The fuel temperature and indicating system measures the fuel temperature and supplies visual indication of the temperature on the overhead panel, P5. The system has a fuel tank sensor and a temperature indicator. Power is supplied to the system by the 28 volt dc left bus. Information displayed is used in conjunction with the fuel de-icing system when it may be advisable to use the fuel heater to prevent fuel icing at the fuel filter.
The sensor and lead resistance form two legs of an input bridge circuit. The resulting signal from the bridge circuit is amplified, converted from analog to digital, and shown as a digital readout.To do a test of the fuel temperature indicator, put the fuel quantity test switch on the P61 panel to FUEL QTY. The readout should show -185+/-2.