Boeing completed another milestone in the delayed KC-46 tanker program yesterday. With great precision, a KC-46 linked up with a F-16 in the air and offloaded fuel. During a series of test maneuvers to test the flight interactions between the two aircraft, the F-16 maneuvered into the typical air refueling envelope are received 1,600 lbs of fuel. While the actually amount of fuel transferred was small, this represents a step forward in the long-delayed program to replace aging tanker fleet of the US Air Force.
In a press release, Colonel Christopher Coombs, U.S. Air Force KC-46 system program manager stated that “Today’s flight is an important milestone for the Air Force/Boeing team because it kicks off the Milestone C aerial refueling demonstration, which is the prerequisite for the low-rate initial production decision. We have a lot of work yet to do, but this is an exciting time for the airmen who are preparing to fly, maintain and support the KC-46 Pegasus for decades to come.”
The KC-46 represents a new generation of tankers. The KC-46 is unique in that the boom station will be located near the cockpit instead of the rear of the aircraft. Instead of windows, the boom operator will ‘see’ the refueling aircraft by wearing 3D goggles with large screens in front of the boom station. The images on the screens are presented from cameras mounted strategically on the rear of the aircraft.
According to Boeing, the KC-46 will soon begin refueling a number of other military aircraft as well, including a C-17, F/A-18, A-10 and AV-8B. Also known as EMD-2, the tanker made its first flight September 25, 2015 and has now completed 32 flights.
The program’s first test aircraft (EMD-1), a 767-2C, has completed more than 260 flight test hours to date since its first flight in December 2014. EMD-3 and EMD-4 will begin flight testing later this year.
PaineAirport.com published audio of the event. (Avgeekery first saw this posted at the website AboveTopSecret.com.) The audio of the test flight is fairly standard. The F-16 pilot begins a well-scripted profile by climbing to FL220 and calling out his location from 1 mile in regular increments to confirm the tanker’s instrumentation. As the flighter moves closer to the tanker, he climbs to FL230 and slides into a close trail position. The F-16 flies to various positions around the tanker to evaluate the “jet wash” turbulence behind the tanker. As the F-16 is maneuvering, the boom operator shared that the fighter drops out of view of the cameras. Eventually, the tanker drops down to a more traditional pre-contact position, well within the view of the cameras. The tanker plugs the F-16 and passes 1600 lbs of fuel while evaluating the boom envelope. Afterwards, preparations are made for a practice emergency separation. This practice separation is a maneuver done during air refueling to safely separate the formation in the event of an actual “breakaway” (unsafe maneuvering to include a rapid closure rate), loss of visual contact between the tanker and receiver, or a mechanical difficulty between one or both of the aircraft.
You can listen to the audio yourself here.