A B-52 bomber crashed shortly after takeoff Monday morning at a U.S. Air Force base in Southern California’s Mojave Desert, and all eight people aboard have dead, military officials said. “We lost eight great Americans," James Hayes, the Deputy Commander at Edwards Air Force Base, said at a news conference. Aerial footage showed virtually nothing left of the aircraft that went down around 11:20 a.m. during a routine test mission at the base, which is north of Los Angeles, the base said on its Facebook page. Black smoke rose from a large swath of charred desert near what appeared to be a runway on the base, with emergency vehicles nearby. It was not immediately clear what caused the crash.