Abstract: The present invention is a folding protective cover primarily for openings which are generally circular in shape, particularly the air inlet and exhaust ducts of a stopped turbo-engine as used by aircraft. The invention is comprised of a generally circular ring shaped frame which is made up of four arc shaped sections of approximately 90 degrees each. Three hinges are mounted between the sections in such a manner that the frame may be folded into an arc of approximately 90 degrees. Affixed to the outer edge of the frame is a resilient gasket and affixed across the center of the frame is a waterproof fabric panel.