An unloading conveyor swing control system including an unloading conveyor fitted to a self-propelled harvesting machine such as a combine harvester. The conveyor is moveable around a pivot axis through a movement range between a first, stowed, position and a second position. An actuator is connected to the conveyor and arranged to move the conveyor throughout the movement range. A sensor is configured to sense an angular position of the conveyor within the movement range and generate a representative position signal. A user interface device is provided for receiving user-commands to move the conveyor. A controller is in communication with the sensor, the actuator and the user interface device. The conveyor is automatically moved into the stowed position in response to said angular position falling below a predetermined threshold angle.
