This pilot claimed a kill over a PO-2 while flying an AD-4N with his Radar Operator CWO Vernon Kramer. However I cannot find a picture of an AD-4N that would allow a second crewman in the cockpit area. The later AD-5 was configured for three crew but all the photos I have seen of the AD-4N shows what looks like the single-seat version. Was the radar operator in the AD-4N concealed within the fuselage.
http://www.mcara.us/AD-4N.html
I notice what looks like a door in the fuselage is that a crew hatch?