Narrative:

Engine fire indication. This was the third leg with this aircraft. There was a previous write-up for a left fire loop B light illuminating which had been cleared by maintenance. The first leg, on climb out fire loop B light illuminated, we accomplished the appropriate procedure checking that fire loop a was operable. Continued to las. At las maintenance deferred fire loop B. The second leg, with outside temperature of 86 degrees (30 degrees C) takeoff left engine egt at 595 for 90 seconds. Upon landing sjc, maintenance inspected and conferred with maintenance controller technician all within engine limits. On the third leg, after takeoff, at approximately 4000 ft, fire loop a illuminated with a 'fire left engine' warning. Immediately reduced power, declared emergency, turned back to sjc, and briefed flight attendant. With the reduction of power the fire warning and lights extinguished. Requested arff/crash fire rescue equipment at sjc. Landed overweight at 137000 pounds, cleared runway 12L and parked. Requested an exterior inspection by the fire personnel and tower, then made a PA to have the flight attendant and passenger to remain in their seats. The left engine area had no indication of fire or smoke and I then taxied to the gate. There were no injuries or damage. Upon discussion with the mechanics I was shown a steel anti-ice duct that broke off the left engine shooting hot engine air into engine compartment. Supplemental information from acn 625842: we landed with both engines operating due to fire indications disappearing after throttle on affected engine was retarded.

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Original NASA ASRS Text

Title: MD80 FLT CREW RETURNED TO THEIR DEP ARPT WITH A #1 ENG FIRE WARNING.

Narrative: ENG FIRE INDICATION. THIS WAS THE THIRD LEG WITH THIS ACFT. THERE WAS A PREVIOUS WRITE-UP FOR A L FIRE LOOP B LIGHT ILLUMINATING WHICH HAD BEEN CLRED BY MAINT. THE FIRST LEG, ON CLBOUT FIRE LOOP B LIGHT ILLUMINATED, WE ACCOMPLISHED THE APPROPRIATE PROC CHKING THAT FIRE LOOP A WAS OPERABLE. CONTINUED TO LAS. AT LAS MAINT DEFERRED FIRE LOOP B. THE SECOND LEG, WITH OUTSIDE TEMP OF 86 DEGS (30 DEGS C) TKOF L ENG EGT AT 595 FOR 90 SECONDS. UPON LNDG SJC, MAINT INSPECTED AND CONFERRED WITH MAINT CTLR TECHNICIAN ALL WITHIN ENG LIMITS. ON THE THIRD LEG, AFTER TKOF, AT APPROX 4000 FT, FIRE LOOP A ILLUMINATED WITH A 'FIRE L ENG' WARNING. IMMEDIATELY REDUCED PWR, DECLARED EMER, TURNED BACK TO SJC, AND BRIEFED FLT ATTENDANT. WITH THE REDUCTION OF PWR THE FIRE WARNING AND LIGHTS EXTINGUISHED. REQUESTED ARFF/CFR AT SJC. LANDED OVERWEIGHT AT 137000 LBS, CLRED RWY 12L AND PARKED. REQUESTED AN EXTERIOR INSPECTION BY THE FIRE PERSONNEL AND TWR, THEN MADE A PA TO HAVE THE FLT ATTENDANT AND PAX TO REMAIN IN THEIR SEATS. THE L ENG AREA HAD NO INDICATION OF FIRE OR SMOKE AND I THEN TAXIED TO THE GATE. THERE WERE NO INJURIES OR DAMAGE. UPON DISCUSSION WITH THE MECHS I WAS SHOWN A STEEL ANTI-ICE DUCT THAT BROKE OFF THE L ENG SHOOTING HOT ENG AIR INTO ENG COMPARTMENT. SUPPLEMENTAL INFO FROM ACN 625842: WE LANDED WITH BOTH ENGS OPERATING DUE TO FIRE INDICATIONS DISAPPEARING AFTER THROTTLE ON AFFECTED ENG WAS RETARDED.

Data retrieved from NASA's ASRS site as of July 2007 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.