As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT CREW REPORTS CO-PILOT TRIM QUIT WORKING AT APPROX 5000' AGL, RECEIVED AN ELEVATOR SPLIT MASTER WARNING. ENGAGED AUTOPILOT AC BEGAN PORPOSING, DISCONNECTED TO AP, DISCONNECTED THE ELEVATOR TRIM AND DECLARED AN EMERGENCY AND RETURNED TO THE CITY OF ORIGIN. FLIGHT 5001. OPEN