Narrative:

Normal preflight and taxi leading up to the event. This was the captain's leg and it was a left seat departure. On departure from we were given a turn to the southwest. At roughly 1;700 MSL I noticed the PF/PIC reach to apply rudder trim. Immediately after I felt the aircraft yaw strongly to one side. I looked down and saw the rudder trim was full to the right and the ball of the slip-skid indicator was almost fully deflected. The PF/PIC corrected the condition with manual rudder input. It became quickly apparent the rudder trim had malfunctioned and the knob was stuck. The pm/sic requested to level off at 3;000 while we ran the appropriate checklist ('rudder trim runaway'). Controls were transferred to the sic and we ran the checklist which did not remedy the situation. We were advised the MSA in the area was 2;600 MSL. At roughly this point; we [advised ATC] we would like vectors back to ZZZ for an ILS approach. Controls were transferred back to the PIC. The appropriate standard checklists and flows were accomplished and we landed with heavy rudder input in ZZZ without incident. We were able to taxi into the gate under our own power. Upon shutting down; company was advised.

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Original NASA ASRS Text

Title: DHC-8 flight crew reported a rudder trim runaway shortly after takeoff prompting a return to the departure airport.

Narrative: Normal preflight and taxi leading up to the event. This was the captain's leg and it was a left seat departure. On departure from we were given a turn to the southwest. At roughly 1;700 MSL I noticed the PF/PIC reach to apply rudder trim. Immediately after I felt the aircraft yaw strongly to one side. I looked down and saw the rudder trim was full to the right and the ball of the slip-skid indicator was almost fully deflected. The PF/PIC corrected the condition with manual rudder input. It became quickly apparent the rudder trim had malfunctioned and the knob was stuck. The PM/SIC requested to level off at 3;000 while we ran the appropriate checklist ('rudder trim runaway'). Controls were transferred to the SIC and we ran the checklist which did not remedy the situation. We were advised the MSA in the area was 2;600 MSL. At roughly this point; we [advised ATC] we would like vectors back to ZZZ for an ILS approach. Controls were transferred back to the PIC. The appropriate standard checklists and flows were accomplished and we landed with heavy rudder input in ZZZ without incident. We were able to taxi into the gate under our own power. Upon shutting down; company was advised.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.