Abstract: A display system for enabling a pilot in an aircraft to simultaneously view an image of selected display information and a scene external to the aircraft during low visibility conditions, such as the night-time, is provided. An image intensifier tube is mounted on the side of a pilot's helmet, preferably a Helmet Display system, so that the image sensed coincides with the pilot's field of view. The image intensifier tube intensifies light from the external scene and outputs voltages representative of the scene to a converter. The output voltage is converted to a video signal having a format which is compatible to the display system in use. A Combining Circuit combines the compatible video signal with video signals from other display sources, such as instrumentation panel displays. The combined electrical signals are input to a display driver which drives the display system to cause the selected display information to be superimposed on the external scene viewed by the pilot.