A fuel air heat exchanger for a gas turbine engine having fuel and air conduits in heat exchange relationship with one another, and a distribution conduit in heat exchange relationship with a component to be cooled. The distribution conduit is in fluid communication with the outlet of each air conduit. The heat exchanger also includes a secondary air inlet in fluid communication with the distribution conduit and a flow selection member selectively movable between first and second configurations. In the first configuration, the flow selection member closes the fluid communication between the secondary inlet and the distribution conduit. In the second configuration, the flow selection member opens the fluid communication between the secondary air inlet and the distribution conduit.