Northwest Flight 85On October 9, 2002, about 1740 Alaska daylight time, a Boeing 747-400 airplane, N661US, had a partial hydraulic system malfunction during cruise flight.
The flight was being conducted asFlight 85, by Northwest Airlines Inc, as an instrument flight rules (IFR) scheduled international flight under Title 14, CFR Part 121..
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The four flight crew members, fourteen flight attendants, and the 386 passengers, were not injured.The flight originated at the Detroit International Airport, Detroit, Michigan, about 1403 eastern daylight time, and was bound for the Narita International Airport, Tokyo, Japan.
During an interview with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on October 10, 2002, the captain said the airplane was at cruise altitude of approximately 35,000 feet with the autopilot engaged, when it abruptly rolled into a 30 to 40 degree left bank. He said there were indications that the lower rudder went to full left authority and remained there.
He said he declared an emergency and diverted the airplane to the Ted Stevens International Airport, Anchorage, Alaska.The captain said he and the first officer ran through several emergency procedures, but could not correct the problem.
He said as the airspeed decreased during the approach to landing, the lower rudder deflected further to the left. He said the rudder deflected left to a point where full right upper rudder and right aileron could no longer hold the airplane on course, and he used asymmetric engine thrust to maintain the correct heading.
The captain said after landing, he saw the lower rudder was still deflected fully to the left.