One of the issues was wiring harnesses being too close together. The USAF has higher requirements in for redundancy and fault-tolerance in aircraft that may be

One of the issues was wiring harnesses being too close together. The USAF has higher requirements in for redundancy and fault-tolerance in aircraft that may be shot at than civilian airliners do, go figure. Either way, it's not something that should be new for a company like Boeing that's done several generations of airliner to tanker conversions.