When the switch is set to UNLOCK, the control valve
on the module is de-energized. Hydraulic pressure is
removed from the upper port of the actuator and applied
to the lower port. The piston within the swivel housing is
moved upward, releasing the swivel lock from the detent
and allowing the wheel to swivel freely.
NO BREAK - WORK HARDER
Setting the switch to UNLOCK also disengages the
heading hold circuitry in both AFCS computers to allow
the helicopter to be steered in different directions. The
swivel locks are spring-loaded up. Therefore, when the
hydraulic system is shut down, the locks are disengaged
and the wheel is free to caster.
Setting the SWIVEL switch to STEER applies power to
the power steering solenoid valve on the control module,
the power steering control box power supply, and an
out-of-phase switch on the aft right landing gear.