Narrative:

During our climb out from our departure station we received a warning that there was an overheated anti-ice duct. Per the QRH procedure we shut down the bleed air supply; which left us with no anti-ice capabilities. Our route of flight would certainly bring us into icing conditions. A return to our departure station would also technically result in flight through icing conditions as the temperature was less than 10 deg C with light rain (surface temp was 3 deg C). We were not in icing conditions at 10000 feet (+12 deg C). A return to our departure station seemed to be our best option; as we had not picked up any ice during the departure. We contacted dispatch to inform them of our possible return to our departure station and also asked if there were other cities nearby that would have VMC conditions. Several options were presented; but all were IMC; and we had serious doubts about our chances of staying clear of icing conditions enroute to these locations. We did not have the luxury of time; as the temp was near freezing in our departure station and active icing could begin to be a factor shortly. As the conditions in our departure station were known to us to be presently free of active icing; I elected to return to our departure station. Initially I did not declare an emergency; however after further consideration of the potential for undetected ice accumulations on the engine inlet cowls I changed my mind and declared an emergency with approach control. The landing was uneventful.

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Original NASA ASRS Text

Title: An Air Carrier flight crew experiences an anti-ice duct overheat during climb out and elects to return to departure airport since icing conditions cannot be avoided enroute.

Narrative: During our climb out from our departure station we received a warning that there was an overheated anti-ice duct. Per the QRH procedure we shut down the bleed air supply; which left us with no anti-ice capabilities. Our route of flight would certainly bring us into icing conditions. A return to our departure station would also technically result in flight through icing conditions as the temperature was less than 10 deg C with light rain (surface temp was 3 deg C). We were not in icing conditions at 10000 feet (+12 deg C). A return to our departure station seemed to be our best option; as we had not picked up any ice during the departure. We contacted dispatch to inform them of our possible return to our departure station and also asked if there were other cities nearby that would have VMC conditions. Several options were presented; but all were IMC; and we had serious doubts about our chances of staying clear of icing conditions enroute to these locations. We did not have the luxury of time; as the temp was near freezing in our departure station and active icing could begin to be a factor shortly. As the conditions in our departure station were known to us to be presently free of active icing; I elected to return to our departure station. Initially I did not declare an emergency; however after further consideration of the potential for undetected ice accumulations on the engine inlet cowls I changed my mind and declared an emergency with Approach Control. The landing was uneventful.

Data retrieved from NASA's ASRS site as of April 2012 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.