A hypersonic aircraft launched by the Air Force Tuesday spiraled out of control and was destroyed before it could reach its goal of speeding to 4,600 mph, Pentagon officials said Wednesday. The third test of the X-51A Waverider was launched Tuesday off the California coast from a B-52 modified bomber aircraft and was to fly for 300 seconds, reaching hypersonic speeds of Mach 6, but only flew for 16 seconds, according to the Air Force. Officials said a problem with a tail fin caused the missile-like vehicle to fly out of control before the main engine could be ignited, leading researchers to destroy it early. "A fault was identified with one of the cruiser control fins. Once the X-51 separated from the rocket booster, approximately 15 seconds later, the cruiser was not able to maintain control due to the faulty control fin and was lost," said a statement issued by the Air Force and quoted by CNN.