A Lockheed Martin test pilot was killed after his US military F-22 aircraft, the world's most advanced fighter jet, crashed in the southern California desert, the aerospace giant said. David Cooley, 49, was on a test mission in an Air Force F-22 when it crashed at about 10:00 am (1700 GMT), approximately 35 miles (56 kilometers) northeast of California's Edwards Air Force Base, Lockheed Martin said in a statement. Cooley was a 21-year Air Force veteran who joined Lockheed Martin in 2003, the aerospace firm said. Earlier the Air Force said the crash was only the second involving an F-22.