The U.S. Air Force's F-16D, tail # 840, is currently assigned and tested at the 416th Flight Test Squadron and was initally used as the Automatic Collision Avoidance Technology, or ACAT, aircraft in the ACAT Fighter Risk Reduction Project. This project was created to develop collision avoidance technologies for fighter/attack aircraft that would reduce the risk of ground and mid-air collisions. (Courtesy photo)