Sept. 16 (UPI) -- The U.S. Air Force barred its KC-46 tanker planes from carrying cargo or passengers until a problem with cargo locks is resolved.
The planes, made by Boeing Co., were found to have malfunctioning locks on the aircraft's floor, potentially causing heavy cargo to suddenly move unrestrained around the interior of the aircraft.
The Air Mobility Command revealed the deficiency on Sept. 11, citing an incident in which cargo restraint devices broke open during an operational test and evaluation flight. Although locks were fully installed and inspected, they nonetheless malfunctioned.
"As a result of this discovery, the Air Force has submitted a Category 1 deficiency report [a reference to a serious technical issue that could endanger the plane and its crew] and is working with Boeing to identify a solution," Air Force Mobility Command spokesman Col. Damien Pickart said in a statement. "Until we find a viable solution with Boeing to remedy this problem, we can't jeopardize the safety of our aircrew and this aircraft."
On Friday, Boeing Co. said in a statement that its team, working with the Air Force, is making progress in resolving the issue.
"The company and the Air Force are cooperatively analyzing the locks to determine a root cause," Boeing stated. "The safety of KC-46 aircraft and crew is our top priority. Once a cause has been identified, the tanker team will implement any required actions as quickly as possible."
Boeing has a fixed-priced contract with the Defense Department by which it is responsible for costs over the $4.9 billion specified in the contract, and thus far has spent $3.5 billion of its own money correcting technical problems of the KC-46 plane.
The company redesigned the remote vision system, by which operators of the plane's remote fuel boom can watch activities without use of a window or other visual cue, and has dealt with multiple examples of debris found in planes after they were delivered to the Air Force.
The Air Force plans to buy 179 KC-46s from Boeing, and 52 are currently on contract. Eighteen have been delivered.