Regional Jet 700 ER/LR (CRJ700)
Flight Crew Commercial
Aircraft Equipment Problem Critical; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Flight Crew Diverted; General Declared Emergency
Aircraft; Weather
At 13;000 FT EICAS reported an ANTI-ICE DUCT MASTER WARNING and MASTER CAUTION. Checklist actions required securing the anti-ice system and exiting icing conditions. Once secured; the messages extinguished. Light rime was accreting and lower altitudes promptly provided by ARTCC did not provide an exit from the conditions. An emergency was then declared with ARTCC and the flight proceeded direct to a nearby airport without incident; remaining in icing conditions until landing. Due to current meteorological conditions and aircraft position and configuration; the chosen airport was the most suitable airport to land.
When on arrival while descending through 13;000 we entered into IMC and ICING conditions. A few minutes after turning our anti-ice equipment we received the 'ANTI ICE MASTER WARNING/CAUTION' and AURAL WARNING 'ANTI-ICE DUCT'. We turned off the anti-icing equipment and ran the QRH which instructed us to turn the system off and leave icing conditions IMMEDIATELY. We notified ATC that we needed to descend to 8;000 FT instead of 9;000 to exit icing conditions because our anti-ice equipment had failed; figuring it would be warm enough at that altitude. We experienced a temperature inversion and ATC was unable to give us lower when we asked for even lower to exit icing conditions. We decided to declare an emergency to get priority handling to a lower altitude and out of icing conditions. We informed ATC of our MASTER WARNING and lack of anti-icing equipment available. We landed safely and there was no additional action taken.
An ANTI-ICE MASTER WARNING msg in icing conditions led a regional jet crew to declare an emergency in order to exit icing conditions when ATC was unable to approve their requested altitude.