The Air Force F-16D Automatic Collision Avoidance Technology aircraft flew at low levels above the Sierra Nevada Mountains to test the ACAT Fighter Risk Reduction Project to develop collision avoidance technologies for aircraft, to reduce the risk of ground collisions.

An ER-2 high-altitude Earth science aircraft banks away during a flight over the southern Sierra Nevada. NASA’s Armstrong Flight Research Center operates two of the Lockheed-built aircraft on a wide variety of environmental science, atmospheric sampling, and satellite data verification missions.