Northwest Airlines Flight 85 was a scheduled international passenger flight from Detroit Metropolitan Wayne County Airport in the United States to Narita International Airport in Japan. On October 9, 2002, while over the Bering Sea, the Boeing 747-400 experienced a lower rudder hardover event, which occurs when an aircraft's rudder deflects to its travel limit without crew input. The 747's hardover gave full left lower rudder, requiring the pilots to use full right upper rudder and right aileron to maintain attitude and course.