EMB ERJ 145 ER/LR
Aircraft Equipment Problem Critical; Inflight Event / Encounter Weather / Turbulence
Flight Crew Took Evasive Action; General Declared Emergency
Aircraft; Weather
We were being vectored for approach and on the downwind we got a WING A-ICE FAIL master caution followed by an A-ICE INOP master warning. After adding more thrust the message initially went away. We had the thrust around 55% N1 but the master caution and warning came back and did not extinguish until we left icing conditions around 500 AGL. We assumed the anti ice system was malfunctioning so we declared an emergency to try to get out of the icing conditions as soon as possible. The main threat was the moderate icing. I read the memo pertaining to the anti ice messages associated with low power settings. I have seen these messages many times with low power settings. This is the only time I have ever seen these messages with a high power setting and they continued until we left icing.
EMB145 First Officer experiences wing anti ice failure during approach in icing conditions. An emergency is declared and the warning light extinguishes at 500 FT AGL on the approach.