As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER THE AUTOPILOT WAS ENGAGED THE PITCH TRIM COULD NOT BE CONTROLLED. IT KEPT PITCHING UP, EVEN WHEN THE TRIM WAS ALL THE WAY FORWARD. BOTH PILOTS HAD PUSH THE YOKE AT THE SAME TIME IN ORDER TO BE ABLE TO STOP THE PITCH UP AND CLIMB.