WIPLINE MODEL 8000 SERVICE MANUAL
Page 16 of 62
1002554 • Rev H
4.0 AMPHIBIAN LANDING GEAR SYSTEM OPERATION & MAINTENANCE
The landing gear incorporated within the amphibious floats on this airplane is
retractable, quadricycle type with two swiveling nose (or bow) wheels and four (4) (two
(2) sets of dual) main wheels. Air-oil shock struts on the two main landing gear
assemblies provide shock absorption.
The main landing gear has dual 6:00 x 6 8-ply type III tires and the nose landing
gear has one 5:00 x 5 10-ply tire. The gear system is hydraulically actuated and
driven by two hydraulic pumps. Brakes are hydraulic and have a caliper on each main
wheel.
Steering on land is accomplished by differential braking. The nose wheels are full
castering.
Landing gear extension and retraction is accomplished by two (2) electrically-
driven hydraulic pumps and four (4) hydraulic actuators (one (1) for each gear). The
hydraulic pumps are located in fuselage aft of cockpit and the hydraulic actuators are
located adjacent to each gear. Hydraulic system fluid level should be checked
periodically by viewing the sight glass for fluid level in the upper one-third of the range.
If fluid is low, fill with MIL-H-5606 or equivalent. Filters are installed on pickup tube
inside of hydraulic reservoirs. Clean every 100 hours.
Landing gear operation is initiated by movement of the landing gear handle.
When the handle is repositioned, hydraulic pressure in the system will drop and
pressure switches will automatically turn on the hydraulic pump motors to maintain
operating pressure in the system. When the gear cycle is completed, the pump will
automatically shut off. If the pressure in the system drops to a preset value, the
pressure switches turn the pump motors back on and build up the pressure to the limit
again. Eight (8) position-indicator lights four (4) gear UP and four (4) gear DOWN are
provided to show landing gear position. Two (2) additional indicator lights show when
the landing gear pump motors are operating.
4.1 LANDING GEAR HANDLE
The landing gear handle controls a hydraulic selector valve within the selector
head in the instrument panel and has two (2) positions (UP and DOWN LAND) which
give a mechanical indication of the gear position selected. From either position, the
handle must be pulled out to clear a detent before it can be repositioned.
4.2 INDICATOR LIGHTS
Ten (10) indicator lights are mounted on the landing gear control unit adjacent to
the landing gear handle. Four (4) blue indicator lights, labeled NOSE and MAIN (left-
hand lights for the left float and right-hand lights for the right float), show by their
illumination that the landing gear is up and locked. The four (4) amber indicator lights,
labeled NOSE and MAIN (left-hand lights for the let float and right-hand lights
