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.