73-30-00  INDICATING Back

A. System Function

The function of the indicating system is to give indication, in the flight compartment, to show that:

• Rate of the fuel-flow to the engines
• Fuel temperature
• Fuel pressure

The system also gives warnings, in the flight compartment, when:

• The fuel temperature is low
• The fuel pressure is low
• A blockage of the fuel filter is possible

System Operation

• The fuel-flow transmitter (Ref. Fig. 1) measures the rate of the fuel flow, to the left and the right engines, at the engine fuel-control outlet.


• The fuel-filter blockage pressure-switch (Ref. Fig. 1) sends a signal when a differential pressure of more than 8+/- 1 psig is sensed. This gives a warning that the fuel filter will become blocked.


• The fuel low-temperature switch (Ref. Fig. 1) sends a signal when the fuel temperature is less than 35o F. This gives a warning that the fuel heater is unserviceable.


• The fuel low-pressure switch (Ref. Fig. 1) sends a signal when the fuel pressure is less than 12 +/- 1 psig. This gives a warning that the fuel pressure is low.


• The fuel pressure transducer (Ref. Fig. 1) sends a signal when a change in the fuel pressure is sensed. This gives the correct fuel pressure indication.