What was found
DURING DESCENT, ACFT EXPERIENCED A MC LIGHT AND SINGLE CHIME, IMMEDIATELY FOLLOWED BY THE AUTOPILOT DISCONNECT WARNING. FLT CONTROL CAUTION WAS ILLUMINATED ON THE CAP, AND A LOCAL PITCH TRIM ASYM LIGHT WAS NOTED ON THE INSTRUMENT PANEL. THE MC AND LOCAL ALERTS FLASHED SEVERAL TIMES, GIVING AN AURAL SC ALERT EACH TIME, BEFORE FINALLY ILLUMINATING FOR GOOD. NOTIFIED ATC THAT ACFT HAD A COMPLETE PITCH TRIM FAILURE, AN EMERGENCY WAS DECLARED. AN UNEVENFUL, VISUAL APROACH (BACKED UP WITH ILS COUPLED FD) AND LANDING WAS ACCOMPLISHED.