B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Situational Awareness; Troubleshooting
Aircraft Equipment Problem Less Severe
Aircraft Automation Overrode Flight Crew; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; Flight Crew Took Evasive Action; General Maintenance Action
Aircraft
During initial climb Pilot Flying had to use 5 units left trim to center yoke; at initial cruise he had to use over 8 units left trim. Then trim kept moving to 15 units left trim; rudder and yoke did not move after 8 to 9 units. Captain said to return to the departure airport. I took over as pilot flying and landed overweight; no further incident.
A B737 First Officer reported the rudder trim required 5 units of left trim during climb but increased to 15 units at cruise with 8-9 unit of aileron trim. The flight returned to the departure airport.