Surrogate flight tests of the software and systems for the Northrop Grumman X-47B unmanned combat aircraft system demonstrator (UCAS-D) have resulted in “hands-free” landings of an F/A-18 Hornet on a U.S. Navy carrier.

Controlled by the avionics and software from the X-47B, the F/A-18 conducted 58 coupled approaches to the USS Eisenhower on July 2, including 16 intentional touch-and-gos and six arrested landings, program officials say.

The tests keep the UCAS-D program on track for carrier trials of the unmanned X-47B in 2013. The first aircraft has flown at Edwards AFB, Calif., and both air vehicles will be delivered to the NAS Patuxent River, Md., test center for shore-based testing in 2012.

Acting as a surrogate, the F/A-18 showed the X-47B will be able to land autonomously under command from the ship. The tests included 28 straight-in, or Case 1, instrument approaches where the unmanned system took over control 8 mi. behind the ship.

The other 30 were visual, or Case 3, approaches where the system took over control as the F/A-18 passed the carrier on the downwind leg and then turned the aircraft on to its final approach, says Capt. Jaime Engdahl, Navy UCAS program manager.

Flights were conducted using precision GPS and Tactical Targeting Network Technology high-speed data links to navigate relative to the carrier and send commands to the aircraft.

Engdahl says the tests demonstrated the Navy’s distributed control concept, in which a mission operator on the carrier always has positive control of the aircraft, but the ship’s air traffic controller, the air boss in the tower and landing signals officer on the flight deck can send commands to the unmanned vehicle as they would to a manned aircraft.

“You send basic commands to the aircraft and the system calculates all the paths itself and puts together a profile,” says Don Blottenberger, deputy program manager. “The carrier exercises oversight and override, everything else is automated.”

The next steps are to complete flight-envelope expansion at Edwards and then ship the X-47Bs to Patuxent River for shore-based catapult launches, arrested landings and carrier pattern work through 2012, Engdahl says.

Further surrogate test flights are planned next year, working with the USS Truman, and one of the X-47Bs will be hoisted aboard the carrier to evaluate maneuvering of the unmanned aircraft on the flight deck.

Carrier trials of the X-47B in 2013 will be followed in 2014 by flight tests of autonomous aerial refueling. Flight tests for this phase of the program will begin late this year using a Learjet as a surrogate.