The Navy’s unmanned combat air vehicle demonstrator, the X-47B, not only plugged into a refueling basket trailing behind an Omega KC-707 tanker, but it also sipped gas from it for the first time. This historic mission is slated to be the X-47Bs last in what has been an incredibly successful test program with huge implications.

During the mission, which is the capstone to a series of refueling tests this week, the X-47B took off, flew out to the tanker, formed up with it, engaged the basket, and then sucked 4,000 pounds of fuel from it before heading back home to Naval Air Station Patuxent River for an autonomous landing.


The aircraft’s refueling system and software was developed over many years, and could provide autonomous aerial refueling for future Navy UCAVs operating from aircraft carriers.

According to Northrop Grumman:

Northrop Grumman began developing AAR (air-to-air refueling) technology for both Navy and Air Force application nearly a decade ago, pioneering a “hybrid” approach that integrates both GPS and infrared imaging to enhance navigational precision and hedge against GPS disruption. Initial UCAS-D flight testing began in 2012 using a manned Learjet as a surrogate for the X-47B. These successful proof-of-concept flights demonstrated the overall feasibility of the X-47B AAR system and helped refine its navigation, command and control, and infrared sensor processing components.


Unless something drastically changes, the fact that the X-47B will be retired even though the stealthy “cranked kite” flying wings (there are two X-47B demonstrators, Salty Dog 501 & 502) have only used up 20 percent of their service life remains somewhat of a controversial issue.

Considering that the Unmanned Carrier Launched Surveillance and Strike (UCLASS) program, which is the Navy’s production follow-on contract to the X-47B program, keeps getting delayed over requirements squabbling in Washington, keeping these incredibly capable machines in testing seems like a no-brainer.


The success of the X-47B program also reminded USAF, and the public, just what Northrop Grumman and their stealthy flying wings are capable. How this will factor in to the USAF’s looming and shadowy Long Range Strike Bomber (LRS-B) contract award is uncertain, but the shape of the X-47B is highly rumored to very similar to the Northrop Grumman’s entrant into that contest.


Regardless of what will happen next in any of these programs-related procurement programs, these two super-drones will go down in history as some of the most game-changing test aircraft ever built. As a result, their final orders will surely include sitting sentry in America’s most prominent aviation museums.

U.S. Navy Photograph by Liz Wolter

Tyler Rogoway is a defense journalist and photographer who maintains the website Foxtrot Alpha for You can reach Tyler with story ideas or direct comments regarding this or any other defense topic via the email address