If an airport has an Airport Diagram, you can bring it up so that it overlays the map (and thus overlays the Realview). Tap the airport to bring up the Quickview menu, then View Plates, then the Airport Diagram.
I don't think there's an option to make the Airport Diagram automatically pop up on the map. (The Realview is really treated as part of the map, though it only comes into view when zoomed close in.)