Narrative:

Between FL070-080; the #2 bleed low temp light illuminated. At FL090 the flight was out of ice and the light went out. The flight was climbing and called me on company radio and asked to be patched to maintenance. After telling maintenance of the problem; I was conferring with the company weather service for icing conditions and looking for the best plan of action for the flight. Captain was above the clouds and out of ice and climbed to FL250 to conserve fuel with 5.4 fob. After reviewing weather; decided returning was not a good idea; as there was snow in and around the area and the captain stated after he landed; he would have been in icing conditions from FL080 - sfc if he had gone back. The destination was OVC075 with cool surface temps. Looking at surrounding weather; I found ZZZ to have clear weather on the hourly observation and OVC100 for ZZZ forecast. Captain and I agreed that ZZZ would be the best plan and safest to get the flight on the ground. At this time flight was about 50mi southwest of ZZZ1 and ran numbers with 5.0 fob at FL250 from ZZZ1-ZZZ (approx 400 lbs). Sent fuel numbers and amendment to crew and he had ZZZ weather on his release ; as ZZZ was his alternate on the original release; however; I thought I sent current ZZZ weather to captain; but realized it did not go through. Flight landed safely and without incident in ZZZ. Captain advised me before he descended; he verified with the local tower at ZZZ that the weather was clear and advised ATC he was declaring an emergency at FL250 and descended through clouds at a higher rate of speed than normal and upon reaching 9500ft was below the cloud deck and reported only picking up very little ice on windshield. Capt advised ATC he had ZZZ airport in sight and undeclared the emergency and had no further icing issues until landing.

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Original NASA ASRS Text

Title: Dispatcher reports the circumstances and decisions surrounding a EMB145 diversion due to anti-ice system failure.

Narrative: Between FL070-080; the #2 bleed low temp light illuminated. At FL090 the flight was out of ice and the light went out. The flight was climbing and called me on company radio and asked to be patched to Maintenance. After telling Maintenance of the problem; I was conferring with the company weather service for icing conditions and looking for the best plan of action for the flight. Captain was above the clouds and out of ice and climbed to FL250 to conserve fuel with 5.4 FOB. After reviewing weather; decided returning was not a good idea; as there was snow in and around the area and the Captain stated after he landed; he would have been in icing conditions from FL080 - SFC if he had gone back. The destination was OVC075 with cool surface temps. Looking at surrounding weather; I found ZZZ to have clear weather on the hourly observation and OVC100 for ZZZ forecast. Captain and I agreed that ZZZ would be the best plan and safest to get the flight on the ground. At this time flight was about 50mi SW of ZZZ1 and ran numbers with 5.0 FOB at FL250 from ZZZ1-ZZZ (approx 400 lbs). Sent fuel numbers and amendment to Crew and he had ZZZ weather on his release ; as ZZZ was his alternate on the original release; however; I thought I sent current ZZZ weather to Captain; but realized it did not go through. Flight landed safely and without incident in ZZZ. Captain advised me before he descended; he verified with the local Tower at ZZZ that the weather was clear and advised ATC he was declaring an emergency at FL250 and descended through clouds at a higher rate of speed than normal and upon reaching 9500ft was below the cloud deck and reported only picking up very little ice on windshield. Capt advised ATC he had ZZZ airport in sight and undeclared the emergency and had no further icing issues until landing.

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.