The US Navy’s Northrop Grumman X-47B unmanned combat air system – demonstration (UCAS-D) testbed has carried out a dry aerial refuelling contact with a tanker ahead of fuel transfer testing.

The X-47B engaged with the Omega Boeing K-707 tanker over Chesapeake Bay on 15 April after taking off from NAS Patuxent River in Maryland, but no fuel was transferred, according to the US Naval Air Systems Command.

Wet air-to-air refuelling trials are expected to take place soon, but no further details on the trials have been disclosed.

X-47B dry ARR connection - NAVAIR

Naval Air Systems Command

The project began in 2007 under a $635 million programme and was subsequently declared complete in 2013, after it achieved a number of targets – including the UAV performing an arrested carrier landing on the USS George HW Bush in July that year.

Northrop Grumman then received an additional $63 million from the navy to carry out “post-demonstration” development of UCAS-D in June 2014.

The contract – dubbed Phase II – funded continued development of the test vehicle, and work was expected to be complete in March 2015.

The USN’s Northrop Grumman MQ-4C Triton UAV has also been residing at Patuxent River in recent weeks, from where it carried out a flight with its onboard active electronically scanned array maritime search radar for the first time.

The multifunction active sensor completed first flight onboard the Triton on 18 April, following an extended risk reduction phase on a Gulfstream GII testbed.