SEOUL, South Korea — The U.S. military says a KC-135 refueling aircraft supporting operations against Iran crashed in western Iraq , killing four of its six crew members. The U.S. Central Command , which oversees the Middle East, said the crash followed an unspecified incident involving two aircraft in “friendly airspace,” and that the other plane landed safely. Here’s what is known so far about the tanker, which is the fourth publicly acknowledged U.S. aircraft to crash during the war against