Air Force, Boeing Trying to Tackle Tanker Challenges
A KC-46 refuels a fighter jet.
The KC-46A Pegasus program — which will replace part of the Air Force’s fleet of aging aerial refueling tankers — has been dogged by problems for years. As the Air Force and Boeing work to fix remaining issues, officials and executives say the aircraft is finally on the right track.
Boeing has been working on the program — which was structured as a fixed-priced contract — for more than a decade and has eaten about $5 billion in cost overruns.
The program has faced several issues in recent years, most notably problems with its remote vision system. However, both Boeing and the Air Force say the program is turning a corner.
“While we work to rectify some discrepancies, we stand behind the KC-46 and believe it will be a great refueling capability for decades to come,” said Lt. Gen. David Nahom, the Air Force’s deputy chief of staff for plans and programs. “Even today, it has taken on many of the day-to-day refueling requirements and … our plan is to make full use of the KC-46 in the near term, while fixing discrepancies as soon as possible.”
The platform will be a key asset for the Air Force, he added during a Senate Armed Services airland subcommittee hearing in June. “We are getting use out of it right now, not just in limited air refueling, but also in airlift and air medical evacuation.”
In July, the service announced that Air Mobility Command Commander Gen. Jacqueline Van Ovost approved the centerline drogue system mission set as the Pegasus’ first interim capability release to meet joint force air refueling requirements.
The move will allow for more daily “taskable” operational capabilities and increase capacity for tanker fleet requirements, according to the Air Force.
“The last six months of operational use and programmatic evaluation indicate conditions have been met for ICR declaration of the centerline drogue system mission set,” Van Ovost said in a statement. “This decision reflects a risk-informed, data-driven, constraint-analyzed approach to releasing KC-46A operational capabilities to the joint force.”
In August, Van Ovost approved a second interim capability release mission set for the air refueling boom, according to the service.
However, while the KC-46’s critical technologies are fully mature, the program continues to experience design instability, according to a recent Government Accountability Office report, “Weapon Systems Annual Assessment,” that was released in June.
The government watchdog flagged six critical deficiencies that were discovered during development and operational testing that required design changes. That includes continued shortcomings with the remote vision system cameras and their displays. The issue “can cause the operator to scratch stealth aircraft with the boom during refueling due to poor visual acuity and inadequate depth perception,” the report said.
Two other deficiencies relate to fuel manifold leaks and auxiliary power unit drain mast cracks, which have resulted in increased maintenance and limited aircraft availability, GAO found.
Another issue is the auxiliary power unit duct clamps detaching, which could pose safety risks, according to GAO. There are also deficiencies related to the boom being too stiff during refueling attempts with lighter aircraft, which could result in its striking and damaging receiver aircraft.
Gen. Charles “CQ” Brown Jr., chief of staff of the Air Force, said work is underway to fix the issues, including the remote vision system. Both the service and Boeing are working to develop what they call the remote vision system 2.0.
“We are making great progress there with the Air Force engineers and with the Boeing engineers to bring that capability” into the fold, he said during a June hearing before the Senate Armed Services Committee. It is on track to deliver in the fiscal year 2023 timeframe, he added.
Paul Waugh, program executive officer for mobility and training aircraft, said the Air Force and Boeing are currently working through the design portion of RVS 2.0.
Mike Hafer, Boeing’s KC-46 global sales and marketing lead, said the Air Force wanted a wholesale redesign on the system.
“They were concerned that it didn’t have the visual acuity to acquire the receiver, and that visual acuity could also cause inadvertent contact with a receiver airplane that the boom operator … would not know about,” he told National Defense.
While developing RVS 2.0 was challenging and tough at first, it drove Boeing to sit down with the Air Force to develop and upgrade the system so that it is exactly what the service wants, he said.
“We’re literally redesigning this remote vision system with technology that did not exist when this contract was first signed,” he said. “Boeing is going, I would say, above and beyond to meet the warfighter’s requirements.”
The new system will include 4K ultra high-definition color cameras, monitors and displays; updates to the system’s video graphic computers; and fiber optics for fast relay and a high data rate, Hafer said.
“I see nothing but a good, positive trajectory for the program,” he said.
