Narrative:

We were deiced with type 1 fluid to remove morning frost. I asked the first officer to turn engine bleed air valves to off position for a few mins after engine start, to prevent cabin smoke in case of glycol ingestion. After engines were run for a few mins, the bleed valves were returned to the normal 'on' position. We taxied for about 5 mins and conducted a routine engine test at the end of runway 11. We departed bmi without any problems. About 10-15 mins after takeoff, we observed an electric smoke caption along with master warning and repetitive chime. In the ATR, an electric smoke caption can mean either a fire in the avionics compartment or smoke in the environmental control system, depending on the order that smoke is sensed by the crew in relation to the activation of the caption. Since neither my first officer, both flight attendants, nor myself smelled or observed any smoke prior to the caption activation, we determined the warning to be an avionics fire rather than smoke from our air conditioning system. Therefore, I called for the electric smoke checklist rather than the air conditioning smoke checklist. After shutting down the listed system in the checklist, the smoke detector continued to send an electric smoke warning. We notified peoria departure of our problem indication, but no apparent smoke, and our need for a precautionary return to bmi. A turn and descent was issued and executed immediately. Since the alert was still active, the first officer also ran through the air conditioning smoke checklist. Just prior to landing, the fire system stopped sensing smoke and the alert disappeared. We landed in bmi without incident and, since none of us smelled or saw any smoke, we dismissed the fire trucks and deplaned the passenger in a normal fashion at our gate. I wrote up the discrepancy in the aircraft logbook and called company maintenance and dispatch. A company mechanic was dispatched on the next flight to bmi. After running both engines for about 10 mins without any warning generated and no fire damage observed, he determined that the alert must have been triggered by excess glycol in the engine. He signed off the discrepancy corrective action column and we departed bmi without incident.

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Original NASA ASRS Text

Title: AT72 CREW HAD AN 'ELECTRIC SMOKE' WARNING AFTER BEING DEICED WITH TYPE 1 GLYCOL DEICING FLUID.

Narrative: WE WERE DEICED WITH TYPE 1 FLUID TO REMOVE MORNING FROST. I ASKED THE FO TO TURN ENG BLEED AIR VALVES TO OFF POS FOR A FEW MINS AFTER ENG START, TO PREVENT CABIN SMOKE IN CASE OF GLYCOL INGESTION. AFTER ENGS WERE RUN FOR A FEW MINS, THE BLEED VALVES WERE RETURNED TO THE NORMAL 'ON' POS. WE TAXIED FOR ABOUT 5 MINS AND CONDUCTED A ROUTINE ENG TEST AT THE END OF RWY 11. WE DEPARTED BMI WITHOUT ANY PROBS. ABOUT 10-15 MINS AFTER TKOF, WE OBSERVED AN ELECTRIC SMOKE CAPTION ALONG WITH MASTER WARNING AND REPETITIVE CHIME. IN THE ATR, AN ELECTRIC SMOKE CAPTION CAN MEAN EITHER A FIRE IN THE AVIONICS COMPARTMENT OR SMOKE IN THE ENVIRONMENTAL CTL SYS, DEPENDING ON THE ORDER THAT SMOKE IS SENSED BY THE CREW IN RELATION TO THE ACTIVATION OF THE CAPTION. SINCE NEITHER MY FO, BOTH FLT ATTENDANTS, NOR MYSELF SMELLED OR OBSERVED ANY SMOKE PRIOR TO THE CAPTION ACTIVATION, WE DETERMINED THE WARNING TO BE AN AVIONICS FIRE RATHER THAN SMOKE FROM OUR AIR CONDITIONING SYS. THEREFORE, I CALLED FOR THE ELECTRIC SMOKE CHKLIST RATHER THAN THE AIR CONDITIONING SMOKE CHKLIST. AFTER SHUTTING DOWN THE LISTED SYS IN THE CHKLIST, THE SMOKE DETECTOR CONTINUED TO SEND AN ELECTRIC SMOKE WARNING. WE NOTIFIED PEORIA DEP OF OUR PROB INDICATION, BUT NO APPARENT SMOKE, AND OUR NEED FOR A PRECAUTIONARY RETURN TO BMI. A TURN AND DSCNT WAS ISSUED AND EXECUTED IMMEDIATELY. SINCE THE ALERT WAS STILL ACTIVE, THE FO ALSO RAN THROUGH THE AIR CONDITIONING SMOKE CHKLIST. JUST PRIOR TO LNDG, THE FIRE SYS STOPPED SENSING SMOKE AND THE ALERT DISAPPEARED. WE LANDED IN BMI WITHOUT INCIDENT AND, SINCE NONE OF US SMELLED OR SAW ANY SMOKE, WE DISMISSED THE FIRE TRUCKS AND DEPLANED THE PAX IN A NORMAL FASHION AT OUR GATE. I WROTE UP THE DISCREPANCY IN THE ACFT LOGBOOK AND CALLED COMPANY MAINT AND DISPATCH. A COMPANY MECH WAS DISPATCHED ON THE NEXT FLT TO BMI. AFTER RUNNING BOTH ENGS FOR ABOUT 10 MINS WITHOUT ANY WARNING GENERATED AND NO FIRE DAMAGE OBSERVED, HE DETERMINED THAT THE ALERT MUST HAVE BEEN TRIGGERED BY EXCESS GLYCOL IN THE ENG. HE SIGNED OFF THE DISCREPANCY CORRECTIVE ACTION COLUMN AND WE DEPARTED BMI WITHOUT INCIDENT.

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.