The X-47B unmanned jet successfully landed twice last week on the aircraft carrier George H.W. Bush, but a third attempt was unsuccessful. Another landing attempt on Monday was aborted before the aircraft reached the carrier. (Christopher P. Cavas / Staff)
WASHINGTON — The X-47B unmanned jet, which successfully landed twice last week on an aircraft carrier, was unable to repeat the feat Monday, U.S. Navy sources confirmed July 16.
The aircraft nailed its first two landing attempts July 10 on the USS George H. W. Bush, but a third landing that day was aborted when the aircraft’s systems detected a problem with an onboard computer. Following its programming, the aircraft then flew to a “divert” field at Wallops Island, Va., where it remains.
Naval Air Systems Command (NAVAIR) and Northrop Grumman engineers were back on board the carrier Monday to try for a third successful “trap,” this time using the other of two X-47B aircraft.
But it didn’t happen. The aircraft developed technical issues while in flight from Naval Air Station Patuxent River, Md., to the ship and officials decided to abort the attempt before the X-47B reached the vicinity of the carrier, steaming off the U.S. east coast.
Nevertheless, officials have termed the tests “successful” in that the program’s objectives of demonstrating unmanned flight on and off an aircraft carrier were achieved. And at least in the case of the July 10 waveoff, the system’s ability to detect and respond to a problem was validated, if unintentionally. But the fact is that four times the Navy attempted to land the aircraft on the ship, and only two attempts were successful.
Officials point out that the program’s requirements called only for one successful landing, although testers targeted three at-sea traps.
"Initial parameters for the test required three traps on board the carrier,” a Navy official said Tuesday. “However, after two successful traps and two wave-offs, the Navy is confident it has collected the data necessary to advance this program and develop the requirements for UCLASS."
The Unmanned Carrier Launched Surveillance and Strike Program is the follow-on effort to develop an operational unmanned aircraft using technologies and lessons learned from the X-47. Navy officials hope to field a UCLASS aircraft by 2019.
Underscoring the effort’s importance, the July 10 event was attended by Secretary of the Navy Ray Mabus, Adm. Jonathan Greenert, chief of naval operations, and more than two dozen media representatives. The secretary and CNO were effusive in their praise for the program and the technological achievement, and of the historic nature of the events. The successful landing received extensive national and international media coverage, as did the first catapult launch from the ship on May 14.
With the failure of the July 15 test, the program’s flying days are all but over. The aircraft used on Monday, numbered 501, remains at Pax River, and no further X-47B flying tests are scheduled after 502 flies from Wallops Island to Pax River.
Funding for the X-47B, under the Unmanned Combat Air System Aircraft Carrier Demonstration (UCAS-D) program, runs out at the end of September with the close of the fiscal year.
A statement was issued by NAVAIR late Tuesday afternoon about Monday’s incident, reproduced here in full:
“The Unmanned Combat Air System Demonstration (UCAS-D) program successfully completed testing with the X-47B aboard USS George H.W. Bush (CVN 77) July 15, culminating a decade of Navy unmanned integration efforts that show the Navy's readiness to move forward with unmanned carrier aviation, says Rear Adm. Mat Winter, who oversees the Program Executive Office for Unmanned Aviation and Strike Weapons in Patuxent River, Md.
“On July 10, the X-47B completed the first-ever arrested landing of an unmanned aircraft aboard CVN 77. Shortly after the initial landing, the aircraft was launched off the ship using the carrier's catapult and completed a second successful landing.
“ ‘We accomplished the vast majority of our carrier demonstration objectives during our 11 days at sea aboard CVN 77 in May," said Capt Jaime Engdahl, Navy UCAS program manager. "The final end-to-end test of the UCAS including multiple arrested landings, flight deck operations, steam catapults, to include hot refueling procedures, was accomplished on July 10 and the procedures, the X-47B aircraft and the entire carrier system passed with flying colors.’”
“During its final approach to the carrier on July 10, the X-47B aircraft, "Salty Dog 502", self-detected a navigation computer anomaly that required the air vehicle to return to shore, where it landed at Wallops Island Air Field. The X-47B navigated to the facility and landed without incident. Salty Dog 502 is scheduled to fly back to Pax River later this week.
“Aircraft "Salty Dog 501" was launched to the ship on July 15 to collect additional shipboard landing data. During the flight, the aircraft experienced a minor test instrumentation issue and returned to NAS Patuxent River, where it safely landed. There were no additional opportunities for testing aboard CVN 77, which returned to port today.
“ ‘Completing the first-ever arrested landing with an autonomous, unmanned aircraft is truly a revolutionary accomplishment for the U.S. Navy," said Winter. "This demonstration has successfully matured the needed critical technologies for operations in the actual carrier environment and has set the stage for Naval Aviation to blaze the trail for relevant unmanned, carrier-based warfighting capabilities.’”