Narrative:

Stabilizer trim wheel was making a clunking noise at cruise when the autoplt trimmed. At top of descent, the wheel froze with the motor still running. Ran the checklist, turning of the automatic/main electrical trim. Diverted from pns to mco for WX and added runway length. Declared emergency. Began long slow descent to visual landing runway 18R mco. Controls were heavy and trim wheel required 2 pilot input to turn. Landing uneventful. Not knowing control forces required, we had flight attendants prepare cabin. Because of thunderstorms, we changed destination from pns to mco (long and dry). Callback conversation with reporter revealed the following information: reporter advised that discussions with maintenance the following day indicated they had lubricated the chain in the stabilizer trim drive mechanism and released the aircraft to service.

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Original NASA ASRS Text

Title: FLT CREW OF B734 EXPERIENCED JAMMED STABILIZER TRIM AT TOP OF DSCNT. UTILIZED ABNORMAL PROCS CHKLISTS AND DIVERTED TO MCO DUE TO LONGER RWYS AND BETTER WX.

Narrative: STABILIZER TRIM WHEEL WAS MAKING A CLUNKING NOISE AT CRUISE WHEN THE AUTOPLT TRIMMED. AT TOP OF DSCNT, THE WHEEL FROZE WITH THE MOTOR STILL RUNNING. RAN THE CHKLIST, TURNING OF THE AUTO/MAIN ELECTRICAL TRIM. DIVERTED FROM PNS TO MCO FOR WX AND ADDED RWY LENGTH. DECLARED EMER. BEGAN LONG SLOW DSCNT TO VISUAL LNDG RWY 18R MCO. CTLS WERE HVY AND TRIM WHEEL REQUIRED 2 PLT INPUT TO TURN. LNDG UNEVENTFUL. NOT KNOWING CTL FORCES REQUIRED, WE HAD FLT ATTENDANTS PREPARE CABIN. BECAUSE OF TSTMS, WE CHANGED DEST FROM PNS TO MCO (LONG AND DRY). CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR ADVISED THAT DISCUSSIONS WITH MAINT THE FOLLOWING DAY INDICATED THEY HAD LUBRICATED THE CHAIN IN THE STABILIZER TRIM DRIVE MECHANISM AND RELEASED THE ACFT TO SVC.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.