WASHINGTON — The U.S. Air Force risks repeating its previous mistakes on the KC-46A Pegasus program by planning to accept a redesign of its troubled Remote Vision System without taking the right precautions, the Government Accountability Office said.

In a report released Thursday, GAO said the Air Force’s plan to accept the financial responsibilities of the vision system’s redesign could put the service at risk of incurring more costs and delays, if it finds out later the system needs further redesigns.

“These choices mirror those made during the development of the KC-46 that led to the delivery of an aircraft that did not fully meet its requirements, and the Air Force stands poised to potentially repeat its past mistake,” GAO said.

The Boeing-made aerial refueling tanker, which is eventually meant to replace one-third of the service’s legacy fleet of aging tankers, has a problematic vision system that makes it hard for the boom operator to clearly see the receiving aircraft’s refueling receptacle in some lighting conditions. This has sometimes led to the boom making undetected contact with the aircraft being refueled and damaging its coating.

Boeing in 2020 signed a memorandum of agreement with the Air Force to design a new vision system to address those problems, dubbed RVS 2.0, which is expected to be finished by mid-2024. Boeing is also updating the existing system along the way.

But GAO expressed concern about the Air Force’s plan to assume financial responsibility for the new vision system’s design without making sure the program is taking steps to ensure its critical technologies are mature.

GAO said that KC-46 program plans to commit to “an immature design” for the new vision system, without setting up its own technology readiness assessment and a plan to mature the critical technologies involved.

GAO also criticized the KC-46 program for not planning to test a prototype of the revised system in flight before the design is finished, which it said could lead to the discovery of new problems.

The memorandum of agreement said the Air Force would be financially responsible for any design changes that are made after the preliminary design review is finished.

A KC-46 Pegasus from the 97th Air Mobility Wing, assigned to the 56th Air Refueling Squadron, Altus Air Force Base in Oklahoma, refuels an F-16 Fighting Falcon on December 7, 2020. The KC-46 has been approved to refuel all variants of the F-15 Eagle and F-16 during U.S. Transportation Command-tasked missions.

“This arrangement, effectively, reversed the original terms of the firm-fixed price contract that aimed to hold Boeing fully responsible for delivering a system that would work in any lighting conditions,” GAO wrote.

The Air Force told GAO that this was necessary because the service and Boeing had reached an impasse on how to address the vision system’s problems, and who would be financially responsible.

GAO said Air Force Secretary Frank Kendall should order the KC-46 program to complete its own technology readiness assessment before, or soon after, closing the preliminary design review, to ensure it understands how mature the system’s critical technologies are.

GAO also said Kendall should order the program to develop technology maturation plans for the critical technologies, and to test a full prototype of the new vision system on a Pegasus in an operational environment before closing the design review, or soon afterward.

The Air Force has not yet accepted the completed design of RVS 2.0, months after the review was expected to be completed.

In a written response to GAO, the Air Force disagreed with the agency’s recommendations. The Air Force said that the vision system program is on track to meet or exceed all but one contract requirement, and a plan for fixing that requirement is being developed.

Boeing referred a request for comment to the Air Force.

The Air Force and Boeing signed a fixed-price incentive development contract for the KC-46 that limits the government’s liability up to a $4.9 billion ceiling, after which Boeing assumed responsibility for all additional overrun costs.

Boeing has repeatedly paid the Air Force hefty charges related to the KC-46 program. On Wednesday, Boeing announced the latest charge — for $402 million, bringing the total tally to about $5.4 billion — which it attributed to the vision system and pandemic-related problems.

The vision system includes a pair of cameras for the boom operator to guide the boom into the receiving aircraft; a pair of long-wave infrared boom cameras for use in darkness; and a primary display that projects a 3D image of the receiving aircraft to the boom operator, who is seated at a station near the Pegasus’ cockpit. The boom operator then is able to reposition the boom and guide it in. The vision system is also used for hose-and-drogue refueling.

The KC-46 contract required Boeing to deliver a vision system that would work in all lighting conditions, but from the start it had problems with glare at certain sun angles. Boom operators also had difficulty making out the difference between the tip of the refueling boom and the receiver aircraft at night when using the infrared camera. And boom operators also don’t get enough depth perception with the vision system in some lighting conditions, leading to the unwanted contacts with the receiving aircraft.

The Pegasus’ vision system is meant to be an improvement over the system used in older tanker models, in which boom operators sit or lie face down to watch the boom and receiver aircraft through a window in the plane’s belly.

Three of the KC-46′s seven critical deficiencies are related to its aerial refueling system — two stemming from the vision system and one involving a problem with excessive stiffness in the boom — and fixing them will delay a decision on full-rate production until at least September 2024, nearly four years after it was originally expected to meet the milestone.

The KC-46′s seven critical deficiencies, all together, are expected also add almost $1 billion in cost growth, GAO said. But even before they are all likely to be fixed in 2024 and testing on fixes to the vision system and boom is finished, the Air Force will already have procured at least 118 aircraft out of the 175 production aircraft.

The Air Force touts the KC-46′s capability to refuel about 70% of the aircraft that might need air refueling support on U.S. Transportation Command missions — most recently adding the AC-130J Ghostrider, MC-130J Commando II, E-3G Sentry and C-5M Super Galaxy aircraft to its portfolio.

But GAO said at the moment, the KC-46 can only be used to refuel under certain conditions, and is now primarily being used to train aircraft and refueling crews. The service plans to use partially capable KC-46s for day-to-day aerial refueling needs to allow it to retire some legacy planes, but is also studying whether it should contract out for additional refueling capacity. That study should be done by next year, GAO said.

Stephen Losey is the air warfare reporter for Defense News. He previously covered leadership and personnel issues at Air Force Times, and the Pentagon, special operations and air warfare at Military.com. He has traveled to the Middle East to cover U.S. Air Force operations.

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