Narrative:

At cruise FL390; 80 mi north of ZZZ; aft cargo fire warning light illuminated; with no other indications of fire; ie; master warning; master fire light; etc. Accomplished qrc aft cargo fire. Notified dispatch and maintenance of situation. Declared an emergency with ATC. Diverted to ZZZ. Advised flight attendants. Requested fire and rescue equipment at ZZZ. After landing; cleared runway and outside of aircraft was inspected by company personnel and fire rescue personnel. There was no indication of fire or smoke. Aircraft towed to gate. Aircraft was deemed safe and airworthy by local maintenance. Captain and first officer ferried aircraft to ZZZ1. Debriefed with safety committee as well as FAA. In sum; light appeared to be indication only; and our flight attendants and the aircraft fire and rescue personnel at ZZZ all acted in a very professional manner.

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Original NASA ASRS Text

Title: B757 FLT CREW REPORTS CARGO FIRE WARNING WITH NO OTHER INDICATIONS AND AFTER COMPLYING WITH QRH DIVERTS TO NEAREST SUITABLE ARPT.

Narrative: AT CRUISE FL390; 80 MI N OF ZZZ; AFT CARGO FIRE WARNING LIGHT ILLUMINATED; WITH NO OTHER INDICATIONS OF FIRE; IE; MASTER WARNING; MASTER FIRE LIGHT; ETC. ACCOMPLISHED QRC AFT CARGO FIRE. NOTIFIED DISPATCH AND MAINT OF SITUATION. DECLARED AN EMER WITH ATC. DIVERTED TO ZZZ. ADVISED FLT ATTENDANTS. REQUESTED FIRE AND RESCUE EQUIP AT ZZZ. AFTER LNDG; CLRED RWY AND OUTSIDE OF ACFT WAS INSPECTED BY COMPANY PERSONNEL AND FIRE RESCUE PERSONNEL. THERE WAS NO INDICATION OF FIRE OR SMOKE. ACFT TOWED TO GATE. ACFT WAS DEEMED SAFE AND AIRWORTHY BY LCL MAINT. CAPT AND FO FERRIED ACFT TO ZZZ1. DEBRIEFED WITH SAFETY COMMITTEE AS WELL AS FAA. IN SUM; LIGHT APPEARED TO BE INDICATION ONLY; AND OUR FLT ATTENDANTS AND THE ACFT FIRE AND RESCUE PERSONNEL AT ZZZ ALL ACTED IN A VERY PROFESSIONAL MANNER.

Data retrieved from NASA's ASRS site as of May 2009 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.