Call it the KC-17.
On Dec. 2, a C-17 Globemaster III refueled a B-2 Spirit stealth bomber on the ground for the first time — the latest test of the cargo jet’s versatility. The experiment was a milestone for the bomber as well, expanding its ability to hopscotch around the globe.
“What happens when you need fuel but there’s no air refueling available? Call us,” Joint Base Charleston, South Carolina, said on Twitter.
The experiment is part of a string of events over the past few years that have aimed to give the Air Force’s mobility fleet more flexibility in combat, rather than stringently sticking to the missions for which its jets were built. It’s taken on new urgency in an era of nonstop aerial refueling sorties that have stretched the Air Force thin and forced it to consider outsourcing those missions.
“This capability was designed into the C-17 but not considered widely necessary in previous use of the aircraft,” said Maj. Ross Jensen, 437th Operations Group special operations division deputy director, in an email. “As we prepare for the future, the Air Force is looking for additional ways to increase the operational range of aircraft without solely using air refueling platforms.”
In the most recent exercise, airmen from the 15th Airlift Squadron at JB Charleston and the 509th Bomb Wing at Whiteman AFB, Missouri, gathered at Edwards Air Force Base, California, to practice “cold-to-cold aircraft fueling,” meaning the C-17 transferred gas to the B-2 with their engines turned off.
That was made possible by installing a boost pump, a refueling system that pushes gas from one plane’s main tank to another one’s engine.
Airmen have refueled and defueled airframes using the Globemaster III with its engines off for decades.
“The C-17 was designed with a method to provide excess fuel to other vehicles, fuel storage containers, and even other aircraft while on the ground,” Jensen said. “This capability has been practiced off and on with all of these methods since the C-17 became operational in the 1990s.”
Over the past few years, however, C-17 crews have learned to gas up other aircraft with the engines running, so jets can get in and out faster.
“Specialized fueling operations,” like that with the B-2, typically involve taking gas out of a C-17 or C-130 with a fuel truck, which in turn refuels another aircraft. Mobility aircraft can also directly hook up to another airframe for refueling.
“All C-17 crew members are now training to perform special fueling procedures. These procedures enhance our capability to … enable the joint fight,” Jensen said.
Using the C-17 as a tanker is gaining traction in larger training exercises.
In October, the 62nd Airlift Wing at Joint Base Lewis-McChord, Washington, put its own resources to the test to refuel an F-15E Strike Eagle with a C-17 during Exercise Rainier War.
“Wet-wing” operations offload gas from the C-17′s tank into an R-11 refueling truck, then relay that into another airframe.
“This is the first time that we’ve brought in our own R-11 refueler, munitions, bomb loaders and the ‘multi-capable airmen’ package to do a re-arm and refuel of a fighter aircraft,” said exercise director Lt. Col. Matthew Weinberg. “We didn’t have access to anything … other than what we brought.”
That let them move the mission along faster than if they had tried to plan out a safe area for a pit stop in the fictitious enemy territory.
In June 2021, JB Lewis-McChord’s 4th Airlift Squadron used a C-17 to refuel two F-16 Fighting Falcon jets in Greenland — the first time the North American Aerospace Defense Command (NORAD) had rehearsed that mission with the Globemaster III in the Arctic.
“The C-17 would supplement the C-130 refueling capability” for air defense missions in North America, the Air Force said.
And in August, the Marine Corps tried transferring fuel from a C-17 to a still-running MV-22 Osprey. The “hot pit” experiment proved the tiltrotor aircraft can gas up in 10 minutes or less, freeing it to fly more missions.
In practice, temporarily turning the Air Force’s C-17s into tankers can create more than 200 refueling points across the world. That could be particularly useful in the vast Indo-Pacific, where aircraft need more top-offs to get around, or in places where brick-and-mortar bases become enemy targets. It also takes pressure off of the aging KC-10 Extender and KC-135 Stratotanker planes as well as the delayed KC-46 Pegasus fleet.
“Using excess fuel from a C-17, as well as all other [mobility] platforms at a forward location, is one option planners can consider,” Jensen said.
Rachel Cohen joined Air Force Times as senior reporter in March 2021. Her work has appeared in Air Force Magazine, Inside Defense, Inside Health Policy, the Frederick News-Post (Md.), the Washington Post, and others.