A senior U.S. Air Force officer was killed Monday when the F-16 fighter plane he was flying crashed in a field northeast of Madrid, Spanish and U.S. authorities said. A Pentagon spokesman confirmed Tuesday that Air Force Maj. Gen. Winfield Scott Harpe, 51, commander of the 16th Air Force base in Torrejon, Spain, was killed when his fighter crashed about 6:45 p.m. Monday on a training flight. Other air bases in the 16th Air Force are in Greece, Italy and Turkey. Air Force officials said Harpe was the only person aboard and the jet carried no weapons. Weather conditions were clear when the F-16 went down, and the cause of the crash was not immediately known.