U.S. Air Force Staff Sgt. Adrian Navarro, 926th Aircraft Maintenance Squadron crew chief, reads over a technical order log during the Mission Employment Phase exercise, Dec. 7, 2012, at Nellis Air Force Base, Nev. The exercise is hosted north of Las Vegas on the Nevada Test and Training Range - the U.S. Air Force's premier military training area with more than 12,000 square miles of airspace and 2.9 million acres of land. (U.S. Air Force photo/Senior Airman Brett Clashman)