Flight Crew Commercial
Human-Machine Interface
Aircraft Equipment Problem Critical
Flight Crew Returned To Departure Airport
Aircraft
At about 4;000 FT in the initial climb the rudder trim went full left uncommanded causing the plane to yaw. The Captain then tried to correct and then the rudder trim went full right uncommanded. We immediately notified ATC and returned to our departure airport. The Captain was the pilot flying and the autopilot was not engaged.
The reporter clarified his report to advise the full scale deflections were 'momentary' and stated he 'believed' there was an actual full scale deflection of both the rudder trim indices and the rudder trim itself but was unable to describe the actual flight control response and the opposing input required by the Captain (the pilot flying) to maintain an in trim condition.
The flight crew of a CRJ-700 returned to their departure airport after experiencing uncommanded full travel rudder trim to both the left and right.