THRUSH AIRCRAFT, INC – MODEL S2R-R1340
AIRCRAFT MAINTENANCE MANUAL
Effective: 01/01/08
8-9
Figure 8-3: Left Instrument Panel
MISCELLANEOUS
INSTRUMENTS
Ref. Figures 8-3 & 8-4
FUEL QUANTITY INDICATOR
A fuel quantity indicator registers the
amount of fuel in either the left or right
tank, up to a maximum of 59 U.S.
gallons. Fuel from 59 to 66.5 U.S.
gallons is un-gaugeable. The indicator
is basically a mili-voltmeter that receives
input signals from the fuel quantity
sensor (liquid level sensors). The liquid
level sensors are float operated variable
resistance transducers, one installed in
each tank. The face of the fuel quantity
indicator is marked in increments from
empty to 59 gallons. The full tank
position of the transducer float produces
a minimum resistance through the
transducer, permitting maximum current
flow through the fuel quantity indicator
and maximum pointer deflection. As the
fuel level of the tank is lowered, the float
repositions a contactor along a
resistance coil inside the transducer,
increasing resistance and thus reducing
current flow through the fuel quantity
indicator. Fuel quantity indicator needle
deflection is proportional to current flow
through. The fuel quantity indicating
system is calibrated prior to leaving the
factory, but should be re-calibrated if
there are any indications of inaccurate
fuel level readings. Calibration can be
done as outlined in Section 5.
VOLTMETER
A voltmeter displays electrical system
voltage when the master switch is on
and allows the pilot to monitor bus bar
voltage. Normal voltmeter readings
must be within the green arc (24.0 to
30.5 volts). Insufficient voltage or
overcharging is indicated by a lower red
