There’s a new problem with Boeing’s KC-46 tanker

DAYTON, Ohio—The troubled KC-46 tanker has yet another problem Boeing has to fix on its own dime, the Air Force said Tuesday.

It’s in the engine: vibrations from the fuel pump are damaging the tanker’s air ducts, said Kevin Stamey, program executive officer for mobility and training aircraft. Air ducts serve multiple purposes, including pulling air from the engine to cool off the plane’s subsystems. 

“Boeing has been quick to get those repairs done to the damaged aircraft. We just flight-tested the workaround for that and the initial flight test results look very promising, and we're actually on the path to quickly downgrade that one,” Stamey told reporters at the Air Force’s Life Cycle Industry Days conference here. 

The temporary fix entails cycling the fuel pump on and off so the damage from the vibration is minimized, Stamey said. The company will likely have to redesign the fuel pump to fix it permanently, he said. 

Still, Stamey said the timeline for getting it fixed will be “relatively short” compared to other “category one” deficiencies—problems that could crash an aircraft or otherwise cause loss or death.

A Boeing spokesperson said, “A long-term fix is in work, and we have developed a short-term mitigation plan that is being reviewed by the U.S. Air Force to reduce impact to the fleet. This is not an immediate safety concern.”

The KC-46 program already had six other category one deficiencies.

One of the main problems that has plagued Boeing’s tanker is its Remote Vision System, which allows the boom operator to see the boom through a video feed. The aircraft does not have a window for direct viewing, like other tankers. 

Boeing is working to upgrade the refueling camera system through a redesign, called RVS 2.0, but the effort has been delayed two years, and not set to arrive until spring 2026. The new remote vision system will fix two of the aircraft’s seven category one deficiencies. Another unresolved problem is with the tanker’s “stiff boom,” which has prevented the tanker from refueling A-10s. 

While the schedules have slipped for both the new vision system and the stiff boom, prototypes for fixes are being tested in the labs now, and the program is making “good progress,” Stamey said. 

The tanker’s other three deficiencies have to do with production quality, and are close to being resolved, Col. David Holl, senior materiel leader for the KC-46 program, said Tuesday. 

Asked about Boeing’s struggle with production quality, Stamey said the company has been proactive about these problems and added quality inspectors to its production lines. 

“They've added inspectors if they discover one, they lean forward and they tell us. They've actually called and said, Hey, we have something. We're not going to deliver an aircraft next week until we go back and verify, was this a one off, or is this something that flowed back into production?” Stamey said. 

The mounting problems have racked up a hefty bill for Boeing: losses on the KC-46 program top $7 billion.