2-3. USE OF OPERATOR'S CONTROLS AND INDICATORS.
The Ground Handling Wheels Assembly controls and indicators are used as described below
2-3.1. Hydraulic Hand Pump Handle Use. The hydraulic hand pump will function in the horizontal, vertical, or any
intermediate position of the Ground Handling Wheels Assembly. The pressure control valve must be closed by turning
the pressure release knob before operating the pump handle. The pump handle operates the pump piston to produce
pressure and move a volume of fluid to the hydraulic rams. The rams extend and mechanically rotate the eccentric
axles to lift the helicopter.
Ensure that no personnel or obstructions are under helicopter skids prior to lowering. Do not
attempt to use the pressure release knob to control descent of the helicopter. Personnel
Injury or equipment damage may occur if the metering valve, which controls the rate of
descent, is not activated. Never operate the hydraulic pump If the metering valve Is not
Installed in the pump outlet.
2-3.2. Hydraulic Pressure Control Valve Knob Use. The pressure release knob is part of the pressure control valve
In the pump body. The control valve must be closed when pumping up pressure to lift the helicopter, and must be
opened to lower the helicopter. The control valve pressure release knob must be rapidly turned to ensure proper
operation of the metering valve. Refer to figure 2-2.
A spring holds the poppet open to provide unrestricted flow of hydraulic fluid, while installing a Ground
Handling Wheels Assembly on a helicopter.
To raise the helicopter, turn the pressure control valve knob clockwise, to the closed(seated) position.
Work the pump handle up and down to build hydraulic pressure. This extends the two hydraulic rams,
which rotate the eccentric axles and raise the helicopter
To lower the helicopter, release the hydraulic pressure by opening the control valve. This is done by
rapidly turning the control valve knob counter clockwise, to the full open position.
2-3.3. Hydraulic Pressure Metering Valve Use. The metering valve Is installed in the pump outlet, to restrict the flow
of hydraulic fluid from the rams to the pump when pressure is released. This ensures that the helicopter is lowered at a
slow and safe rate. The pressure release knob must be rapidly turned to ensure proper operation of the metering valve.
Refer to figure 2-2.
2-3 4. Quick Release Pin Use, Model 204 050-200-5. Procedures for engaging and disengaging the quick release pin
are presented. Refer to figure 2-3
a. Engage Quick Release Pin. Engage the quick release pin as follows:
Position the wheels assembly over the lifting lugs on the helicopter skid and guide fixed nose pin into the
rear lifting lug.
Rotate the cradle downward until the other lifting lug engages the support pin and snaps into position.