EMB-145 flight crew reported an EICAS Message PTRIM MAIN INOP while preflighting. Maintenance corrected the issue and pre-flight continued. During push back; the flight crew noticed that the pitch trim was making an un-commanded full nose down and full left roll trim. The aircraft returned to the gate for additional maintenance and the flight was cancelled.
Synopsis
EMB-145 flight crew reported an EICAS Message PTRIM MAIN INOP while preflighting. Maintenance corrected the issue and pre-flight continued. During push back; the flight crew noticed that the pitch trim was making an un-commanded full nose down and full left roll trim. The aircraft returned to the gate for additional maintenance and the flight was cancelled.
Narrative
While conducting IOE on a new First Officer (FO) student we were almost done with the setup when we got an EICAS Message PTRIM MAIN INOP. Went through normal steps; had contract Maintenance come out and they subsequently did a system reset of the trim system and conducted a satisfactory test. Everything was signed off and good to go. We set the plane up and were just about to push back when my student noticed that the Pitch Trim was making an un-commanded full nose down and full left roll trim. We did a quick check to make sure that neither of us were touching anything at the time and after the previous Maintenance issue I was very suspect of the trim system. In the Maintenance pages in the Multi-function Flight Display (MFD) there had been a MAIN PITCH TRIM FAIL on this day and on Day 0 a BACKUP PITCH TRIM FAIL. We wrote it up and the flight was cancelled. I am no engineer but after seeing the history of trim issues on this aircraft and through conversations with Maintenance who read deeper into its trim history I cannot help but feel that maybe this system should have been replaced earlier. Having experienced both of these failures separately in the simulator before and seen the results I can't help but feel that Maintenance history of a flight control system should be immediately removed and diagnosed outside the aircraft.
Second reporter narrative
During preflight setup; a Pitch Trim INOP Warning Message appeared on EICAS. The Captain wrote up the failure and contacted Maintenance. After Contract Maintenance came to fix a Main PTRIM INOP and test; we began preparing for push back. Just prior to push back I noticed the aircraft begun an un-commanded full left roll and full nose down pitch condition. Checking to ensure neither of us were touching or commanding the pitch or roll condition; the Captain wrote up the anomaly and called Maintenance. Maintenance was called out and replaced the Pitch Trim Module and the aircraft was ferried back to ZZZ1 the next day.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.