The Air Force sees RVS 2.0 as a step toward autonomous tanker refueling, but until that comes to fruition, boom operators are still needed. Here, Senior Airman Jon Vermont and Staff Sgt. Jared Evans train Tech. Sgt. Joseph Deltoro on system operations during a KC-46 air-refueling mission. Senior Airman Ariel Owings
Photo Caption & Credits

GAO to Air Force: Think Twice Before Owning KC-46 Tanker Fix

Feb. 17, 2022

The Government Accountability Office wants the Air Force to do more testing and evaluation of Boeing’s fix for the KC-46 Pegasus tanker’s Remote Vision System (RVS) before proceeding with it, because the Air Force would be on the financial hook if it doesn’t work out.

In a new report released Jan. 27, the GAO said that Boeing’s fix for the RVS—one of a number of KC-46 deficiencies still being corrected—involves new technologies that may not yet be mature enough to move forward, posing a risk of cost and schedule growth. 

Boeing has eaten more than $5.4 billion in overruns on the Pegasus. The company took a charge of $406 million on the program in the last quarter of 2021 that pertain to the RVS. 

So far on the program, “the government’s financial risk has generally been limited to the ceiling price of its contract with Boeing,” the GAO said, but “the Air Force plans to close its review of the contractor’s proposed redesign and assume financial responsibility for it” without:

  • Assessing the system’s Technology Readiness Level (TRL);
  • Developing a plan to raise it to the appropriate TRL; and
  • “Integrating and testing the system prototype in an operational environment.” 

The GAO worries the Air Force will accept an RVS “that contains immature technologies and greater risk of cost and schedule growth.” The sooner the Air Force makes the technology assessments and fit-checks the system operationally, “the sooner it can identify design issues and proactively take steps to mitigate any further cost growth and delays in delivering promised capability.” 

The Air Force disagreed, saying it needs to take an accelerated approach to the RVS in order to field it at the “speed of relevance.” It also took issue with the GAO’s findings overall, saying the audit agency suggests the new RVS doesn’t work, when “the Air Force made extraordinary efforts to ensure the RVS 2.0 design will meet warfighter requirements.” The service said the system will provide “significantly enhanced capability to the warfighter” when deployed. The design is “on track to meet all but one relevant contract requirement,” and Boeing and USAF are working “collaboratively on a corrective action plan,” USAF said.   

The Air Force and Boeing are still working on “seven critical deficiencies,” which will delay the declaration of full-rate production on the KC-46 until “at least September 2024 and will contribute to nearly $1 billion” in cumulative cost growth, the GAO reported. However, the Air Force will have procured the majority of the planned 179 KC-46s “before the critical deficiencies are addressed” and full-rate production is declared, the audit agency said. 

Of the seven, two are related to the RVS. Among the others, one has to do with excessive stiffness in the refueling boom; one is a flight management system instability; one has to do with cracks in a drain tube, while another is about cracks in the drain mast, and the last has to do with fuel system leaks. Previous problems with cargo pallet locks detaching and air duct clamps cracking have been resolved. 

The deficiencies in the existing RVS, include the camera system—by which the boom operator, behind the cockpit, views the tanking operation. The system doesn’t deliver a clear picture of the boom as it makes contact with the receiving aircraft under all lighting conditions. This lack of clarity has caused some unintentional contacts with the receiving aircraft, which can damage the low-observable features of stealth aircraft.

Although the RVS is supposed to provide a “3D” image to the boom operator, depth perception also has been a problem. On the KC-135 and KC-10, the boom operator views the tanking operation directly, through a window. 

The Air Force is assuming more responsibility—and risk—for the program because it wants to go beyond the original requirements for the airplane. The RVS 2.0 is seen by the Air Force as a pathfinder for a future autonomous refueling system that won’t require a boom operator at all. When the Air Force asked for industry interest last summer in a KC-Y follow-on tanker, it said it’s interested in “autonomous” refueling. 

This will be especially important if a future “KC-Z” tanker is an uncrewed drone, although Air Mobility Command has been noncommittal about the requirements for that aircraft. Tanking autonomy could also reduce crew needs on the KC-46.   

The RVS 2.0 will allow the KC-46 to automatically see and identify an aircraft as it approaches the tanker, then configure the refueling system—boom angles, etc.—to match the approaching aircraft’s specific needs.   

The service and Boeing agreed to a cost-sharing arrangement on the new system, which corrects Boeing’s deficiencies but answers newly added service requirements. Boeing is releasing interim software updates on the way to the RVS 2.0. 

In disputing the GAO’s findings, the Air Force said its memorandum of agreement with Boeing on the RVS 2.0 allows a “nonstandard” approach to achieve an “accelerated timeline” to getting the capability fielded. The design was vetted “to a level of detail that exceeds” what would normally take place at a preliminary design review, USAF said. Moreover, the service said it’s “unlikely” that technical readiness assessment would discover “significant risks not already identified and tracked by the program,” and this step would probably add between six and 12 months to accomplish. That would be “either too late to affect the design” or delay RVS 2.0. 

USAF uses “a robust Risk, Issue, and Opportunity Management program,” with “tightly monitored Technical Performance Measures,” to obtain a solid understanding of the maturity of the critical technologies involved in RVS 2.0, the service said. 

The Air Force likewise disagreed with GAO’s recommendation to develop technology maturation plans for RVS 2.0 technologies, for the same reason: It would cause delay. 

There’s a “comprehensive plan” to burn down every “identified risk” in technology maturity, USAF said, and there are numerous reviews at various milestones to ensure this is happening. 

Finally, the Air Force disagreed that there should be testing of an RVS “full prototype” on the KC-46 in an “operational environment” prior to closing the Preliminary Design Review, saying this is “not practical.” The time it would take to get a prototype ready “is similar to the time necessary to get the first developmental test article.” Having to comply with this recommendation would add up to two years to the RVS fielding timetable, USAF said, and it’s unnecessary because “prototypes of the cameras have already flown,” with more flights already scheduled. 

The RVS 2.0 components have been tested in the laboratory and it’s been confirmed that the “flight environment will not result in degraded performance.” Besides, there will be the usual developmental and operational testing of the system, the Air Force said. 

Even so, the Air Force has decided not to close the Preliminary Design Review, service officials said, because the panoramic viewing system isn’t yet up to USAF’s comfort level.