Narrative:

Shortly after rotation on takeoff; the aural warning system sounded 'trim; trim' with an aural ding. No EICAS message was presented. The first officer reported to me that he did not use any trim; and I reported to him that I had not touched the controls. We continued to climb out on the departure. I noticed the first officer was struggling with the trim; pushing nose down with a lot of effort. We received multiple heading changes and altitude changes. At the same time I was trying to finish the takeoff checklist. My first officer told me he had no trim control; and that he had excessive nose up pressure. He asked me to try my trim; which I did; and it had no effect. We then knew the main pitch trim system was malfunctioning. We did not receive any messages on the EICAS; so I looked up the QRH section pertaining to flight controls. My first officer continued to struggle with the pressure. We both agreed that we should get the aircraft back on the ground as soon as possible. I then tried to find the QRH section that best pertained to our situation; but still unclear as to whether it was pitch trim runaway; or pitch trim inoperation. I tried to follow that later; since my first officer wasn't positive it was runaway; but he thought that it might be. I tried to follow the pitch trim inop QRH; but ran out of time to complete it. We were already being vectored onto approach; and I had to get the navigation equipment set up; and get the landing information. I did test the flight attendant; telling her of our situation; and that we were going back to land. We then landed uneventfully; and taxied to the gate with no further situations. During the approach; I assisted the first officer with the backup trim at his request. This worked very well.

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Original NASA ASRS Text

Title: EMB-145 Captain reported a possible pitch trim failure or runway trim during rotation with the First Officer flying. Flight returns to the departure airport.

Narrative: Shortly after rotation on takeoff; the aural warning system sounded 'trim; trim' with an aural ding. No EICAS message was presented. The FO reported to me that he did not use any trim; and I reported to him that I had not touched the controls. We continued to climb out on the departure. I noticed the FO was struggling with the trim; pushing nose down with a lot of effort. We received multiple heading changes and altitude changes. At the same time I was trying to finish the takeoff checklist. My FO told me he had no trim control; and that he had excessive nose up pressure. He asked me to try my trim; which I did; and it had no effect. We then knew the main pitch trim system was malfunctioning. We did not receive any messages on the EICAS; so I looked up the QRH section pertaining to flight controls. My FO continued to struggle with the pressure. We both agreed that we should get the aircraft back on the ground as soon as possible. I then tried to find the QRH section that best pertained to our situation; but still unclear as to whether it was pitch trim runaway; or pitch trim inoperation. I tried to follow that later; since my FO wasn't positive it was runaway; but he thought that it might be. I tried to follow the pitch trim inop QRH; but ran out of time to complete it. We were already being vectored onto approach; and I had to get the NAV equipment set up; and get the landing information. I did TEST the flight attendant; telling her of our situation; and that we were going back to land. We then landed uneventfully; and taxied to the gate with no further situations. During the approach; I assisted the FO with the backup trim at his request. This worked very well.

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.