Narrative:

We departed from mdw on runway 31C at a takeoff weight of 85521 pounds. The conditions during departure were estimated ceiling 1700 ft overcast, 12 mi visibility, temperature 30 degrees, dewpoint 28 degrees, winds were 330 degrees at 15 KTS. We had turned on the engine heat during the start procedures. We turned on the airfoil ice protection during the climb, as we entered the clouds. I called for 'climb power, climb checklist' at 3000 ft AGL, and set both engines at 1.80 EPR (RAT/EPR gauge called for 1.93 climb power). About 4000 ft MSL, left engine EPR dropped to 1.6, and after approximately 10 seconds, the left engine fire warning sounded with all associated lights. I was the PF, so I retarded left throttle back to idle, and the fire warning went out immediately. We suspected bleed air leak at this time, and asked ATC to maintain heading to check into some indications. We were able to leveloff at 6000 ft, above the clouds, and turned off all ice protection, and closed the xfeed valves. When the airfoil ice protection cycle completed itself, I increased power on the left engine, and at 1.4 EPR, the fire warning signals reappeared. I retarded the power to idle, the signals went away. We declared an emergency, and requested an immediate return to mdw (due to signs of hot air leak) from ATC. We confirmed the WX in mdw, notified the flight attendants, then we told the passenger that we were returning to mdw as a precautionary measure due to signs of hot air leak from left engine. We completed the descent checklist, I briefed the ILS 31C at mdw, and we descended to 2500 ft MSL. At approximately 2600 ft MSL, below the icing, I chose to shut down the left engine to stop the hot air leak. We completed the in-flight engine shutdown checklist and we were cleared for the ILS runway 31C at mdw. I flew the approach, and we completed the before landing, and 1 engine before landing checklist. We had asked for the ground equipment to be standing by, just to confirm there was no smoke on the left side of the aircraft. We landed, turned off clear of the runway without incident, where the trucks came up to the rear of the airplane, and confirmed there was no smoke. All procedures and checklists were completed at the proper times with compliance with company policies. I would like to add that my entire crew handled itself in a professional and calm manner at all times.

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Original NASA ASRS Text

Title: INFLT FIRE WARNING. EMER DECLARED.

Narrative: WE DEPARTED FROM MDW ON RWY 31C AT A TKOF WT OF 85521 LBS. THE CONDITIONS DURING DEP WERE ESTIMATED CEILING 1700 FT OVCST, 12 MI VISIBILITY, TEMP 30 DEGS, DEWPOINT 28 DEGS, WINDS WERE 330 DEGS AT 15 KTS. WE HAD TURNED ON THE ENG HEAT DURING THE START PROCS. WE TURNED ON THE AIRFOIL ICE PROTECTION DURING THE CLB, AS WE ENTERED THE CLOUDS. I CALLED FOR 'CLB PWR, CLB CHKLIST' AT 3000 FT AGL, AND SET BOTH ENGS AT 1.80 EPR (RAT/EPR GAUGE CALLED FOR 1.93 CLB PWR). ABOUT 4000 FT MSL, L ENG EPR DROPPED TO 1.6, AND AFTER APPROX 10 SECONDS, THE L ENG FIRE WARNING SOUNDED WITH ALL ASSOCIATED LIGHTS. I WAS THE PF, SO I RETARDED L THROTTLE BACK TO IDLE, AND THE FIRE WARNING WENT OUT IMMEDIATELY. WE SUSPECTED BLEED AIR LEAK AT THIS TIME, AND ASKED ATC TO MAINTAIN HDG TO CHK INTO SOME INDICATIONS. WE WERE ABLE TO LEVELOFF AT 6000 FT, ABOVE THE CLOUDS, AND TURNED OFF ALL ICE PROTECTION, AND CLOSED THE XFEED VALVES. WHEN THE AIRFOIL ICE PROTECTION CYCLE COMPLETED ITSELF, I INCREASED PWR ON THE L ENG, AND AT 1.4 EPR, THE FIRE WARNING SIGNALS REAPPEARED. I RETARDED THE PWR TO IDLE, THE SIGNALS WENT AWAY. WE DECLARED AN EMER, AND REQUESTED AN IMMEDIATE RETURN TO MDW (DUE TO SIGNS OF HOT AIR LEAK) FROM ATC. WE CONFIRMED THE WX IN MDW, NOTIFIED THE FLT ATTENDANTS, THEN WE TOLD THE PAX THAT WE WERE RETURNING TO MDW AS A PRECAUTIONARY MEASURE DUE TO SIGNS OF HOT AIR LEAK FROM L ENG. WE COMPLETED THE DSCNT CHKLIST, I BRIEFED THE ILS 31C AT MDW, AND WE DSNDED TO 2500 FT MSL. AT APPROX 2600 FT MSL, BELOW THE ICING, I CHOSE TO SHUT DOWN THE L ENG TO STOP THE HOT AIR LEAK. WE COMPLETED THE INFLT ENG SHUTDOWN CHKLIST AND WE WERE CLRED FOR THE ILS RWY 31C AT MDW. I FLEW THE APCH, AND WE COMPLETED THE BEFORE LNDG, AND 1 ENG BEFORE LNDG CHKLIST. WE HAD ASKED FOR THE GND EQUIP TO BE STANDING BY, JUST TO CONFIRM THERE WAS NO SMOKE ON THE L SIDE OF THE ACFT. WE LANDED, TURNED OFF CLR OF THE RWY WITHOUT INCIDENT, WHERE THE TRUCKS CAME UP TO THE REAR OF THE AIRPLANE, AND CONFIRMED THERE WAS NO SMOKE. ALL PROCS AND CHKLISTS WERE COMPLETED AT THE PROPER TIMES WITH COMPLIANCE WITH COMPANY POLICIES. I WOULD LIKE TO ADD THAT MY ENTIRE CREW HANDLED ITSELF IN A PROFESSIONAL AND CALM MANNER AT ALL TIMES.

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.