EMB ERJ 145 ER/LR
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Troubleshooting
Aircraft Equipment Problem Critical
Flight Crew Regained Aircraft Control; Flight Crew Returned To Departure Airport; Flight Crew Landed in Emergency Condition; Flight Crew Diverted
Aircraft
After a normal takeoff from Runway 27 we were on runway heading when we reached FRA (Flap Retraction Altitude) so I requested flight level change Flaps to zero when the speed began to increase and then after takeoff check per usual. It was about this time that I began to feel a little extra nose up pressure so I put in some nose down trim and the pressure went away. Shortly after this we were given a turn to 120 degrees and contacted departure. During the turn I began to feel more nose up pressure and realized I was pushing down on the yoke when I normally would have to pull up a little due to the loss of lift during a turn. I proceeded to add some nose down trim which helped some but the nose up pressure came back. By now we had checked in with departure and were given a climb to 10;000 feet. By this point we had almost accelerated to 240 and nose up force was getting worse so I added some more trim. It was at this point that I looked down at the EICAS (Engine Indication and Crew Alerting System) where the trim indicator was and after putting in some nose down trim noticed that after going down initially it started to go back up again slowly. It was at this point that I confirmed in my mind that something was wrong and suspected a pitch trim runway. I then advised the Captain that I think we have a pitch trim runaway and proceeded to hold down the red button on the yoke. I don't think he realized the gravity of what was going on until pitch trim primary and back INOP appeared on the EICAS in red. At this point he ran the IAI for pitch trim runaway. I was already doing what it said to do so he ran the QRH (Quick Reference Handbook) for pitch trim runaway. He then asked me if the pressure was excessive or not and at that point it wasn't. So he proceeded to follow the QRH and shut down the main and backup trim. By this point we had reached 10;000 feet and had notified ATC that we had a problem. They asked us if we wanted priority handling and the Captain said yes. Once we leveled off the control forces started to take their toll on my arms and informed the Captain that the forces were now excessive and so he followed the QRH instructions for that alternative. That required landing at nearest suitable alternate and disabling the main pitch trim. So he did that and we were able to regain backup pitch trim. We then requested a landing back at ZZZ on Runway 27. We landed flaps 22 and taxied to the gate with an escort of fire trucks. We found the QRH for runway pitch trim to be a little confusing. It also made us jump around a lot flipping or different pages based on whether the forces were excessive or not. The QRH initially said to turn off both pitch trim systems if control forces weren't excessive instead of switching to the backup. We were also confused as to the use of spoilers and flaps. One page said not to use them and another said it was ok. The Captain spent several extra minutes trying to figure out what to do.
EMB-145 flight crew reported experiencing a Runaway Pitch Trim.