Narrative:

While climbing through approximately 15000 ft and just before we entered icing conditions, we turned on the engine anti-ice system. A little while later, the 'ice detected' light illuminated and we then turned on the outer wing and tail anti-ice system. A visual inspection of the wing revealed ice removal on the outer portion of the wing, but on the inner wing we had ice from just outside the outer engine pylons and inward as far as we could see just past the landing lights. We turned on the inner wing de-ice system. About 1 min later, the engine #1 air valve and engine #1 air fault, along with air low temperature caution lights illuminated. We cycled the #1 engine air off and on according to the QRH, which extinguished the engine #1 air valve light while the engine #1 air fault remained on. The ice on the inner portion of the wing remained. A short time later we exited icing conditions. During the flight in clear air we made repeated attempts to remove the inner wing ice with negative results. This, along with reports of icing conditions at the destination, msp, caused us to contact dispatch and maintenance control. Since no airborne fix was available, the decision was made to divert the flight to an airport with favorable WX within our range. Initially cid was considered as well as dsm. In coordination with chief pilot, dispatch, and my first officer and I, we decided to divert to dsm, which had essentially clear skies as well as united states customs on the field. As per company recommendation, we declared an emergency while en route to dsm. The passenger and flight attendants were informed during the entire process and kept up to date and assured of a continued safe flight. According to the QRH (wing not deiced), since a small amount of ice still adhered to the wing on approach to dsm, we added 15 KTS to the approach speed as well as adjusting approach to cross the threshold at vref +7 KTS to assure a safe landing. After the passenger were cleared by customs, they were rebooked on other flts to reach their destinations.

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Original NASA ASRS Text

Title: A BAE-146 FLT CREW HAS TROUBLE REMOVING ICE FROM THE WING RESULTING IN THE FLT CREW DECLARING AN EMER AND DIVERTING.

Narrative: WHILE CLBING THROUGH APPROX 15000 FT AND JUST BEFORE WE ENTERED ICING CONDITIONS, WE TURNED ON THE ENG ANTI-ICE SYS. A LITTLE WHILE LATER, THE 'ICE DETECTED' LIGHT ILLUMINATED AND WE THEN TURNED ON THE OUTER WING AND TAIL ANTI-ICE SYS. A VISUAL INSPECTION OF THE WING REVEALED ICE REMOVAL ON THE OUTER PORTION OF THE WING, BUT ON THE INNER WING WE HAD ICE FROM JUST OUTSIDE THE OUTER ENG PYLONS AND INWARD AS FAR AS WE COULD SEE JUST PAST THE LNDG LIGHTS. WE TURNED ON THE INNER WING DE-ICE SYS. ABOUT 1 MIN LATER, THE ENG #1 AIR VALVE AND ENG #1 AIR FAULT, ALONG WITH AIR LOW TEMP CAUTION LIGHTS ILLUMINATED. WE CYCLED THE #1 ENG AIR OFF AND ON ACCORDING TO THE QRH, WHICH EXTINGUISHED THE ENG #1 AIR VALVE LIGHT WHILE THE ENG #1 AIR FAULT REMAINED ON. THE ICE ON THE INNER PORTION OF THE WING REMAINED. A SHORT TIME LATER WE EXITED ICING CONDITIONS. DURING THE FLT IN CLR AIR WE MADE REPEATED ATTEMPTS TO REMOVE THE INNER WING ICE WITH NEGATIVE RESULTS. THIS, ALONG WITH RPTS OF ICING CONDITIONS AT THE DEST, MSP, CAUSED US TO CONTACT DISPATCH AND MAINT CTL. SINCE NO AIRBORNE FIX WAS AVAILABLE, THE DECISION WAS MADE TO DIVERT THE FLT TO AN ARPT WITH FAVORABLE WX WITHIN OUR RANGE. INITIALLY CID WAS CONSIDERED AS WELL AS DSM. IN COORD WITH CHIEF PLT, DISPATCH, AND MY FO AND I, WE DECIDED TO DIVERT TO DSM, WHICH HAD ESSENTIALLY CLR SKIES AS WELL AS UNITED STATES CUSTOMS ON THE FIELD. AS PER COMPANY RECOMMENDATION, WE DECLARED AN EMER WHILE ENRTE TO DSM. THE PAX AND FLT ATTENDANTS WERE INFORMED DURING THE ENTIRE PROCESS AND KEPT UP TO DATE AND ASSURED OF A CONTINUED SAFE FLT. ACCORDING TO THE QRH (WING NOT DEICED), SINCE A SMALL AMOUNT OF ICE STILL ADHERED TO THE WING ON APCH TO DSM, WE ADDED 15 KTS TO THE APCH SPD AS WELL AS ADJUSTING APCH TO CROSS THE THRESHOLD AT VREF +7 KTS TO ASSURE A SAFE LNDG. AFTER THE PAX WERE CLRED BY CUSTOMS, THEY WERE REBOOKED ON OTHER FLTS TO REACH THEIR DESTS.

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.