What position must the XFER switch be set to for fuel transfer?

For fuel transfer to occur, the XFER switch must be set to the "OPEN" position. This setting allows the fuel to flow from one tank to another or facilitate the transfer process within the aircraft’s fuel system.

When the XFER switch is in the "OPEN" position, it closes the circuit needed to activate pumps or valves that are responsible for moving fuel. This is essential for proper operation and safe management of fuel levels during a flight.

Using the other settings, such as OFF, CLOSE, or ON might not allow the transfer process to happen appropriately. This would disrupt the intended operation of the fuel transfer system, leading to potential issues related to fuel management while airborne. Therefore, positioning the switch to OPEN is crucial for enabling the fuel transfer correctly.