Narrative:

Upon takeoff, climbing through 4000 ft MSL we received reports of moderate icing. Shortly after, we experienced airframe ice. This was verified by ice accumulating on the windshield and wipers. The icing condition message was displayed on the EICAS, indicating that we were presently in icing conditions. The EICAS then displayed a message that the stabilizer anti-ice system had failed. We verified the indication that the stabilizer ice valve did not open as it should to deliver bleed air to the horizontal stabilizer. We, as a crew, followed the stabilizer anti- ice fail checklist per the aircraft operations manual. Due to our concern for ice accumulation on the unprotected stabilizer, we declared an emergency stating that we had lost ice protection on our horizontal stabilizer, were accumulating ice, and needed immediate vectors back to ord with equipment standing by. Callback conversation with reporter revealed the following information: the reporter stated the EMB145 has a recurring problem which the manufacturer is making a great effort to solve, that being the anti-ice pneumatic valve reliability. The reporter said the stabilizer anti-ice warning came on in known icing conditions, followed by the red master caution. The reporter said the EMB145 aircraft is fairly new, and is equipped with a fully automatic anti- icing system that self-tests prior to takeoff. The reporter said 2 ice probes detect icing conditions and control the valves that direct pneumatic air to the wing and stabilizer leading edges. The reporter stated the system self test was ok prior to takeoff. The reporter was not advised by maintenance of the failed component, but believes it was a failed stabilizer pneumatic valve.

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Original NASA ASRS Text

Title: AN EMBRAER 145 IN CLB AT 5000 FT IN ICING CONDITIONS DECLARED AN EMER AND DIVERTED DUE TO THE STABILIZER ANTI- ICE SYS FAILURE WARNING.

Narrative: UPON TKOF, CLBING THROUGH 4000 FT MSL WE RECEIVED RPTS OF MODERATE ICING. SHORTLY AFTER, WE EXPERIENCED AIRFRAME ICE. THIS WAS VERIFIED BY ICE ACCUMULATING ON THE WINDSHIELD AND WIPERS. THE ICING CONDITION MESSAGE WAS DISPLAYED ON THE EICAS, INDICATING THAT WE WERE PRESENTLY IN ICING CONDITIONS. THE EICAS THEN DISPLAYED A MESSAGE THAT THE STABILIZER ANTI-ICE SYS HAD FAILED. WE VERIFIED THE INDICATION THAT THE STABILIZER ICE VALVE DID NOT OPEN AS IT SHOULD TO DELIVER BLEED AIR TO THE HORIZ STABILIZER. WE, AS A CREW, FOLLOWED THE STABILIZER ANTI- ICE FAIL CHKLIST PER THE ACFT OPS MANUAL. DUE TO OUR CONCERN FOR ICE ACCUMULATION ON THE UNPROTECTED STABILIZER, WE DECLARED AN EMER STATING THAT WE HAD LOST ICE PROTECTION ON OUR HORIZ STABILIZER, WERE ACCUMULATING ICE, AND NEEDED IMMEDIATE VECTORS BACK TO ORD WITH EQUIP STANDING BY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE EMB145 HAS A RECURRING PROB WHICH THE MANUFACTURER IS MAKING A GREAT EFFORT TO SOLVE, THAT BEING THE ANTI-ICE PNEUMATIC VALVE RELIABILITY. THE RPTR SAID THE STABILIZER ANTI-ICE WARNING CAME ON IN KNOWN ICING CONDITIONS, FOLLOWED BY THE RED MASTER CAUTION. THE RPTR SAID THE EMB145 ACFT IS FAIRLY NEW, AND IS EQUIPPED WITH A FULLY AUTOMATIC ANTI- ICING SYS THAT SELF-TESTS PRIOR TO TKOF. THE RPTR SAID 2 ICE PROBES DETECT ICING CONDITIONS AND CTL THE VALVES THAT DIRECT PNEUMATIC AIR TO THE WING AND STABILIZER LEADING EDGES. THE RPTR STATED THE SYS SELF TEST WAS OK PRIOR TO TKOF. THE RPTR WAS NOT ADVISED BY MAINT OF THE FAILED COMPONENT, BUT BELIEVES IT WAS A FAILED STABILIZER PNEUMATIC VALVE.

Data retrieved from NASA's ASRS site as of July 2007 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.