AN MD11 ON TKOF AT 200 FT DECLARED AN EMER; DUMPED FUEL; FIRED BOTH FIRE EXTINGUISHER BOTTLES AND DIVERTED DUE TO A FIRE WARNING IN #1 ENG CAUSED BY A DEFECTIVE ENG FIRE SENSOR LOOP.

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OUT AT XA00 JUN/XX/98; TKOF ABORTED AT 70 KTS AURAL FIRE WARNING AND BELL ENG FIRE #1. RETURNED TO RAMP. MAINT HAD US PARK ON THE RAMP. ENTERED THROUGH E&E; CHANGED 2 BOXES. AURAL AND FIRE SECOND TKOF. FULL ENG FIRE WARNING AT APPROX 200 FT. PROCEEDED WITH FULL ENG FIRE CHKLIST. FUEL DUMP COMMENCED AFTER ENG FIRE WARNING AND SHUTDOWN. BOTH BOTTLES WERE FIRED AS ENG DETECTOR FAIL WARNING ALSO ILLUMINATED; DECLARED AN EMER; DUMPED APPROX 150000 LBS OF FUEL DOWN TO 440000; LANDED AT 438000 LBS; SINK 100- 200 FPM. I HAD FIRE TRUCK MEET THE ACFT AT RWY TURN-OFF TO VISUALLY CHK ENG #1. NO EVIDENCE OF FIRE. CONTINUED TO THE RAMP. TEST BRIEFINGS AND PA'S TO THE PAX WERE MADE TO ENSURE UNDERSTANDING OF THE RELATIVE NORMALITY OF THE SIT. SUSPECT FALSE WARNING; FAULTY SYS OR BROKEN AIR DUCT. ACFT NUMBER XYZ. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS OTS FOR SEVERAL DAYS AND MAINT RPTED THE CAUSE WAS A FAILED ENG FIRE WARNING LOOP. THE RPTR SAID ONE FIRE LOOP WAS DEFERRED AS INOP AND HAD BEEN CARRIED FOR SEVERAL DAYS PRIOR TO THIS EVENT. THE RPTR SAID MAINT HAD TO REPLACE BOTH FIRE WARNING LOOPS.