Emb-135LR first officer reported diverting to an alternate after experiencing difficulty controlling...

Narrative:

The captain and I were cleared to 'descend via' the arrival and the plane suddenly rolled to the right at a very rapid rate and pitched down as well. I immediately pressed the 'quick disconnect' button and held it. The captain said; 'that's just wake' and then I told him it put us in a nose low trimmed attitude. The plane was in a nose down trim and maintaining altitude was not possible and we continued to descend. The captain alerted ATC that we were still descending and wouldn't be able to make the altitude gates. The master warning messages for both the main and backup trim were present. The captain ran the QRH while I continued to fly the plane. After the reset was unsuccessful we [advised ATC] and asked to get direct to nearest airport and they gave us a vector [to the alternate airport] for the ILS. We set up the approach and briefed it accordingly. My arms and thumb were worn out and fatigued so the captain relieved me and continued the approach to landing via an ILS in IMC. The training I received in initial was crucial for the happy outcome in this event. I would encourage the training department in recurrent to give this problem without pre-briefing it so that it gets ingrained how quick and dangerous it is.

Original NASA ASRS Text

Title: EMB-135LR First Officer reported diverting to an alternate after experiencing difficulty controlling the aircraft when the stabilizer pitch trim failed in the nose down position.

Narrative: The Captain and I were cleared to 'Descend Via' the Arrival and the plane suddenly rolled to the right at a very rapid rate and pitched down as well. I immediately pressed the 'quick disconnect' button and held it. The Captain said; 'That's just wake' and then I told him it put us in a nose low trimmed attitude. The plane was in a Nose Down trim and maintaining altitude was not possible and we continued to descend. The Captain alerted ATC that we were still descending and wouldn't be able to make the altitude gates. The Master Warning messages for both the main and backup trim were present. The Captain ran the QRH while I continued to fly the plane. After the reset was unsuccessful we [advised ATC] and asked to get direct to nearest airport and they gave us a vector [to the alternate airport] for the ILS. We set up the approach and briefed it accordingly. My arms and thumb were worn out and fatigued so the Captain relieved me and continued the approach to landing via an ILS in IMC. The training I received in initial was crucial for the happy outcome in this event. I would encourage the training department in recurrent to give this problem without pre-briefing it so that it gets ingrained how quick and dangerous it is.

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.

Attributes
ACN	1411822
Time
Date	201612
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	EMB ERJ 135 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Horizontal Stabilizer Trim
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical

Emb-135LR first officer reported diverting to an alternate after experiencing difficulty controlling the aircraft when the stabilizer pitch trim failed in the nose down position.