Narrative:

[We] experienced an 'anti-ice duct' emergency in flight. The emergency occurred in icing conditions during the initial arrival phase into [destination]. At the time the event occurred the aircraft was in known icing conditions and the ice detecting system indicated ice. Less than 30 seconds after turning on both the cowl and wing anti-ice switches; the anti-ice duct master warning was indicated by the EICAS system. The aircraft flight controls were transferred from the first officer to the captain. The captain [notified ATC] and began to immediately climb out of icing conditions while advising ATC of the situation. At the time the aircraft altitude was 10;000 feet MSL. ATC authorized a climb to 14;000 feet. The captain requested 15;000 to remain above the cloud deck. At the time the cloud bases were reported to be 2;200 above field elevation with an outside air temperature less than freezing. The first officer completed the QRH procedure. The captain elected to return to [departure airport] as icing conditions were not known to be [there]. The first officer agreed with the captain's decision to return. After completing the QRH procedures; the flight attendants were advised of the situation; the company was advised of the situation; the passengers were made aware of the reason why the flight was returning. For safety reasons; emergency equipment was requested to be ready. This captain requested a straight in approach and the request was granted by ATC. The aircraft was safely landed without further incident and was able to return to the gate under its own power. The passengers were briefed on the event by the captain and subsequently de-planed. This was the second time within a 2 week period that this captain experienced this emergency with this same aircraft.

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Original NASA ASRS Text

Title: CRJ-700 Captain reported returning to departure airport after experiencing an 'ANTI ICE DUCT' Master Warning.

Narrative: [We] experienced an 'ANTI-ICE DUCT' emergency in flight. The emergency occurred in icing conditions during the initial arrival phase into [destination]. At the time the event occurred the aircraft was in known icing conditions and the ice detecting system indicated ICE. Less than 30 seconds after turning on both the cowl and wing anti-ice switches; the ANTI-ICE DUCT Master Warning was indicated by the EICAS System. The aircraft flight controls were transferred from the First Officer to the Captain. The Captain [notified ATC] and began to immediately climb out of icing conditions while advising ATC of the situation. At the time the aircraft altitude was 10;000 feet MSL. ATC authorized a climb to 14;000 feet. The Captain requested 15;000 to remain above the cloud deck. At the time the cloud bases were reported to be 2;200 above field elevation with an outside air temperature less than freezing. The First Officer completed the QRH procedure. The Captain elected to return to [departure airport] as icing conditions were not known to be [there]. The First Officer agreed with the Captain's decision to return. After completing the QRH procedures; the flight attendants were advised of the situation; the company was advised of the situation; the passengers were made aware of the reason why the flight was returning. For safety reasons; emergency equipment was requested to be ready. This Captain requested a straight in approach and the request was granted by ATC. The aircraft was safely landed without further incident and was able to return to the gate under its own power. The passengers were briefed on the event by the Captain and subsequently de-planed. This was the second time within a 2 week period that this Captain experienced this emergency with this same aircraft.

Data retrieved from NASA's ASRS site 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.