U.S. Air Force pararescueman Todd Popovich, assigned to the 48th Rescue Squadron Davis Monthan AFB., scans over the desert floor for survivors during a search and rescue mission aboard a HH-60 Pave Hawk helicopter at Angel Thunder 2011, Oct. 11, 2011. Approximately 1,400 U.S. military, federal and state employees and coalition forces are participating in the 6th Annual Angel Thunder Exercise. Angel Thunder is the world's largest military search and rescue exercise in the world.