FLC OF MDT TURBOPROP DECLARED EMER DURING FINAL APCH WHEN THE CARGO FIRE WARNING LIGHT CAME ON. THE FIRE EXTINGUISHER WAS DISCHARGED UPON THE SECOND TIME THE LIGHT CAME ON AND IT WENT OUT. AFTER LNDG; NO EVIDENCE OF FIRE COULD BE FOUND.

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WHILE ON A VISUAL APCH TO RWY 13R AT DFW; I WS PF WHEN WE NOTICED THE CARGO FIRE LIGHT COME ON MOMENTARILY. THE CAPT WAS ABOUT TO BLOW THE #1 FIRE EXTINGUISHER IN THE CARGO DEPT WHEN IT CAME ON AGAIN. IT EXTINGUISHED IMMEDIATELY WHEN THE FIRE EXTINGUISHER WAS DISCHARGED. WE DECLARED AN EMER AND ASKED FOR FIRE TRUCKS TO MEET US WHEN WE STOPPED. WE LANDED UNEVENTFULLY AND WERE MET BY THE FIRE DEPT ON THE HIGH SPD TXWY ON A4 FACING E. PRIOR TO LNDG; WE HAD COMPLETED THE EMER MEMORY ITEMS AND CONSULTED THE QUICK REF CHKLIST TO INSURE WE DIDN'T FORGET ANYTHING. THE FLT ATTENDANT WAS IN COM WITH THE CAPT BEFORE WE LANDED AND WAS ABLE TO CHK THE BACK BULKHEAD FOR HEAT OR EVIDENCE OF SMOKE. THERE WAS NO EVIDENCE OF EITHER; SO WE PLANNED ON A NORMAL PAX DEPLANING ONCE STOPPED. WHEN WE CAME TO A FULL STOP; THE CAPT SHUT DOWN #1 ENG. THE FIRE DEPT PROCEEDED TO INSPECT THE ACFT AND CARGO AREA FOR FIRE. A FIREMAN CAME ON BOARD AND NOTIFIED THE CAPT THERE WAS NO EVIDENCE OF SMOKE/FIRE. WE THEN SHUT DOWN #2 ENG AND DEPLANED ALL THE PAX. THE FLT ATTENDANT DID A HEAD COUNT AND INSURED NONE OF THE PAX WERE INJURED DEPLANING. OUR COMPANY PAX SVC AND MAINT WERE NOTIFIED. THERE WAS NO DAMAGE TO THE ACFT OR INJURIES AS A RESULT OF THIS INCIDENT. THE CAUSE OF THE SMOKE LIGHT REMAINS AN UNSOLVED MYSTERY. ONE POSSIBLE CAUSE MAY HAVE BEEN FROM THE CONDENSATION IN THE AIR CONDITIONING PACKS WHEN WE DSNDED INTO WARM; MOIST AIR CAUSING THE FALSE SMOKE ALARM. I CAN ONLY RECOMMEND THAT IF THIS CONDENSATION IS ANTICIPATED TO WARM BOTH PACKS SLIGHTLY PRIOR TO DSCNT; TO DRY OUT THE DUCTS AND WATER SEPARATORS. OUR CRM AND PROCS WORKED VERY WELL DURING THE ENTIRE ORDEAL. ALL ACTIONS AND COM BTWN THE CREW AND EMER PERSONNEL WERE CLR AND COMPLETE.