An emb-145 flight crew declared an emergency and descended out of icing conditions when both captain...

Narrative:

While in cruise at FL360 we received an 'IAS' comparitor notice on the pfd. We were in icing conditions and suspected an icing problem. I selected the de-icing system to 'on' manually. We started a descent to get to a warmer altitude and to get out of icing conditions. Both captain and first officer pfd's appeared to be failing as indicated airspeed was decreasing on the display. An emergency was declared and while trying to maintain airspeed by following the indicated airspeed on the pfd we possibly oversped the plane on descent. When cross referencing the standby airspeed indicator it read 340 to 350. Leaving icing conditions we got airspeed indications back on both pfd's and we continued to our destination without further problems.maintenance should check this airplane to see why the pitot static system wasn't heating and why the anti ice/de-ice system didn't automatically come on. Suspect some kind of failure even though we didn't get an EICAS warning of a system failure.

Original NASA ASRS Text

Title: An EMB-145 flight crew declared an emergency and descended out of icing conditions when both Captain and First Officers' airspeed indicators showed erroneous information.

Narrative: While in cruise at FL360 we received an 'IAS' COMPARITOR notice on the PFD. We were in icing conditions and suspected an icing problem. I selected the de-icing system to 'on' manually. We started a descent to get to a warmer altitude and to get out of icing conditions. Both Captain and First Officer PFD's appeared to be failing as indicated airspeed was decreasing on the display. An emergency was declared and while trying to maintain airspeed by following the indicated airspeed on the PFD we possibly oversped the plane on descent. When cross referencing the standby airspeed indicator it read 340 to 350. Leaving icing conditions we got airspeed indications back on both PFD's and we continued to our destination without further problems.Maintenance should check this airplane to see why the pitot static system wasn't heating and why the Anti Ice/De-ice system didn't automatically come on. Suspect some kind of failure even though we didn't get an EICAS warning of a system failure.

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.

Attributes
ACN	887966
Time
Date	201005
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	EMB ERJ 145 ER&LR
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Pitot/Static Ice System
Person 1
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Flying First Officer
Qualification	Flight Crew Commercial
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Speed All Types Inflight Event / Encounter Weather / Turbulence

An emb-145 flight crew declared an emergency and descended out of icing conditions when both captain and first officers' airspeed indicators showed erroneous information.