WASHINGTON — The remote vision system for the U.S. Air Force’s latest tanker was meant to transform how the service conducts aerial refueling. It did bring about change — but the service and the aircraft’s manufacturer, Boeing, concede it hasn’t lived up to all its expectations.
Now, after years of halting development and at times contentious negotiations, the Air Force and KC-46A Pegasus manufacturer Boeing say the company and its primary subcontractor, Collins Aerospace, have developed the right solution. Even so, implementation remains more than two years away.
The new version of the vision system, dubbed RVS 2.0, uses 4K ultrahigh-definition cameras to give boom operators a full-color, sharp 3D image as they guide the refueling boom into the receiver aircraft.
The Air Force, which last year approved the design for the new RVS, says the upgrade will eliminate the KC-46′s longstanding issue with lighting conditions — and that it’s time to start making this design a reality.
“We have the demos, we have the videos, we’ve flown it on [Boeing] planes … and it looks magnificent,” Lt. Col. Joshua Renfro, the head of the Air Force’s KC-46 Cross-Functional Team, said in a January interview with Defense News.
RVS 2.0 was originally to be released in March 2024. But in October 2022, the Air Force announced a delay of 19 months, largely due to supply chain issues among Boeing subcontractors. Under the current timeline, RVS 2.0 will now arrive in October 2025, at which point testing and Federal Aviation Administration certifications will have ended, then system installation will begin on the Pegasus fleet.
The road to get to RVS 2.0 has been tough — and for Boeing, extraordinarily costly. The contractor has racked up roughly $6.8 billion in charges on the KC-46 program, as multiple problems with the tanker cropped up. Not all of those charges were related to the vision system, but Boeing regularly cited issues with the RVS in its quarterly earnings reports as it explained the KC-46′s latest charges. Boeing declined to say exactly how much this system has cost as part of those charges.
Problems out of the box
When the Air Force received its first KC-46 in January 2019, the event represented a dramatic change in how boom operators refuel aircraft. In older tankers, such as the KC-10 Extender and KC-135 Stratotanker, boom operators looked through a window in the back to steer the boom into the aircraft in need of fuel. In the KC-135, boom operators even lie on their stomachs while refueling.
In the KC-46, however, boom operators remain in their stations near the front of the tanker and use a system of cameras, sensors and screens to remotely refuel everything from fighter jets to bombers to cargo planes.
The concept was ambitious, and it struggled from the start. Not only was the first KC-46 a year late — Boeing originally set a goal to deliver it to the Air Force by the end of 2017 — but Air Force testers also identified problems with the Collins-made vision system before delivery. The issues were serious enough to be deemed a category 1 deficiency — the most serious of its type.
As Air Force testers put the KC-46 through its paces, Renfro explained, it became clear the original Remote Vision System had issues. It wasn’t responding quickly enough to sun and shadows, he said, and sometimes the image was distorted.
The Air Force sat down with Boeing for some “hard negotiations,” as Renfro called them, on how to get the Pegasus the vision system it needed. By April 2020, both parties reached an agreement to replace the original RVS with a redesigned vision system.
It took another two years before the service accepted the completed design for RVS 2.0. Its preliminary design review was held in May 2021, and Air Mobility Command originally expected the review to close that fall.
However, the new RVS also encountered problems. In January 2022, the command told reporters the design had “deficiencies with the panoramic visual system that detects, recognizes and identifies receiver aircraft.” The Air Force ultimately decided to keep the preliminary design review open while trying to identify how to address those technical risks.
Several months later, the service announced it closed the preliminary design review and accepted the completed design for RVS 2.0, and that Boeing would cover the costs under the terms of the engineering and manufacturing development contract.
Renfro said the Air Force had its experts in the room throughout the design process, working with Boeing’s engineers and boom operators on the new vision system. “A lot of small inputs, made over time by subject matter experts, lead to a product that is much better when it is delivered,” he added.
In a January visit to Boeing’s Arlington, Virginia, office, the company showed Defense News footage of how the new vision system works, and how it is an improvement over the old one.
Boeing had mounted both RVS versions side by side on their own KC-46s, and then in summer 2022 the firm conducted tests in the “stressing” lighting conditions that vexed the Pegasus, recording what each camera set saw. These test flights took place over the Pacific Northwest as well as California near Edwards Air Force Base.
