B757 CREW DECLARES EMER AND LANDS BECAUSE OF SMOKE AND FUMES IN CABIN. SUSPECTED SOURCE WAS PA SYS PREVIOUSLY DEFERRED AS INOP BECAUSE OF CHRONIC PROBS.

Narrative

FOLLOWING A PLACARDING OF THE PA SYS ON THE ACFT; WHICH RESULTED FROM THE 7TH REPEAT WRITE-UP ON THAT SYS; WE DEPARTED DFW. DURING THE FINAL STAGES OF DSCNT INTO MIA; AND APPROX 16000 FT MSL DSNDING; WE BEGAN TO SMELL VERY STRONG BURNING ELECTRICAL FUMES. THE #1 FLT ATTENDANT CAME TO THE COCKPIT AND ADVISED US THAT EXTREMELY STRONG ELECTRICAL FUMES WERE FILLING THE CABIN; AND I ELECTED TO INITIATE THE SMOKE AND FUME CHKLIST AND EMER DSCNT CHKLIST; AND WE DECLARED AN EMER WITH MIA APCH. I ELECTED TO LAND TO THE E; EVEN THOUGH THE TFC WAS WESTERLY AT THE TIME -- WINDS WERE NOMINAL. FROM THE ONSET OF THE FUMES UNTIL BRAKES WERE PARKED ON THE TXWY; WAS ABOUT 6 MINS. DID NOT HAVE TIME TO BRIEF THE PAX; AND COULD NOT HAVE ANYWAY AS THE PA SYS WAS INOP. FIRE PERSONNEL INDICATED NO PRESENCE OF ANY SMOKE AFTER AN EXTERIOR INSPECTION. THEREFORE; ELECTED TO PROCEED TO THE GATE; AND REMOVE ALL ELECTRICAL PWR FROM THE ACFT IMMEDIATELY UPON OUR ARR. PARAMEDICS MET THE ACFT AND INTERVIEWED ALL PAX. MAINT REMOVED THE ACFT FROM SVC. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THIS WAS A LEGALLY DEFERRED ITEM PER THE ACR MAINT MANUAL; HOWEVER; NO CIRCUIT BREAKERS WERE PULLED WHEN THE INOP PLACARD WAS INSTALLED PER THE MANUAL. A 1.5 HR DELAY WAS TAKEN TO ATTEMPT TO REPAIR THE SYS. 2 AMPLIFIERS WERE REPLACED. IT WAS UNSUCCESSFUL. PROC FOR CONTACTING CABIN CREW WAS AN ASSIGNED NUMBER OF CHIMES DIFFERENT FROM THE NORMAL NUMBER USED. CABIN ANNOUNCEMENTS WERE GIVEN WITH EMER MEGAPHONES. SMOKE SOURCE WAS DETERMINED TO BE FROM OVERHEATED WIRING INSULATION IN THE CABIN CEILING. THE SYS WAS FOUND TO HAVE A DEAD SHORT. BECAUSE OF THE LACK OF COM WITH THE CABIN CREW; AND THE POTENTIAL PROBS THAT COULD CAUSE IN A FUTURE EMER; HE WILL NOT ACCEPT ANOTHER ACFT WITH THIS PROB. SUPPLEMENTAL INFO FROM ACN471070: A JUMP SEAT B727 CAPT VERIFIED THE STRONG ELECTRICAL SMELL. WE DONNED OXYGEN MASKS. THIS INCIDENT OCCURRED 15 MINS PRIOR TO SCHEDULED LNDG. NONE OF THE PAX RPTED ILL EFFECTS TO THE PARAMEDICS.