Coupling aircraft electric power supply to load

A method of operation is provided during which a pre-charge switch is closed to electrically couple a power supply to a motor controller through a pre-charge supply circuit, where a main switch is open. An electrical parameter of electricity directed through the pre-charge supply circuit is measured when the pre-charge switch is closed and the main switch is open. The main switch is closed to electrically couple the power supply to the motor controller through the main supply circuit when the electrical parameter is equal to or passes a threshold.