Narrative:

I was flying solo in cessna 150 from fort wayne, in (fwa) to louisville, ky (lou) on an IFR flight plan at night. The WX was forecast to be IMC across the entire route with icing possible at 6000 ft and above, so I filed for 4000 ft. The first half of the flight was uneventful, but then I started to pick up light rime ice. I requested 3000 ft, hoping the temperature would be warm enough at that altitude to melt the ice and keep additional ice from accumulating. I was still picking up light rime ice at 3000 ft so I requested lower. The center controller cleared me to 2600 ft which was the lowest he could allow me to go. I didn't get much better at that altitude. Then I was told to change to louisville approach and that they wanted me at 3000 ft. I was unable to climb to 3000 ft as my airspeed had slowed to about 65 KTS in level flight. In addition, louisville approach could not hear my transmission even though I could hear them calling me. I decided to divert to madison, in, and try to land there. I had not been cleared to madison, but since I was unable to contact louisville approach to make the request, I felt it was necessary to divert given my icing situation. The diversion took me about 5 mi off my course to louisville. When I got over madison, my airspeed had increased about 5 KTS and it seemed as though the ice was melting somewhat, so I decided to continue to louisville. I was finally able to contact louisville approach, but was unable to climb above 2600 ft. I felt that my first, and biggest, error was making the choice to fly at all that night. I justified making the flight because the forecast called for ice at altitudes higher than I planned to fly. I also wanted very much to get home that night. However, I should have considered the chance that icing might also affect lower altitudes. Since the airplane I was flying was not ice protected I should not have attempted the flight. My second error was not requesting a lower altitude sooner or requesting a turn back to an airport where I knew that icing wasn't a problem. I waited too long and accumulated too much ice before I finally made any requests.

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Original NASA ASRS Text

Title: AN ATP, FLYING A C150 IN THE DARK IN ICING CONDITIONS, COMMITTED BOTH AN ALTDEV AND A HEADING DEV IN SDF'S AIRSPACE.

Narrative: I WAS FLYING SOLO IN CESSNA 150 FROM FORT WAYNE, IN (FWA) TO LOUISVILLE, KY (LOU) ON AN IFR FLT PLAN AT NIGHT. THE WX WAS FORECAST TO BE IMC ACROSS THE ENTIRE RTE WITH ICING POSSIBLE AT 6000 FT AND ABOVE, SO I FILED FOR 4000 FT. THE FIRST HALF OF THE FLT WAS UNEVENTFUL, BUT THEN I STARTED TO PICK UP LIGHT RIME ICE. I REQUESTED 3000 FT, HOPING THE TEMP WOULD BE WARM ENOUGH AT THAT ALT TO MELT THE ICE AND KEEP ADDITIONAL ICE FROM ACCUMULATING. I WAS STILL PICKING UP LIGHT RIME ICE AT 3000 FT SO I REQUESTED LOWER. THE CTR CTLR CLRED ME TO 2600 FT WHICH WAS THE LOWEST HE COULD ALLOW ME TO GO. I DIDN'T GET MUCH BETTER AT THAT ALT. THEN I WAS TOLD TO CHANGE TO LOUISVILLE APCH AND THAT THEY WANTED ME AT 3000 FT. I WAS UNABLE TO CLB TO 3000 FT AS MY AIRSPD HAD SLOWED TO ABOUT 65 KTS IN LEVEL FLT. IN ADDITION, LOUISVILLE APCH COULD NOT HEAR MY XMISSION EVEN THOUGH I COULD HEAR THEM CALLING ME. I DECIDED TO DIVERT TO MADISON, IN, AND TRY TO LAND THERE. I HAD NOT BEEN CLRED TO MADISON, BUT SINCE I WAS UNABLE TO CONTACT LOUISVILLE APCH TO MAKE THE REQUEST, I FELT IT WAS NECESSARY TO DIVERT GIVEN MY ICING SIT. THE DIVERSION TOOK ME ABOUT 5 MI OFF MY COURSE TO LOUISVILLE. WHEN I GOT OVER MADISON, MY AIRSPD HAD INCREASED ABOUT 5 KTS AND IT SEEMED AS THOUGH THE ICE WAS MELTING SOMEWHAT, SO I DECIDED TO CONTINUE TO LOUISVILLE. I WAS FINALLY ABLE TO CONTACT LOUISVILLE APCH, BUT WAS UNABLE TO CLB ABOVE 2600 FT. I FELT THAT MY FIRST, AND BIGGEST, ERROR WAS MAKING THE CHOICE TO FLY AT ALL THAT NIGHT. I JUSTIFIED MAKING THE FLT BECAUSE THE FORECAST CALLED FOR ICE AT ALTS HIGHER THAN I PLANNED TO FLY. I ALSO WANTED VERY MUCH TO GET HOME THAT NIGHT. HOWEVER, I SHOULD HAVE CONSIDERED THE CHANCE THAT ICING MIGHT ALSO AFFECT LOWER ALTS. SINCE THE AIRPLANE I WAS FLYING WAS NOT ICE PROTECTED I SHOULD NOT HAVE ATTEMPTED THE FLT. MY SECOND ERROR WAS NOT REQUESTING A LOWER ALT SOONER OR REQUESTING A TURN BACK TO AN ARPT WHERE I KNEW THAT ICING WASN'T A PROB. I WAITED TOO LONG AND ACCUMULATED TOO MUCH ICE BEFORE I FINALLY MADE ANY REQUESTS.

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.