Fuel Indicating

The fuel indicating system provides the indication of the fuel level and the signal to warn of a low fuel condition. It consists of the fuel lever sensor.

The fuel level sensor combines the fuel level and the low fuel warning functions into a single unit. The fuel level probe is a tube that is inserted in the center of the fuel cell, from the top to the bottom. An electronic circuit at the top of the fuel level probe measures the fuel level from the capacitive sensor and sends the signal to the engine and airframe interface unit (GEA). The low level sensor is an electronic circuit attached at a specified height to the side of the fuel level probe. It is a solid state sensor and provides the low level signal to the integrated avionics unit (GIA).

Operation

The fuel level sensor is energized with 28 VDC from the main bus.

The fuel level probe can be isolated with the FUEL circuit breaker. The low level sensor can be isolated with the FUEL LEVEL circuit breaker.

The fuel level probe and low level sensor circuits are grounded to the helicopter structure. The fuel level sensor is also bonded to the helicopter structure.

The fuel level sensor provide a voltage proportional to the fuel level to the engine and airframe interface unit (GEA).

When the fuel level gets below approximately 11.02 +/- 1.46 U.S. gallons (41.6 +/- 5.52 liters), the low level sensor provides a ground to the integrated avionics unit (GIA) and to the fuel low relay. Refer to Engine Control for details about the fuel low relay.