Abstract: A thick panel is provided constructed of resilient deformable material and of a plan, size and shape to be snugly received in an airframe opening formed by the removal of an airframe stress panel. The resilient panel is positionable within the airframe opening in a manner fully closing the latter against the entrance of foreign material into the interior of the airframe from the exterior thereof. The thick panel includes an outer surface provided with a peripheral rabbet formed therein whereby the outer margin of the thick panel may be received beneath the airframe outer skin portions disposed about and defining the opening in which the thick panel is received. Further, the outer surface of the thick panel includes a flexible coating of substantially fluid impervious material.