What was found
PDIS 592 27-40 6412 13MAY21 KIX OPEN U LOGPAGES:383476 AFTER T/O IN A TURN RECIEVED LEVEL 2 STAB OUT OF TRIM ALERT - DISCONNECTED AP CLEARED WING UP VERY HEAVY ON PITCH CONTROL - NOTICED STAB TRIM STUCK AT 8.0 ( T/O TRIM ) AND DID NOT MOVE YOKE TRIM SW OR SUITCASE HANDLES - DECLEARED TO RTB - DECLEARED EMERGENCY - DAMPED FUEL IN RADER HOLDING PATTERN - STAB REMAINED AT 8.0 THRU LANDED AND BLOCK IN. SHGN 13MAY21 04:01 KIX U CHECKED STAB TRIM FUNCTION PER AMM 27-44-04-5. SEEMS TO BE MECHANICAL FUSE PIN BROKEN IN CHAIN DRIVE UNIT. PART NIS KIX. MPN: AJH7378-1 CPN: 0047594 QTY: 1 REPLACED HORIZONTAL STAB CHAIN DRIVE UNIT FUSE PIN AND REINSTALLED CHAIN DRIVE UNIT PER AMM 27-44-06-4. NEED ADJUST CHAIN TENSION. TENSION METER NOT AVAIL AT THIS TIME. PERFORMED HORIZONTAL STABILIZER DRIVE CHAIN ADJUST AND WITHIN LIMIT. ALSO INSPECTED ACME DRIVE, DRIVE CHAIN, JACK SCREW AND OTHER RELATED COMPONENTS AND NO DEFECT FOUND.