Abstract: A hood preferably made of sheet metal for directing coolant air in air inlet holes in the walls of an avionic box containing electrical components such as an avionic line replaceable unit (LRU). The hood has a top wall with opposite side walls and an end wall that depends unitarily from the top wall. The hood fits onto the box with the top wall and side walls of the hood spaced from the corresponding top wall and side walls, respectively of the avionic box when the hood is mounted on the box to thereby define coolant air conducting passageways contiguous with the box. The end wall of the hood that depends from the top wall is spaced from the end wall of the box when the hood is mounted to the box to define an air distribution plenum that is in communication with the passageways at the sides and top of the box so coolant air is directed through holes in the end wall if any holes are used in the end wall and side walls of the box. The end wall of the hood has an opening for being covered by a door.