"The proof tests validate the structural design of the aircraft, and give us confidence that we can operate this plane safely and reliably in all anticipated carrier environments," said Janis Pamiljans, vice president of the Navy UCAS program for Northrop Grumman's Aerospace Systems sector. "In particular, we now know that AV-2 can handle the stresses, strains and dynamic loads associated with catapult launches and arrested landings on the carrier deck, and air-to-air refueling." 

AV-2 is identical to the first X-47B UCAS demonstration aircraft (AV-1) – which successfully completed its historic 29-minute first flight at Edwards Air Force Base, Calif. on Feb. 4  – except that it will be equipped with aerial refueling equipment. Northrop Grumman plans to use AV-2 to demonstrate unmanned air-to-air refueling – using both the U.S. Air Force's boom/receptacle approach and the Navy's probe and drogue approach – in 2014 as part of a technology demonstration related to the current UCAS-D contract. 

The proof testing performed on AV-2 simulated eight design conditions, such as a 3-G symmetrical pull up and a 2.4G rolling pullout; and five conditions expected to occur on the ground, including takeoff and landing, said Sarah Beaudin, Northrop Grumman's AV-2 manager.  

One of the ground tests included pulling on the nose gear (to simulate a catapult launch) and the tail hook (to simulate an arrested landing on the carrier deck) at the same time to provide a special combined load case for test with the required margins. One of the flight conditions simulated the forces produced by turbulence that could occur during air-to-air refueling, a more demanding requirement than that used to proof test AV-1 in 2009.