UPDATED: To include comments from Gen. Stephen Lyons, TRANSCOM chief, and industry analyst Richard Aboulafia of Teal Group.

WASHINGTON: Boeing’s troubled KC-46 tanker program now must fix a Category 1 deficiency for leaks in the fueling system, the Air Force has announced. That means the problem could cause death, loss of the aircraft, render the aircraft incapable of performing its mission or stop the aircraft from completing testing. Boeing, per its contract, must use its own money to fix this problem.

The Air Force provided few details about the latest problem bedeviling the airborne tanker in its terse statement last night, saying only that it had “upgraded an existing deficiency of its KC-46 Pegasus fuel system to Category I. The Service’s KC-46 Program Office first identified excessive fuel leaks in July of 2019 after an air refueling test.”

Boeing offered a few more tidbits in a statement provided by a spokesman: “The U.S. Air Force discovered several KC-46 aircraft requiring fuel system repairs. The KC-46 fuel system is equipped with redundant protection for fuel containment. In some cases with this issue, aircraft maintenance crews are finding fuel between the primary and secondary fuel protection barriers within the system.”

This is the fifth Category 1 deficiency finding the supposedly low-risk KC-46 program has racked up. The most recent was announced in September for cargo restraint locks on the cabin floor that came unlatched during flights, prompting the Air Force to prohibit the plane from carrying cargo and passengers. The problem was fixed in December, and the Air Force lifted the ban.

Indeed, Air Force Chief of Staff Gen. David Goldfein admitted to the Senate Armed Services Committee in testimony earlier this month that because of continuing “profound problems,” he would not put the KC-46 tanker into service unless it was needed in a “high-end fight” with peer competitors — basically, war with Russia or China.

One of the tanker’s highest-visibility issues is the long-standing inadequacy of the crucial Remote Vision System (RVS), a set of sensors and cameras which allows the boom operator to connect the tanker to the plane that needs gas. The RVS has a dangerous blind spot that could cause the refueling boom to crash into the client aircraft.

Air Force acquisition czar Will Roper told reporters last Friday that he is hopeful that a deal with Boeing on an agreed fix to the RVS would be sorted out soon, but wouldn’t give an expected date for fixes to be started.

The Air Force was similarly opaque in its statement last night about what measures are being set up to fix the fuel leakage problem, and did not state whether the production line has been shut down — although that is common in Category 1 violations.

“The Air Force and Boeing are working together to determine the root cause and implement corrective actions. The KC-46 Program Office continues to monitor the entire KC-46 fleet and is enhancing acceptance testing of the fuel system to identify potential leaks at the factory where they can be repaired prior to delivery.”

Boeing says that it has begun fixing aircraft and already has repaired an undisclosed number of Pegasus aircraft: “We are disappointed to learn of this development and are already implementing assembly and installation improvements to correct the issue. We have repaired several of the airplanes, and will continue to implement repairs as needed. Boeing is working with the utmost urgency to address this issue.”

Neither the service or the company has speculated about how long of delay the issue might cause to delivery of the aircraft.

UPDATE BEGINS. Richard Aboulafia, aircraft industry guru with Teal Group, told me today that it’s hard to predict the schedule impact. “Since this was an existing problem that’s been elevated in importance, they might have already had a roadmap to fix it,” he said. “But given this platform’s difficult history as a problem child, it’s probably further evidence that this fleet will be late to replace older platforms.” UPDATE ENDS.

The idea of an even longer KC-46 delivery delay likely is giving Transportation Command head Gen. Stephen Lyons an even bigger headache than he already has from worrying about a growing gap in tanker capability.

Lyons, in the command’s annual unfunded priorities list to Congress sent to Congress in February, said aerial refueling is his “number one priority.” He expressed serious concerns that Air Force plans to cut 10 KC-10 and 16 JC-135 tankers prior to the KC-46’s availability in 2023 would “create a capacity bathtub with significant impacts to Combatant Command daily competition and wartime missions.”

UPDATE BEGINS. Speaking to reporters today, Lyons was reluctant to directly discuss the current situation with KC-46, noting that it is the subject of ongoing negotiations between the Air Force and Boeing. However, he said he is optimistic that TRANSCOM is nearing “a good bridging” solution to resolve the current capacity gap.

“I believe we’re making progress with the Air Force and Congress to ensure we retain taskable capability for the combatant command to support the joint force,” he said. “Things are much more optimistic here of late.” UPDATE ENDS.