Month in the Patent Office

In order that the pilot shall not be forced to look downwards to consult his instruments during alighting, especially in the case of an aircraft landing upon an aircraft carrier when the pilot would be obliged to look away from the batsman, an image of an instrument such as an airspeed indicator or stall warning indicator D is projected on to the windscreen E and reflected along the pilot's line of vision FG. In the arrangement shown a beam of light from a lamp A is projected through the translucent dial B of the instrument and through a collimating lens system C so that the image is projected at an infinite focus and the pilot thus avoids having to alter the focal distance of his vision.