The U.S. Air Force has added two new technical issues to the KC-46 tanker’s list of problems, potentially throwing a wrench into the projected delivery of the first tanker in October.

US based Defence Magazine Defence News stated that “both deficiencies are category-1 , the most serious designation of technical problems, and revolve around the tanker’s refuelling boom system. “

The Air Force is unsure whether the two problems will be solved in time for KC-46 manufacturer Boeing to deliver the first tanker next month.

The first new deficiency is labelled “No Indication of Inadvertent Boom Loads,” which refers to situations where boom operators unintentionally provide an input into the flight control stick that induces loads on the boom while it is in contact with a receiver aircraft. The KC-46 currently has no way to notify that operator that this is happening.

The second deficiency was found when pilots of receiver aircraft reported that the boom is too stiff during the part of the process when the receiver plane moves forward into the fuel transfer zone.

The Air Force can accept tankers at its own discretion, with or without active deficiencies. However, both Boeing and the Air Force have worked under the assumption that the service will not do so until all category-1 issues have been worked out or downgraded to category-2, which signifies that a workaround has been put into place.