SERVICE MANUAL & ICA
WIPLINE 2100 & 2350 FLOATS
Page 22
Revision N
P/N 1002549
Retraction and extension of the main and nose landing gear is effected by a hydraulic actuation system shown
schematically in figure 5-1.
The gear system is hydraulically actuated and driven by one reversible electric pump.
A pressure of between 500 psi and 700 psi in the up and down position is maintained in the supply line. When
the pressure falls below 500 psi in the up and down position, the pressure switch activates the pump solenoid,
providing power to the pump. When the pressure reaches 700 psi in the up and down position, the pressure
switch deactivates the solenoid and the pump motor stops. Figure 5-2 shows the electrical schematic of the
system. A check valve on the output side of the pump retains pressure in the system while the pump is off. The
pump has an interval relief valve that directs oil back to the pump reservoir when the line pressure exceeds 800
psi. The system also has an internal relief valve to protect against thermal expansion when line pressure exceeds
1100 psi.
The selection of gear up or gear down is accomplished by a cockpit mounted control panel. Each float gear has
individual indicator lights on the control panel allowing the pilot to confirm that each gear has fully retracted or
extended.
At the top of each float deck just forward of the step, a visual indicator is provided for the main gear. Nose gear up
and down may be determined visually for position.
An emergency hand pump is provided in case of total electric pump failure or loss of fluid. The reservoir has
additional hydraulic fluid available only to the hand pump.
The main gear has an over-center lock in both up and down positions. Retraction takes place when pressure is
exerted on the actuator piston driving the actuating arm along the slide track (see Figure 5-3). A reverse process
effects extension. Gear position light proximity switches are closed when the cylinder piston (containing the
magnetic material) is adjacent to the switch.
The nose gear has an over-center down lock. Retraction occurs when pressure is applied to the forward fact
of the actuator piston and the carriage is drawn along the tracks in the nose box as shown in Figure 5-4. Gear
position light proximity switches are closed when the piston containing the magnetic material has reached either
end of its travel.
5.1 DESCRIPTION AND OPERATION
Adjustment of the hydraulic actuator stroke is provided at the ends of the piston rods on the nose and main gear.
Nose:
The “gear down” position is set by adjusting the cylinder rod end so the over-center knuckle (brass) rollers bottom
out in the Nose Fork Tracks without preload on the cylinder rod.
The gear up position does not require adjusting as long as the Up Stop has engaged the Up Stop Pin.
5.2 ADJUSTMENT/TEST
