An A160T prepares to land following a high-altitude hover-out-of-ground-effect (HOGE) flight demonstration May 9, 2008 at the U.S. Army's Yuma Proving Ground in Arizona. The A160T reached an altitude of 20,000 feet. Less than a week later, the same aircraft set an unofficial endurance record for unmanned aerial vehicles weighing between 1,102 and 5,511 pounds (500 to 2,500 kilograms) with an 18.7-hour flight.