The Air Force has already accepted at least 47 KC-46s and will receive a total of 179 platforms, according to service officials and Boeing. The program is limited to 13 production lots, with the last planned procurement in 2027 and delivery in 2029.
The Air Force awarded Lots 6 and 7 for the program in January, increasing the number of production aircraft on contract to 94, according to the service. The Lot 8 contract for up to 15 aircraft is projected to be awarded in the second quarter of fiscal year 2022.
In President Joe Biden’s fiscal year 2022 budget request, which was released in May, the Air Force asked for $73.4 million in research, development, test and evaluation funding for ongoing KC-46 engineering and manufacturing development and post-production modification efforts.
“That would include the boom telescope actuator redesign effort resolving the stiff boom deficiency,” according to prepared testimony from Air Force officials for a SASC hearing. “Additionally, the budget requests $2.4 billion in procurement funding to award Lot 8.”
Lot 8 would include 14 aircraft plus associated spares, engines, support equipment and wing air refueling pods, according to the testimony.
Meanwhile, as the service works to resolve issues, it is looking to the future to what it calls its “bridge tanker” effort. The program is meant to bridge the gap at the end of KC-46 production and the service’s next-generation tanker, known as KC-Z, according to a sources-sought announcement released to industry by the Air Force Life Cycle Management Center in June.
The center is currently reviewing the responses it received from the request for information, Waugh said.
The Air Force is looking for 140 to 160 commercial derivative aircraft that must be operational by 2030, according to the RFI.
Lt. Gen. Duke Richardson, military deputy at the office of the assistant secretary of the Air Force for acquisition, technology and logistics, said the service is “not looking at something that is going to require a lot of time and effort to develop.”
The Air Force is still in the very early stages of the effort, he noted. “We will be at this for a few years, trying to figure out what our actual requirement is,” he added.
The service hopes to avoid the same issues that it encountered with the Pegasus, Waugh said.
“Our plan, at least right now, is to lay out a program that takes advantage of this non-developmental piece,” he said during a briefing with reporters in August. “We, hopefully, shouldn’t have a whole lot of the development issues that maybe we’ve seen on the KC-46.”
The Pegasus was the first new tanker the service developed since the KC-10 in the early 1980s, Waugh said. Now, the advancement of technologies such as digital engineering should alleviate some issues.
“We plan to incorporate as much of the digital tools into the bridge tanker as we can,” he said. “I certainly think if the KC-46 was a digital designed platform … it would allow us — on the manufacturing side especially — to make changes much more rapidly, understand some of the potential impacts of design changes on the weapon system, and then adjust those … [by modeling them] inside the digital models and see if we had the right solution going forward.”
Meanwhile, Richardson said it’s possible that the bridge tanker could be “uncrewed.”
A requirement for autonomy would have to come from operational users such as Air Mobility Command and Air Force headquarters, Waugh said. However, he noted that the aircraft is meant to be non-developmental, and the service does not currently have a fielded autonomous refueling system.
“You would have to do some work to that [to make it autonomous], so that makes it … developmental at some level,” he added.
Meanwhile, Waugh said he is aware that there is political “swirl” around the bridge tanker. The competition is expected to be hotly pursued by industry — particularly rivals Boeing and Airbus — just as the KC-46 was a decade ago. Legal wrangling and a protest resulted in Boeing ultimately receiving the KC-46 contract.
Hafer said Boeing is all-in on the bridge tanker project.
“Boeing is 100 percent committed to the Air Force program,” he said. “We eagerly want to look at what their requirements are, where they want to go with it, and we’re ready to compete for it.”
While the company has had to work through issues with the KC-46, Hafer believes it is still in an advantageous position.
“The issues are being retired with the KC-46,” he said. “The Air Force is having a hand in developing the solutions. … That really plays to our strengths. The Air Force knows exactly what it’s getting and is actually helping design the future of the airplane.”
If the service were to go to with another contractor, that could create risk, he said. “They don’t know what the challenges are going to be with that other airplane,” Hafer added.
Waugh noted that past performance of contractors will play a part in a future bridge tanker acquisition decision.
“Our source selection process includes past performance, as well as technical evaluations,” he said. “We haven’t built the acquisition strategy or the source selection plan, but I anticipate that past performance would be one of the things we consider on any acquisition program, including the bridge tanker program.”