At the end of January, the U.S. Air Force downgraded two previously unreported Category 1 deficiencies related to the KC-46’s auxiliary power unit (APU), according to the head of Air Mobility Command.

The two deficiencies with the brand-new tanker’s APU are maintenance related, Air Mobility Command chief Gen. Jacqueline Van Ovost told reporters Feb. 1 during a Defense Writers Group event.

The first problem was with the APU’s duct clamps, which are used to join sections of the APU bleed duct, the APU supplying air, and the ducting inside the aircraft to the main engine, fuel system and cooling/heating system.

Van Ovost explained that the duct clamp was moving and was “causing some problems,” but the Air Force worked with Boeing and the company engineered a fix.

“They now only found the fix and tested it, but about 70% of the fielded fleet have already been retrofit and the rest will be done very shortly,” she said. “We’re confident that the clamp fix is the final fix based on their experience with the commercial aircraft and how it did the redesign on that.”

The second problem was with the APU’s drain masts, which are used to clear out condensation, fuel and oil from the aircraft. There were quality issues with the spot weld that could potentially cause a piece to break off the aircraft. Boeing has redesigned the drain masts and is working with the Air Force through the retrofit option, Van Ovost said.

Separately, the Air Force does not plan to increase the acceptance rate of the KC-46 to more than two aircraft a month because it is not operationally tasking the new tankers. “For right now, I don’t need to be in a hurry to take them at a faster rate than about two a month, Van Ovost said.

The service anticipates the fix for the tanker’s Remote Vision System will come online in late 2023.