As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ELEVATOR TRIM TAB CONTROL HORN FAILED CAUSING ELEVATOR TO FLUTTER. FLUTTER WAS STOPPED BY REDUCING POWER, LOWERING LANDING GEAR AND FLAPS. APPEARS CONTROL HORN HAD BEEN CRACKED PREVIOUSLY THROUGH TWO-THIRDS OF ITS LENGTH. TRIM TAB HAD A CONSIDERABLE AMOUNT OF CORROSION. BETTER INSPECTION OF TRIM TAB AND CONTROL HORN.