Narrative:

About 20 mins into the flight we got a 'left engine overheat LP1' status message. A few mins later it changed to a 'left engine fire LP1' status message. I completed a fire warning test and it was good. Passing FL330 in the climb; we got a left engine fire warning. All engine instruments appeared normal. I leveled off at FL330 and performed the recall items for engine fire. When I pulled the left throttle to idle the fire warning ceased. With the left engine at idle; I declared an emergency and turned back. I briefed flight attendant on the situation and asked her to look at the left engine for signs of a fire. There were none. In the descent; I pushed the left throttle up slightly and the fire warning immediately started. I returned the left throttle to idle; the fire warning quit; and first officer completed the remainder of the engine fire checklist. After briefing the passenger and flight control; I flew a single engine approach to ZZZ. After exiting runway at the end; the fire marshal checked us over and saw no signs of a fire. We continued to the gate. According to maintenance coordinator; they found a cracked elbow coming off the high pressure turbine recoup duct.

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Original NASA ASRS Text

Title: B767 ENG FIRE WARNING ACTIVATED DURING CLIMB. FLT CREW DECLARED AN EMER AND THE FLT RETURNED TO DEP ARPT.

Narrative: ABOUT 20 MINS INTO THE FLT WE GOT A 'L ENG OVERHEAT LP1' STATUS MESSAGE. A FEW MINS LATER IT CHANGED TO A 'L ENG FIRE LP1' STATUS MESSAGE. I COMPLETED A FIRE WARNING TEST AND IT WAS GOOD. PASSING FL330 IN THE CLB; WE GOT A L ENG FIRE WARNING. ALL ENG INSTS APPEARED NORMAL. I LEVELED OFF AT FL330 AND PERFORMED THE RECALL ITEMS FOR ENG FIRE. WHEN I PULLED THE L THROTTLE TO IDLE THE FIRE WARNING CEASED. WITH THE L ENG AT IDLE; I DECLARED AN EMER AND TURNED BACK. I BRIEFED FLT ATTENDANT ON THE SITUATION AND ASKED HER TO LOOK AT THE L ENG FOR SIGNS OF A FIRE. THERE WERE NONE. IN THE DSCNT; I PUSHED THE L THROTTLE UP SLIGHTLY AND THE FIRE WARNING IMMEDIATELY STARTED. I RETURNED THE L THROTTLE TO IDLE; THE FIRE WARNING QUIT; AND FO COMPLETED THE REMAINDER OF THE ENG FIRE CHKLIST. AFTER BRIEFING THE PAX AND FLT CTL; I FLEW A SINGLE ENG APCH TO ZZZ. AFTER EXITING RWY AT THE END; THE FIRE MARSHAL CHKED US OVER AND SAW NO SIGNS OF A FIRE. WE CONTINUED TO THE GATE. ACCORDING TO MAINT COORDINATOR; THEY FOUND A CRACKED ELBOW COMING OFF THE HIGH PRESSURE TURBINE RECOUP DUCT.

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.