B737-300 HAS CARGO FIRE WARNING ON GND.

Narrative

AFTER ARRIVING AT GATE; I HAD COMPLETED THE LOGBOOK ENTRIES; THE COCKPIT DOOR HAD BEEN OPENED AND PAX WERE DEPLANING. WE HAD BEEN NOTIFIED OF A BROKEN SEAT TRAY ON SEAT 17A BY THE FLT ATTENDANTS. I WAS IN THE PROCESS OF PLACING A CALL TO DISPATCH ABOUT THE SEAT TRAY WHEN THE FIRE BELL SOUNDED. WE IMMEDIATELY LOOKED FOR THE SOURCE OF THE ALARM AND FOUND THE CARGO HOLD FIRE INDICATION DISPLAYING AN AFT CARGO FIRE. THE CAPT SILENCED THE BELL AND CALLED FOR THE QRH. THE CHKLIST STARTS WITH A NOTE TO VERIFY THE PROB WITH GND CREW IF THE ALARM SOUNDS ON THE GND. AT THIS POINT WE WERE AWARE OF AN ODOR IN THE COCKPIT AND COULD NOT SEE ANY GND CREW OUT OF THE COCKPIT WINDOW. BELIEVING THERE WAS A FIRE IN THE AFT CARGO HOLD; WITH PAX STILL ON BOARD; THE CAPT CALLED TO CONTINUE THE CHKLIST AND THE AFT CARGO HOLD FIRE BOTTLE WAS DISCHARGED. THE CAPT NOTIFIED THE FLT ATTENDANTS THAT WE HAD A FIRE INDICATION IN THE CARGO HOLD AND TO GET EVERY ONE OFF THE ACFT. HE THEN NOTIFIED ME HE WAS GOING DOWN TO THE RAMP TO CHK THERE WAS NO GND CREW IN THE CARGO HOLD. THE FLT ATTENDANTS QUICKLY DEPLANED THE REMAINING PAX AND LEFT THE ACFT. THE CAPT REBOARDED THE ACFT AND NOTIFIED ME THAT THERE WAS NOBODY IN THE HOLD AND THAT THE FIRE DEPT WAS ON THE WAY. WE CHKED THE ACFT WAS EMPTY AND EXITED THE ACFT TO THE RAMP. I NOTICED THAT THE REAR SLIDE L2 HAD BEEN DEPLOYED AND ONE FLT ATTENDANT AND A GROUP OF PAX WERE STANDING TOGETHER IN FRONT OF OPS. THERE DID NOT APPEAR TO BE ANY SIGN OF FIRE IN THE HOLD. THE FIRE DEPT CONFIRMED THAT THERE WAS NO FIRE. THE CAPT TOLD ME THAT THE FLT ATTENDANT ON THE RAMP HAD ACCOUNTED FOR HER PAX AND ASKED ME TO GO UPSTAIRS TO SEE IF THE FLT ATTENDANTS AT THE GATE COULD ACCOUNT FOR THEIR PAX. I PROCEEDED UPSTAIRS AND WAS TOLD BY BOTH FLT ATTENDANTS AT THE GATE THAT EVERYONE WAS SAFE; BUT SEVERAL PAX WHO HAD DEPLANED BEFORE THE ALARM SOUNDED; HAD LEFT. THE CAPT BEGAN MAKING CALLS ON HIS CELL PHONE TO NOTIFY COMPANY OF THE EVENT. AT SOME POINT I WAS GIVEN A PHONE WITH OPS ON THE LINE. OPS GAVE ME AN EXTENSION NUMBER AND TOLD ME TO CALL MAINT. WHEN I GOT THROUGH TO THAT EXTENSION I WAS TOLD THAT THE CAPT HAD ALREADY SPOKEN TO THEM. IT WAS MENTIONED THAT THEY THOUGHT FUMES FROM THE BELT LOADER AT THE REAR CARGO DOOR HAD BEEN BLOWN INTO THE HOLD BY THE STRONG WINDS AND HAD PROBABLY ACTIVATED THE FIRE SENSORS. I WOULD RECOMMEND THAT ANY INFO ON THIS TYPE OF EVENT BE PASSED ON TO FLT CREWS. HAD WE KNOWN EXHAUST FUMES COULD CAUSE THIS TO HAPPEN WE MAY HAVE BEEN ABLE TO IDENT THE ODOR IN THE COCKPIT AS EXHAUST FUMES BEING BLOWN IN THROUGH THE OPEN DOORS BY THE STRONG WINDS. THIS MAY HAVE CAUSED US NOT TO CONTINUE WITH THE CARGO HOLD FIRE CHKLIST UNTIL WE COULD VERIFY A CARGO HOLD FIRE. HOWEVER; WITH AN ODOR IN THE COCKPIT; A FIRE INDICATION AND PAX STILL ON BOARD. WE DECIDED PAX SAFETY WAS THE MAIN ISSUE AND CONTINUED THE CHKLIST.