Narrative:

Shortly after lift-off; the first officer informed me something was wrong as the aircraft wanted to slowly pitch up. We accelerated and cleaned up on schedule. I then took the controls. To maintain the aircraft's vertical trajectory; a very slight forward pressure was needed on the stick. When the stick was released; we noticed that the trim wheel was very slowly rotating with a nose up trim movement and the aircraft slowly pitched up. As soon as forward pressure was placed on the side stick; the trim wheel would reverse itself and slowly trim nose down. I decided that this was not something we wanted to experiment with on our way to ZZZ1 and decided to return to ZZZ. We used an ACARS message to inform dispatch; called ops on the radio; I briefed the four flight attendants on the interphone and made a brief PA to the passengers. We decided to not engage the autopilot as the aircraft was stable even with the need for slight forward pressure on the stick. We also weren't sure what the trim situation might be when the autopilot was disengaged for landing.we asked for and flew a ten mile final as we were slightly above landing weight. On short final; our weight was still showing 171;800 pounds. I decided a slight overweight landing was a better choice than the unknowns of a night missed visual approach. I also then realized I should have declared an emergency. We had a flight control issue! However; touchdown was at less than 100 feet per minute sink rate. We taxied normally to the gate.

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Original NASA ASRS Text

Title: A321 Captain reported the aircraft's autotrim malfunctioned during departure. The crew elected to return to the departure airport.

Narrative: Shortly after lift-off; the FO informed me something was wrong as the aircraft wanted to slowly pitch up. We accelerated and cleaned up on schedule. I then took the controls. To maintain the aircraft's vertical trajectory; a very slight forward pressure was needed on the stick. When the stick was released; we noticed that the trim wheel was very slowly rotating with a nose up trim movement and the aircraft slowly pitched up. As soon as forward pressure was placed on the side stick; the trim wheel would reverse itself and slowly trim nose down. I decided that this was not something we wanted to experiment with on our way to ZZZ1 and decided to return to ZZZ. We used an ACARS message to inform Dispatch; called Ops on the radio; I briefed the four Flight Attendants on the interphone and made a brief PA to the passengers. We decided to not engage the autopilot as the aircraft was stable even with the need for slight forward pressure on the stick. We also weren't sure what the trim situation might be when the autopilot was disengaged for landing.We asked for and flew a ten mile final as we were slightly above landing weight. On short final; our weight was still showing 171;800 pounds. I decided a slight overweight landing was a better choice than the unknowns of a night missed visual approach. I also then realized I should have declared an emergency. We had a flight control issue! However; touchdown was at less than 100 feet per minute sink rate. We taxied normally to the gate.

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.