Ernest Burns, Boeing’s test and evaluation chief boom operator, said stressing conditions include low sun over water while the Pegasus and the receiver aircraft are turning, or high sun angles casting shadows on the receiver aircraft. Another tricky condition could be a white, solid cloud deck below the planes, where a very white airplane that is receiving fuel could blend into the clouds.
In the 2D videos shown to Defense News, which the company said were unaltered, the difference was apparent.
The monochrome imagery captured by the original vision system’s cameras was oversaturated in some bright, high sun conditions. and in one video, parts of the white-topped RC-135 receiving the fuel started to wash out and disappear against the cloudy backdrop. As the plane turned, which sometimes must happen in combat to avoid threats, the guiding lines that are meant to help the operator steer the boom into the RC-135′s receptacle began fading on the screen.
In another operation over water, the black-and-white video showed shadows from the Pegasus masking the contact area of a C-17. When those details on the receiver aircraft start to disappear, the risk of accidental damage from a misguided boom becomes more likely.
But footage of the same operations captured by RVS 2.0 cameras showed the planes in full color, with higher resolution. The white edges of the RC-135 remained sharp and visible against the clouds, and the red guiding lines remained clear.
Boeing also showed off a station with the 3D display that boom operators would see through passive polarized glasses. The station showed video of nighttime refueling of an F-16 jet in 3D. The resulting imagery was crisp enough to make out the pilots’ heads turning in the cockpit, and include details such as buckles on their parachutes.
Each RVS 2.0 system has six cameras: one pair of color cameras to capture the 3D imagery; a second redundant pair as backup; and a pair of improved infrared cameras. It also has redesigned image processors, upgraded panoramic sensors and redesigned stations for boom operators.
Air Mobility Command wants RVS 2.0 as soon as possible, Renfro said, but for now it can make do with the current system. After all, he explained, the service made progress with the KC-46 last year during exercises in the Indo-Pacific region and the Middle East.
During the latter in August 2022, KC-46s refueled two F-15E Strike Eagle fighters carrying out regular operations for U.S. Central Command; the Air Force said that was the tanker’s first refueling mission as part of a real-world operation.
After that mission, Air Mobility Command head Gen. Mike Minihan signed off on the final interim capability release, opening up the KC-46 to worldwide deployments. The Pegasus is now cleared to carry out all refueling missions around the world on all aircraft, except the A-10 Warthog.
All that was done with the KC-46′s current technology, including the original vision system, Renfro said.
“We absolutely want [the updated vision system] as soon as we can get it, however we’ve learned to operate without and carry that additional risk for that time period,” he said.
Much remains undetermined about the process for retrofitting the RVS 2.0 on the fleet, he added. For example, it’s unclear how long it will take to install the updated system on all KC-46s once deliveries start in 2025, though it will surely take years, he explained.
Renfro also wondered what the retrofit process will look like, where it will take place and how long an individual plane’s upgrade will take. The process will be a heavy maintenance action, he said, though it remains unsettled whether the Air Force will combine the activity with regularly scheduled depot maintenance.
The service will also need to carefully plot the schedule for these upgrades to ensure it has enough KC-46s flying at any given time for missions, Renfro said.
“There will be some balance between: I need future capability, and I need to keep employing the capability that I’ve prove[d] and have come to rely on right now using the [KC-46] we have,” Renfro said.
In a statement to Defense News, the KC-46 program office said Boeing and Collins Aerospace are continuing detailed development work on the design presented at the June 2022 critical design review. That work will lead to the establishment of a system integration laboratory, the program office said, where more systems development, early system-level testing and eventually certification testing will take place.
The Air Force is “well underway” on setting up the integration laboratory, the program office noted, and it expects RVS 2.0′s fidelity will continue to improve as its hardware and software mature.
The integration laboratory’s work — including qualification testing of subcomponents to ensure they meet the FAA’s and the military’s certification requirements — will end in flight testing of the new system, which will collect data used to certify airworthiness and aerial refueling clearances.
“Air refueling is an inherently risky business,” Renfro said. “We have two planes in close proximity, flying [hundreds of] miles an hour, that are intentionally touching one another. So there needs to be rigor in that process.”