Narrative:

All items on checklist were called and met. Temperature at the time of takeoff was approximately 18 degrees C. Close to approximately 10000 ft, we lost airspeed indications on both sides -- captain's and first officer's. Altimeter was fluctuating between 5000-11000 ft. We had only roll information and no pitch information. Standby attitude indicator was working. However, there was no altitude and airspeed indications on standby instruments. We advised pit departure of the situation. We asked for vectors to pit and descent to lowest possible altitude. At or about 3000 ft, all instruments came back. We were vectored for runway 28R approach and landed visually. Aircraft was thoroughly checked and nothing was found wrong. Aircraft is being checked by company and fairchild technicians. Captain reports that after investigation by the aircraft manufacturer, they concluded the probe heat was not on. The captain refutes this as there was no EICAS probe heat warning. Also, there was no blue ice detection warning light illuminated. The captain stated that the problem occurred only when in moderate to heavy rain. The outside air temperature was never at freezing or below. As soon as the aircraft descended and flew out of the rain the problems stopped. In conversation with the air carrier chief pilot, he indicated that this was a known problem with the turboprop version of the aircraft. The captain also knows of other occurrences with this model aircraft.

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Original NASA ASRS Text

Title: D328 CREW HAD ACFT INSTRUMENTATION FAIL IN IMC.

Narrative: ALL ITEMS ON CHKLIST WERE CALLED AND MET. TEMP AT THE TIME OF TKOF WAS APPROX 18 DEGS C. CLOSE TO APPROX 10000 FT, WE LOST AIRSPD INDICATIONS ON BOTH SIDES -- CAPT'S AND FO'S. ALTIMETER WAS FLUCTUATING BTWN 5000-11000 FT. WE HAD ONLY ROLL INFO AND NO PITCH INFO. STANDBY ATTITUDE INDICATOR WAS WORKING. HOWEVER, THERE WAS NO ALT AND AIRSPD INDICATIONS ON STANDBY INSTS. WE ADVISED PIT DEP OF THE SIT. WE ASKED FOR VECTORS TO PIT AND DSCNT TO LOWEST POSSIBLE ALT. AT OR ABOUT 3000 FT, ALL INSTS CAME BACK. WE WERE VECTORED FOR RWY 28R APCH AND LANDED VISUALLY. ACFT WAS THOROUGHLY CHKED AND NOTHING WAS FOUND WRONG. ACFT IS BEING CHKED BY COMPANY AND FAIRCHILD TECHNICIANS. CAPT RPTS THAT AFTER INVESTIGATION BY THE ACFT MANUFACTURER, THEY CONCLUDED THE PROBE HEAT WAS NOT ON. THE CAPT REFUTES THIS AS THERE WAS NO EICAS PROBE HEAT WARNING. ALSO, THERE WAS NO BLUE ICE DETECTION WARNING LIGHT ILLUMINATED. THE CAPT STATED THAT THE PROB OCCURRED ONLY WHEN IN MODERATE TO HVY RAIN. THE OUTSIDE AIR TEMP WAS NEVER AT FREEZING OR BELOW. AS SOON AS THE ACFT DSNDED AND FLEW OUT OF THE RAIN THE PROBS STOPPED. IN CONVERSATION WITH THE ACR CHIEF PLT, HE INDICATED THAT THIS WAS A KNOWN PROB WITH THE TURBOPROP VERSION OF THE ACFT. THE CAPT ALSO KNOWS OF OTHER OCCURRENCES WITH THIS MODEL ACFT.

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.