X-47B Could Revolutionize Naval Aviation

Landing a plane on a bobbing aircraft carrier deck is one of the hardest maneuvers for any pilot. And after that's done, refuel the drone from a tanker in flight.  For years, the U.S. Navy and Northrop Grumman have worked on precise navigation technology that will make this possible. This year, the program stepped much closer to making this a reality.

The tailless, bat-winged craft, dubbed the X-47B, flew for the first time in February. And recently, an F/A-18 Hornet fighter jet equipped with an early version of the autonomous guidance software designed for the drone successfully landed on a carrier without a pilot on the stick and throttle. This precision navigation equipment is a "key technology" that allows the Unmanned Combat Air System Demonstration (UCAS-D) aircraft to navigate on approach with an accuracy of less than 10, said Capt. Jaime Engdahl, UCAS-D program manager at Naval Air Systems Command (NAVAIR).

While the primary goal of the UCAS-D program is to launch and land the aircraft on the carrier, officials must accomplish much more. Upon touchdown, crews must clear the drone from the runway within 45 seconds -- no easy feat - so other aircraft can land. Unlike many of the drones in use today, X-47B is fully autonomous, and special computer software keeps the composite aircraft aloft, according to Keith Carter, NAVAIR's chief engineer on the program.

"There is no pilot flying at all," Carter said. "The aircraft responds to external stimuli." While the basic airframe shape, which shares many flight technologies and design similarities with the B-2 bomber, is not groundbreaking, the precision GPS computer system is new technology. The first of two demonstrator aircraft has been flying test missions at Edwards Air Force Base in California since its first flight in February. Due to the autonomous nature of the aircraft, many hours are spent conducting mission planning for the flight tests, according to Engdahl.

A second aircraft is undergoing tests in preparation for its first flight.  Prior to making its first carrier landing, one X-47B will conduct air traffic control exercises, which includes transferring control from a ground station at Patuxent River to a station on the carrier. Aside from takeoffs and landings, the X-47B will spend time on the carrier conducting other tests. Before the first flight, program officials plan to put a drone on the flight deck and drive it around using a wireless controller. The crew also will conduct maintenance demonstrations in advance of carrier touch-and-goes and landings, which are expected in 2013.

New and precise GPS equipment on the carrier, coupled with an inertial navigation system, will provide the precise position of the carrier deck. "That gives you [the] … pitch, roll, yaw of the ship," Engdahl said.
Computers pick the landing point, which is then transmitted to the X-47B. "This is forward-leading technology," Engdahl said. "It's relevant to the future of unmanned carrier aircraft." Three separate computers on the drone evaluate the landing. If they believe a safe landing is not possible, the aircraft climbs and goes around for another approach.

As another safety precaution, a landing signal officer on the ship will hold a controller that will clear the aircraft to land. If a signal is not given to the aircraft, it will circle around and make another attempt. And there's more to landing on a carrier than just landing. "There's an entire dance that takes about 45 seconds to get it trapped, rolled out, pulled back, wings folded, taxi out of the landing area, so that you can land the next airplane," Engdahl said.

After the carrier landings, the second test aircraft will conduct air-to-air refueling using both U.S. Air Force and Navy refueling systems.  "It truly does portend a significant change in the advantages and the power and the versatility of naval carrier aviation," Adm. Gary Roughead, chief of naval operations, said of the X-47B. "If we can blend the unmanned on an aircraft carrier and the manned [aircraft] on an aircraft carrier, we've changed the dimension of carrier naval aviation in a way that has not happened in decades."