Narrative:

It was late at night after a ZZZ1 turn. We had 1 more short leg and we were going to our layover hotel when we landed. We completed all of the cockpit checks and duties. Our engine starts and taxi were normal. While taxiing to runway we saw that the windsock was limp. There was no other traffic except an MD80 behind us for takeoff. We were cleared for takeoff and everything appeared normal until around 500 ft. We had a fire detector loop annunciator light and a master caution light. Within seconds the fire left engine warning light and the voice and bell were ringing in our ears. I silenced the bell and asked captain if he wanted me to pull the fire handle? We had noted all of the engine parameters were normal. He said no. We continued our climb and he told me to tell the tower that we wanted to declare an emergency and return to land. The tower controller told us we could land on xxr. Captain said that would be great. So he leveled and brought the power back. Almost immediately the fire light went out. We did a horseshoe (180 degree) pattern and we stayed very close to the airport. We decided to land quickly instead of pulling out the QRH. All engine indications were still normal. He slowed the airplane so we could put down the gear and flaps. We were looking for xxr and the ILS frequency that the controller gave us wasn't working. So we asked for a vector. He turned up the lights on the runway and we got a visual. Captain added power and the fire left engine light illuminated again and this time he instructed me to pull the fire handle. The light extinguished almost immediately. We asked the tower if they saw any fire. He didn't see any indication of a fire. We landed single engine in the first 1/3 of the runway and the touchdown was smooth. It seemed like a routine landing. Once we stopped on the runway; captain talked to the passenger and flight attendants and I talked to the tower and then to the firemen. They used their equipment to determine that we didn't have a fire and we were safe to taxi to the gate. They followed us to the gate and the passenger deplaned via the jetbridge. I did a postflt inspection of the airplane. I wanted to see for myself that there wasn't a fire. The engine from the bottom of the airplane appeared normal. I talked to the mechanic and he said that the left engine cowl was very warm to the touch when he arrived. He was thinking that there was probably a left engine anti-ice line with a crack up on top of the engine.

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Original NASA ASRS Text

Title: IMMEDIATELY AFTER TKOF; AN MD80'S FIRE DET LOOP; MASTER CAUTION; AND ENGINE FIRE WARNING ILLUMINATED. AN EMER WAS DECLARED WITH A RETURN TO LAND.

Narrative: IT WAS LATE AT NIGHT AFTER A ZZZ1 TURN. WE HAD 1 MORE SHORT LEG AND WE WERE GOING TO OUR LAYOVER HOTEL WHEN WE LANDED. WE COMPLETED ALL OF THE COCKPIT CHKS AND DUTIES. OUR ENG STARTS AND TAXI WERE NORMAL. WHILE TAXIING TO RWY WE SAW THAT THE WINDSOCK WAS LIMP. THERE WAS NO OTHER TFC EXCEPT AN MD80 BEHIND US FOR TKOF. WE WERE CLRED FOR TKOF AND EVERYTHING APPEARED NORMAL UNTIL AROUND 500 FT. WE HAD A FIRE DETECTOR LOOP ANNUNCIATOR LIGHT AND A MASTER CAUTION LIGHT. WITHIN SECONDS THE FIRE L ENG WARNING LIGHT AND THE VOICE AND BELL WERE RINGING IN OUR EARS. I SILENCED THE BELL AND ASKED CAPT IF HE WANTED ME TO PULL THE FIRE HANDLE? WE HAD NOTED ALL OF THE ENG PARAMETERS WERE NORMAL. HE SAID NO. WE CONTINUED OUR CLB AND HE TOLD ME TO TELL THE TWR THAT WE WANTED TO DECLARE AN EMER AND RETURN TO LAND. THE TWR CTLR TOLD US WE COULD LAND ON XXR. CAPT SAID THAT WOULD BE GREAT. SO HE LEVELED AND BROUGHT THE PWR BACK. ALMOST IMMEDIATELY THE FIRE LIGHT WENT OUT. WE DID A HORSESHOE (180 DEG) PATTERN AND WE STAYED VERY CLOSE TO THE ARPT. WE DECIDED TO LAND QUICKLY INSTEAD OF PULLING OUT THE QRH. ALL ENG INDICATIONS WERE STILL NORMAL. HE SLOWED THE AIRPLANE SO WE COULD PUT DOWN THE GEAR AND FLAPS. WE WERE LOOKING FOR XXR AND THE ILS FREQ THAT THE CTLR GAVE US WASN'T WORKING. SO WE ASKED FOR A VECTOR. HE TURNED UP THE LIGHTS ON THE RWY AND WE GOT A VISUAL. CAPT ADDED PWR AND THE FIRE L ENG LIGHT ILLUMINATED AGAIN AND THIS TIME HE INSTRUCTED ME TO PULL THE FIRE HANDLE. THE LIGHT EXTINGUISHED ALMOST IMMEDIATELY. WE ASKED THE TWR IF THEY SAW ANY FIRE. HE DIDN'T SEE ANY INDICATION OF A FIRE. WE LANDED SINGLE ENG IN THE FIRST 1/3 OF THE RWY AND THE TOUCHDOWN WAS SMOOTH. IT SEEMED LIKE A ROUTINE LNDG. ONCE WE STOPPED ON THE RWY; CAPT TALKED TO THE PAX AND FLT ATTENDANTS AND I TALKED TO THE TWR AND THEN TO THE FIREMEN. THEY USED THEIR EQUIP TO DETERMINE THAT WE DIDN'T HAVE A FIRE AND WE WERE SAFE TO TAXI TO THE GATE. THEY FOLLOWED US TO THE GATE AND THE PAX DEPLANED VIA THE JETBRIDGE. I DID A POSTFLT INSPECTION OF THE AIRPLANE. I WANTED TO SEE FOR MYSELF THAT THERE WASN'T A FIRE. THE ENG FROM THE BOTTOM OF THE AIRPLANE APPEARED NORMAL. I TALKED TO THE MECH AND HE SAID THAT THE L ENG COWL WAS VERY WARM TO THE TOUCH WHEN HE ARRIVED. HE WAS THINKING THAT THERE WAS PROBABLY A L ENG ANTI-ICE LINE WITH A CRACK UP ON TOP OF THE ENG.

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.