The successful catapult test of Northrop Grumman’s X-47B Unmanned Combat Air System Demonstrator (UCAS-D) could prove important for both unmanned and manned naval aviation, U.S. Navy officers said after the May 14 launch from the aircraft carrier USS George H.W. Bush, in a Navy test range area some 100 mi. off the Virginia coast.
The launch of X-47B AV-2, at a weight of 41,000 lb. and an end speed of 171 kt., was followed by two approaches to the ship leading to intentional wave-offs, the second at a height of 50 ft. above the deck. The aircraft then returned to Patuxent River Naval Air Station, Md. Later this week, an X-47B is due to return to the Bush and perform touch-and-go landings to verify the accuracy of the approach and landing guidance and flight control systems, and the vehicle’s ability to stay on centerline on deck.
It had been hoped the aircraft would conduct arrested landings during this at-sea period, but bad weather at Patuxent River prevented the completion of some tests — heavy-load arrestments and high-sink-rate landings — that were needed to earn formal Navy approval to make an arrested landing at sea. These tests should be finished in June and a carrier should be available in July-August.
This is expected to mark the end of the X-47Bs’ flying career. There are no plans for further flight tests in the UCAS-D program and, so far, no other program or agency has shown interest in using the Navy assets. Earlier plans called for an autonomous inflight refueling test to be carried out after the carrier landings, but these tests will instead be performed (for probe-and-drogue refueling only) using Calspan’s Learjet test aircraft, with flight control software that emulates the all-wing, “cranked kite” X-47B.
X-47B test results will clear the way for the U.S. Navy to launch a fast-track Unmanned Carrier Launched Airborne Surveillance and Strike (Uclass) program at a manageable level of technical risk. Navy officials plan to release a request for proposals for Uclass in the first quarter of next year and select a single air vehicle system contractor by the end of fiscal 2014, with the aim of achieving an initial operational capability (IOC) within six years.
IOC is defined as the ability to sustain two separate intelligence, surveillance and reconnaissance (ISR) orbits, on a 24/7 basis, at a “tactically significant range.” Uclass is primarily an ISR asset but will have the ability to perform limited strikes against “highly defended and dangerous” targets, according to Rear Adm. Mat Winter, Navy program executive officer for unmanned aviation and strike systems.
The X-47B team will remain together through fiscal 2014 to analyze data and transfer lessons to other programs. Capt. Jaime Engdahl said after the launch that “we see direct opportunities for improving safety and effectiveness of operation for both manned and unmanned aircraft,” while Winter commented that the Naval Air Warfare Center is looking at applications of the X-47B’s landing guidance technology to manned aircraft.
The hardware used in the X-47B program is unique, but similar in principle to the Joint Precision Approach and Landing System being developed for all aircraft carriers to replace today’s radar-based auto-land system. The latter is limited because of telltale radar emissions, an inability to handle more than one aircraft at a time, and because it will not work properly with the stealthy F-35.