Narrative:

IFR flight ZZZ-ZZZZ. Broken clouds 3500 ft up to 6000 ft. Filed at 6000 ft. Turbulent air with s-tec autoplt not adequately holding altitude due to turbulence or malfunction. Tried to see if autoplt would correct but would turn off +/-200 ft. Not sure why it could not hold adequate altitude. Finally switched to manual flying. Shortly thereafter noticed significant decrease in maneuverability and slight loss of speed. Noticed significantly mixed ice on leading edge of wings. Was just at bases; dropped out of clouds. ATC was called. I informed them of my condition; asked for lower. Informed 350 ft below assigned altitude. Stayed out of clouds. Ice eventually melted; flew off. Landed without problem. 1) should have flown above the clouds: VMC. 2) when having trouble with autoplt; should have informed ATC and asked for a block altitude. 3) with ice should have declared emergency to ATC; if not able to give immediate lower altitude. 4) was at flying camp in canada for 1 week; otherwise would have filed earlier.

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Original NASA ASRS Text

Title: AN IMC LANCAIR ACCUMULATED ICE IN CLOUD BASES AND EXPERIENCES ACFT CTL PROBLEMS. CLEARANCE TO A LOWER ALT REMOVED THE ICE.

Narrative: IFR FLT ZZZ-ZZZZ. BROKEN CLOUDS 3500 FT UP TO 6000 FT. FILED AT 6000 FT. TURBULENT AIR WITH S-TEC AUTOPLT NOT ADEQUATELY HOLDING ALT DUE TO TURB OR MALFUNCTION. TRIED TO SEE IF AUTOPLT WOULD CORRECT BUT WOULD TURN OFF +/-200 FT. NOT SURE WHY IT COULD NOT HOLD ADEQUATE ALT. FINALLY SWITCHED TO MANUAL FLYING. SHORTLY THEREAFTER NOTICED SIGNIFICANT DECREASE IN MANEUVERABILITY AND SLIGHT LOSS OF SPD. NOTICED SIGNIFICANTLY MIXED ICE ON LEADING EDGE OF WINGS. WAS JUST AT BASES; DROPPED OUT OF CLOUDS. ATC WAS CALLED. I INFORMED THEM OF MY CONDITION; ASKED FOR LOWER. INFORMED 350 FT BELOW ASSIGNED ALT. STAYED OUT OF CLOUDS. ICE EVENTUALLY MELTED; FLEW OFF. LANDED WITHOUT PROB. 1) SHOULD HAVE FLOWN ABOVE THE CLOUDS: VMC. 2) WHEN HAVING TROUBLE WITH AUTOPLT; SHOULD HAVE INFORMED ATC AND ASKED FOR A BLOCK ALT. 3) WITH ICE SHOULD HAVE DECLARED EMER TO ATC; IF NOT ABLE TO GIVE IMMEDIATE LOWER ALT. 4) WAS AT FLYING CAMP IN CANADA FOR 1 WK; OTHERWISE WOULD HAVE FILED EARLIER.

Data retrieved from NASA's ASRS site as of January 2009 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.