FSD International
Commander 115 TC
Pilot Operating Handbook
- 52 –
Copyright© 2008 by FSD International. All rights reserved.
For use with Microsoft Flight Simulator only. Not to be used for real-world aviation.
FUEL QUANTITY INDICATOR
The fuel quantity indicating system consists of a dual fuel quantity indicator located on the engine
instrument sub-panel, electrically connected to the fuel quantity transmitters installed in each fuel
tank. The fuel quantity indicating circuit is equipped with two damping resistors within the
transmitter. These resistors dampen indicator needle oscillations, caused by irregular movement of
the transmitter float, during flight through rough air. The fuel quantity transmitters and indicators
have been calibrated at the factory and should not require recalibration; however, if the system
does require recalibration, this should be done by a licensed A& P mechanic in accord with the
current Maintenance Manual.
Ungaugeable fuel begins at 28 gallons. The battery and/or alternator master switches must be ON
for the fuel quantity indicator to function.
6.12 HYDRAULIC SYSTEMS
LANDING GEAR EXTENSION/RETRACTION SYSTEM
The hydraulic power supply is an integrated hydraulic pack containing a reversible, electric motor
driven hydraulic pump, a reservoir, pressure control valves, a thermal relief valve and a gear up
check valve. The power pack is located in the left forward area of the fuselage tail cone and is
accessible through the left aft baggage compartment panel. The sale function of the hydraulic
power pack is to raise and lower the tricycle landing gear.
When the landing gear selector switch is pulled out slightly to clear the detent and placed in the UP
position, hydraulic fluid, under pressure, is directed to the UP side of the landing gear actuators,
causing the gear to start to retract. Fluid on the DOWN side of the actuator flows back to the
reservoir. Movement of the gear from the DOWN and LOCKED position deactivates a down position
switch, located on each gear drag link, causing the three gear DOWN and LOCKED lights to
extinguish, illuminating the red GEAR WARNING light. As each gear is fully retracted, it activates a
gear up position switch, and when all three gear up switches have activated the GEAR WARNING
light extinguishes. A pressure switch, located in the UP hydraulic line, actuates when the pressure
in the line reaches 150 (± 50) PSI and shuts off the hydraulic pack motor. A gear up check valve in
the return line to the hydraulic pack closes, trapping pressure in the line, causing a hydraulic lock
which holds the gear up. A loss of 250 PSI of pressure in the UP line will be sensed by the pressure
switch, which will allow the hydraulic pump to run and build the pressure back up the 1650 (±50)
PSI.
Placing the gear selector switch in the DOWN position, directs hydraulic fluid to the down side of
the actuator. Fluid in the UP line flows back to the reservoir and the gear extends. As the gear
starts down, the up position switches deactivate and the GEAR WARNING light illuminates. When
the gear is fully extended with the drag links over center, the down position switches activate,
illuminating the three green DOWN and LOCKED lights, and the red GEAR WARNING light
extinguishes. A pressure switch in the down line shuts off the hydraulic pack when pressure in the
line reaches 500 (±SO) PSI. A "pilot" check valve in the down line closes. trapping hydraulic
pressure, locking the gear down with a hydraulic lock in the down line, plus a mechanical over
center lock. If anyone of the three down position switches fails to actuate when the gear is fully
extended. that gears corresponding green light will not illuminate, the GEAR WARNING light will
remain illuminated. the down pressure switch will be bypassed electrically, and the hydraulic pump
will continue to operate.
