The unmanned air vehicle (UAV) X-47B has certainly achieved its share of historic milestones. The program’s swift evolvement from dream to reality continues to captivate with each success. "We first flew this aircraft at Patuxent River less than a year ago, so this is a very rapid demonstration program," said Capt. Jaime Engdahl, program manager for the Unmanned Combat Air Systems (UCAS) program office, speaking to reporters in mid-July.
On July 10, the X-47B UCAS demonstrator completed an arrested landing in the most complex of environments: an aircraft carrier. As with previous X-47B tests, including catapult-launches and touch and go landings, the USS George H.W. Bush (CVN 77) had the distinction of providing the test environment necessary for the UAV to prove its mettle. "The ability to bring together the technical and operational capabilities of the X-47B into the carrier environment was nothing short of amazing," said Rear Adm. Mathias W. Winter, program executive officer for Unmanned Aviation and Strike Weapons at Patuxent River, Md.
A Product of Teamwork
The success of the X-47B program can be attributed to the colossal culmination of joint efforts by a team which truly reflects the modern Navy: military, civilians and contractors working side-by-side. "It was a great day, a lot of success, based on having a really integrated Navy industry team," said Northrup Grumman Vice President Carl Johnson. From requirements specialists to engineers to pilots, each team member in some way enabled the X-47B’s success.
Engdahl was full of praise for the people who made the achievements of the UAV a reality, recognizing the team for their exceptional work in the midst of such an intricately wrought environment. "As I was standing on the flight deck, you know what struck me was the ease with which everything happened and the entire team executed; but there were over 400 people on this team, distributed across the country — on the ship, ashore … the logistics, the entire crew of the USS George H.W. Bush, and I thought about the true marvel, the complexity of carrier aviation; and then to put X-47B in the middle of it, it was great."
Engdahl also said that the team correctly projected exactly where the aircraft would land and which wire it would engage. "What we saw out there was that they were right on," he said.
A Day of Firsts
The demonstration was the first time a tailless, unmanned autonomous aircraft landed on a modern aircraft carrier. This test marks an historic event for naval aviation that Navy leaders believe will impact the way the Navy integrates manned and unmanned aircraft on the carrier flight deck in the future. It was a day that will not soon be forgotten by those who witnessed the triumphant landing of the X-47B, among them Secretary of the Navy Ray Mabus and Chief of Naval Operations Adm. Jonathan Greenert.
X-47B, or "Salty Dog 502," launched on schedule from Patuxent River, Md. Supported by two F-18 aircraft, the UAV successfully executed a carrier landing approach right above the flight deck of the George H.W. Bush, situated off the coast of Virginia. The landing signal officer initiated wave-off by sending a command to X-47B using the "pickle" switch — a device that controls a combination of lights attached to the optical landing system. For this first approach — as planned — the UAV responded by autonomously climbing and turning downwind for a second approach attempt.
X-47B then flew the second approach, reaching the first arrested landing on deck at 1339 and 50 seconds – 10 seconds earlier than originally planned in test schedule timelines published weeks prior to the event. "I think that’s a very significant event considering the complexity of this entire thing," Engdahl said.
At the time of landing, X-47B’s weight was approximately 38,000 pounds. Winds were nominal at 28 knots as the UAV approached the carrier. The aircraft engaged the number three wire on the flight deck while traveling at 124 knots relative to the carrier deck before landing on the center line and rolling to a stop.
In addition to accomplishing its historic first landing, X-47B landed with other aircraft operating on the carrier deck — a crucial event for the burgeoning era of the unmanned aerial vehicle.
After landing, X-47B’s arresting hook was retracted, and the aircraft taxied forward. Flight data was reviewed over the course of 30 minutes before the UAV was taxied to catapult; at this point, the aircraft’s weight had decreased to approximately 37,000 pounds. Upon reaching the catapult, X-47B was launched back into the pattern.
For the second carrier landing, X-47B engaged the number two wire while traveling at a speed of 118 knots. It was then moved to another part of the deck for hot refueling, another first aboard the George H.W. Bush.
According to Engdahl, it was also the first time they had demonstrated end-to-end carrier flight operations.
After the second catapult launch, the UAV experienced a minor subsystem malfunction with one of its three precision navigation computers. However, because X-47B is equipped with pre-planned logic, it was able to self-detect anomalies and communicated with the mission control operator about its findings. When it was determined that weather would be below minimums (specific to types of airspace and altitudes) at the primary shore-based landing site, Patuxent River, X-47B transited to the assigned shore-based weather divert landing site, Wallops Island Air Field where it landed without incident.
Engdahl said, "[L]anding aboard an aircraft carrier is extremely demanding; the accuracy, the integrity, the reliability that you need is critical to the safety of the aircraft, and the fact that we’re landing on a ship in close proximity to flight deck personnel and other aircraft … you have to design [the aircraft] with unprecedented levels of reliability and system safety, and then when you need to make that call, you just do."
Rear Adm. Winter said that X-47B did everything it was designed to do. "It executed appropriately and we learned a lot in the off-nominal behavior scenario that we would have otherwise just continued to understand through modeling and simulation."
The Future of X-47B
On July 15, another X-47B vehicle known as "Salty Dog 501" tried to land on the Bush to allow the Navy to collect additional shipboard landing data. But this time, "the aircraft experienced a minor test instrumentation issue and returned to NAS Patuxent River, where it safely landed," according to the Navy.
During the testing and evaluation phase of the UCAS-D program, the air vehicle, control system and connectivity, and carrier integration technologies have continued to mature.
The UCAS-D program has likewise developed the concept of operations and demonstrated the technology for follow-on unmanned carrier-based aircraft. The program seamlessly integrated unmanned systems into the carrier environment with minimal changes to existing equipment and concept of operations.
Though the X-47B program was originally planned to be retired at the end of this year, Naval Air Systems Command (NAVAIR) announced plans to keep flying X-47B into 2014 as part of the UCAS-D program in early August.
According to a Navy official, NAVAIR has decided put Salty Dog 501 and Salty Dog 502 through additional tests, though the type of testing is not being disclosed at this time. This news arrives on the heels of Rear Adm. Winter's August 4 statement to Washington D.C. television station WJLA. "I believe you will see continued operation of the X-47B — at least into the fiscal year 2014 time period," Winter said. "As we go forward, we are continuing to assess its operational opportunities."
For the moment, Salty Dog 501 is stationed at Patuxent River while Salty Dog 502 remains at Wallops Island.
NAVAIR and the Program Executive Office for Unmanned Aviation and Strike Weapons (PEO (U&W)) are conducting preliminary design reviews of Boeing, Lockheed Martin, Northrop Grumman and General Atomics Air Segment designs, according to the Deputy Chief of Naval Operations for Information Dominance (N2/N6).
The UCLASS program will support the fleet with a carrier-based 24/7 intelligence, surveillance and reconnaissance and precision-strike capability. NAVAIR plans to issue a draft UCLASS request for proposal later this month.
Heather Rutherford is the CHIPS assistant editor. She can be reached at firstname.lastname@example.org.