up lock mechanism is
mechanically actuated through linkage connected to the
nose gear.
As soon as the down lock mechanism is disengaged
and the gear starts to retract, the pilot’s position indicator
displays change from a wheel to a barber pole, and the
transition light on the landing gear control panel comes
on. As soon as the gear is up and locked, the transition
12-3
