What was found
SHORTLY AFTER TAKEOFF, PRI STAB TRIM FAIL AND AP FAIL CAS MESSAGES ILLUMINATED, THEN WE EXPERIENCED A NOSE-UP TRIM RUNAWAY, COUPLED WITH A TRIM SW FAULT L CAS MESSAGE. AIRPLANE WAS BARELY CONTROLLABLE WITH TWO PILOTS ON THE CONTROLS. RETURNED FOR EMERGENCY LANDING. REMOVED AND REPLACED THE L/R AUTOPILOT DISCONNECT SWITCHES IAW CE680A AMM 22M 10-50, OPERATIONAL CHECKS ARE GOOD AT THIS TIME. NO FURTHER DEFECTS NOTED.