The U.S. Air Force's use of C-5M "Super Galaxy" heavy transport aircraft to refuel KC-10 "Extender" tankers is another milestone in the history of military aviation. Originally conceived in the 1920s, in-flight refueling has evolved from a dangerous stunt to an important part of the infrastructure of major military powers. The aim was to significantly extend the range of fighter aircraft to avoid a problem that often occurred during World War II, in which bombers flew without the escort of shorter-range fighters and the fighters had to turn back.
Aerial refueling technology also allows the Air Force to perform ultra-long-range missions, such as the famous air raid on Port Stanley Airport during the Falklands War in 1982. At that time, the British-based Vulcan bombers flew directly into the South Atlantic and then returned to the mainland without landing.
Today, the process by which a tanker uses a mechanical boom to connect to a trailing aircraft and pump fuel to it may look the same as the opening sequence of Dr. Strangelove, but it has evolved considerably over the past sixty years. Rather than relying on two dedicated pilots and one skilled boom operator, engineers are developing increasingly autonomous systems that control both the aircraft and the boom, improving safety and efficiency.
However, how to refuel the tanker remains a problem. The obvious answer is to return to base and reload, or to use a second tanker to refuel the first, but both methods would mean that the tankers would be out of action while they could be refueling other aircraft.
To solve this problem, the U.S. Air Force's 22nd Airlift Squadron (AS) is trying a new concept. On December 12, a C-5M Super Galaxy transport aircraft connected with a KC-10 stretch aircraft over Northern California and Oregon. From the outside, this is just an ordinary refueling operation, but in fact it is running in reverse. Instead of injecting aviation fuel into the C-5M, the C-5M pumps the fuel back into the KC-10 tanker. In this case, 23,500 pounds (10,700 kg) of fuel was completed in approximately 30 minutes.
According to the Air Force, the recent demonstration was an effort to collect data to further refine the technology, especially since the two aircraft will fly differently as their weight changes. If successful, this could mean air missions can stay airborne longer and more aircraft can fly missions over greater distances.
"Using the C-5 as a giant floating tank allows more tankers to be in place to unload fuel for fighter or maneuver aircraft, rather than having to use one tanker to refuel another, which would tie up tanker resources on the mission," said Maj. Justin Wilson, the Air Force's 22nd AS standards and evaluation director and C-5M evaluation pilot. "This allows for more tankers in the theater and extends their range or orbit time."