Narrative:

While cruising at 5000 MSL in VMC conditions on night IFR plan, tops forecasted (PIREPS confirmed) 3500-4000 MSL, forecast for possible light rime on precipitation at the tops. I encountered IMC, requested and granted to climb to 7000 MSL. While cruising in VMC at 7000 MSL, I again encountered IMC conditions. I looked out at my wings and noted ice formation (clear rime) beginning. I called ATC (ZAU) immediately and was cleared for immediate 180 degree right turn. I decided to try to climb out of this unforecasted clouds and asked for and was granted 9000 MSL. Upon attempting to add power, I discovered I was developing carburetor ice. I immediately applied full carburetor heat. I then lost my pitot static system (while pitot heat had been on since leaving 5000 MSL) and immediately switched to alternate source and advised ATC. I was unable to climb and unable to maintain altitude. I declared an emergency due to icing and inability to maintain altitude. (Approximately 200 FPM loss.) ATC advised closest airport available due to WX as irk. I was vectored directly there. I wanted to maintain glide distance and opted to descend slowly to 3000 MSL. At approximately 3500 MSL I regained full engine power. I missed the approach to irk and while maneuvering for a second approach, an aircraft reported VFR condition at mcm approximately 20 mi south. I then flew directly there and landed without incident. During this, 2 commercial airliners in the flight levels reported (on the same ATC sector frequency) encountering unforecasted 100 KT headwinds. Prior to climbing to 7000, I asked center for tops but they were showing no precipitation in my area and therefore no returns. This situation might be prevented in the future if there were more WX radar installations across the country that could show cloud tops. Perhaps satellite information as well would help and more PIREPS.

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Original NASA ASRS Text

Title: SMA ENCOUNTERS AIRFRAME ICING AT NIGHT, LOSES ENG PWR AND DECLARES AN EMER.

Narrative: WHILE CRUISING AT 5000 MSL IN VMC CONDITIONS ON NIGHT IFR PLAN, TOPS FORECASTED (PIREPS CONFIRMED) 3500-4000 MSL, FORECAST FOR POSSIBLE LIGHT RIME ON PRECIPITATION AT THE TOPS. I ENCOUNTERED IMC, REQUESTED AND GRANTED TO CLB TO 7000 MSL. WHILE CRUISING IN VMC AT 7000 MSL, I AGAIN ENCOUNTERED IMC CONDITIONS. I LOOKED OUT AT MY WINGS AND NOTED ICE FORMATION (CLR RIME) BEGINNING. I CALLED ATC (ZAU) IMMEDIATELY AND WAS CLRED FOR IMMEDIATE 180 DEG R TURN. I DECIDED TO TRY TO CLB OUT OF THIS UNFORECASTED CLOUDS AND ASKED FOR AND WAS GRANTED 9000 MSL. UPON ATTEMPTING TO ADD PWR, I DISCOVERED I WAS DEVELOPING CARB ICE. I IMMEDIATELY APPLIED FULL CARB HEAT. I THEN LOST MY PITOT STATIC SYS (WHILE PITOT HEAT HAD BEEN ON SINCE LEAVING 5000 MSL) AND IMMEDIATELY SWITCHED TO ALTERNATE SOURCE AND ADVISED ATC. I WAS UNABLE TO CLB AND UNABLE TO MAINTAIN ALT. I DECLARED AN EMER DUE TO ICING AND INABILITY TO MAINTAIN ALT. (APPROX 200 FPM LOSS.) ATC ADVISED CLOSEST ARPT AVAILABLE DUE TO WX AS IRK. I WAS VECTORED DIRECTLY THERE. I WANTED TO MAINTAIN GLIDE DISTANCE AND OPTED TO DSND SLOWLY TO 3000 MSL. AT APPROX 3500 MSL I REGAINED FULL ENG PWR. I MISSED THE APCH TO IRK AND WHILE MANEUVERING FOR A SECOND APCH, AN ACFT RPTED VFR CONDITION AT MCM APPROX 20 MI S. I THEN FLEW DIRECTLY THERE AND LANDED WITHOUT INCIDENT. DURING THIS, 2 COMMERCIAL AIRLINERS IN THE FLT LEVELS RPTED (ON THE SAME ATC SECTOR FREQ) ENCOUNTERING UNFORECASTED 100 KT HEADWINDS. PRIOR TO CLBING TO 7000, I ASKED CENTER FOR TOPS BUT THEY WERE SHOWING NO PRECIPITATION IN MY AREA AND THEREFORE NO RETURNS. THIS SITUATION MIGHT BE PREVENTED IN THE FUTURE IF THERE WERE MORE WX RADAR INSTALLATIONS ACROSS THE COUNTRY THAT COULD SHOW CLOUD TOPS. PERHAPS SATELLITE INFO AS WELL WOULD HELP AND MORE PIREPS.

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.