Narrative:

IFR flight from ssi the weather briefing showed a convective sigmet across the route of flight. No icing airmets were shown for the route. The plane is not equipped for flight into icing; it has only a heated pitot tube and windshield defroster. The radar showed isolated cells with light to extreme precipitation within the area of the convective sigmet. The precipitation cells seemed far enough apart to navigate in between them with help from ATC. After reaching the assigned altitude of FL190 I advised ATC that I needed to deviate to the right (west) because of a cloud build up ahead of me. I got clearance for 15 degrees to the right. The controller advised me that I could have more than that if needed. After another 20 NM I entered IMC conditions which seemed fairly thin and did not look like a build up. I requested FL210 which got approved. During the climb I encountered heavy precipitation and very fast clear ice build up. The airplane is not equipped with anti icing equipment. Within 30 seconds the leading edge had about 1 inch of ice accumulated. I advised ATC about icing and precipitation. I got permission for deviation to the east and 11;000 ft; below freezing level. At this time the autopilot had flown the plane almost into a stall - the angle of attack indicator turned completely red and I got the warning in the head set. I disengaged the autopilot and pushed the nose down and turned to the east. The precipitation lasted only about 1 minute. Reaching 18;000 the airspeed was built up again and the fast clear ice build up had stopped. I advised ATC that I did not need to descend to 11;000. I got FL190 climbed to FL190 and stabilized the plane and engaged the autopilot. I entered VFR conditions shortly after this. I had about 1 inch of ice on the leading edge of the wing which looked now like rime ice. I advised ATC that everything was under control and that the flight would be continued. The ice on the wing disappeared slowly in the VFR conditions in the sun.

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Original NASA ASRS Text

Title: Lancair 4 pilot reports entering icing conditions climbing from FL190 to FL210. The ice build up is rapid and the aircraft is not equipped for flight into known icing condition. A descent is quickly requested and granted as the aircraft is running out of airspeed. At 18;000 FT the airspeed has built back up and no more ice accumulation is experienced. Reporter continues to destination with almost one inch of ice on the leading edge that slowly melts.

Narrative: IFR flight from SSI the weather briefing showed a convective sigmet across the route of flight. No icing airmets were shown for the route. The plane is not equipped for flight into icing; it has only a heated pitot tube and windshield defroster. The radar showed isolated cells with light to extreme precipitation within the area of the convective sigmet. The precipitation cells seemed far enough apart to navigate in between them with help from ATC. After reaching the assigned altitude of FL190 I advised ATC that I needed to deviate to the right (west) because of a cloud build up ahead of me. I got clearance for 15 degrees to the right. The controller advised me that I could have more than that if needed. After another 20 NM I entered IMC conditions which seemed fairly thin and did not look like a build up. I requested FL210 which got approved. During the climb I encountered heavy precipitation and very fast clear ice build up. The airplane is not equipped with anti icing equipment. Within 30 seconds the leading edge had about 1 inch of ice accumulated. I advised ATC about icing and precipitation. I got permission for deviation to the east and 11;000 FT; below freezing level. At this time the autopilot had flown the plane almost into a stall - the angle of attack indicator turned completely red and I got the warning in the head set. I disengaged the autopilot and pushed the nose down and turned to the east. The precipitation lasted only about 1 minute. Reaching 18;000 the airspeed was built up again and the fast clear ice build up had stopped. I advised ATC that I did not need to descend to 11;000. I got FL190 climbed to FL190 and stabilized the plane and engaged the autopilot. I entered VFR conditions shortly after this. I had about 1 inch of ice on the leading edge of the wing which looked now like rime ice. I advised ATC that everything was under control and that the flight would be continued. The ice on the wing disappeared slowly in the VFR conditions in the sun.

Data retrieved from NASA's ASRS site as of July 2013 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.