Narrative:

I was flying an small aircraft at 11000 on an IFR flight in IMC conditions when I encountered light rime ice on the leading edge of the wings. I explained the situation to the air traffic controller and asked if could descend to 9000 ft. The controller cleared me to descend to 9500. At 9500 the temperature was 0 degrees C and while no more ice was accumulating on the wings, it was not defrosting either. While discussing with ATC the possibility of diverting south to san marcos (rzs) VOR along V-25 (where the MEA is 8600) and then direct vtu, lax, and finally to lgb, I hit an updraft which caused the aircraft to climb. While approaching 10500 ft, I asked ATC if I could climb to 11000 ft. At 11000 it was VFR, between 2 layers of clouds. The controller asked me what my present altitude was. I told him 10500. He asked me who gave me permission to climb to 10500. I paused, then replied by explaining how an updraft caused me to climb and I continued to 10500 which was clear of clouds. The controller scolded me for climbing without permission and cleared me back to 11000 where it was VFR. I thanked him for his help and changed frequencys to the next controller. It was clear to me, as a pilot, it was more important to reach an altitude that was clear of clouds and moisture to stop the build-up of ice, than to continue to make a marginal situation worse. I could not control the air mass that caused the aircraft to climb initially. When I got out of the updraft, I was only a couple hundred ft from 10500, and more importantly, a couple hundred ft from VFR conditions. I climbed to 10500 because the aerodynamics of an airplane are much better than an ice cube.

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Original NASA ASRS Text

Title: ALTDEV AFTER INFLT ENCOUNTER WITH ADVERSE ENRTE WX FACTORS.

Narrative: I WAS FLYING AN SMA AT 11000 ON AN IFR FLT IN IMC CONDITIONS WHEN I ENCOUNTERED LIGHT RIME ICE ON THE LEADING EDGE OF THE WINGS. I EXPLAINED THE SIT TO THE AIR TFC CTLR AND ASKED IF COULD DSND TO 9000 FT. THE CTLR CLRED ME TO DSND TO 9500. AT 9500 THE TEMP WAS 0 DEGS C AND WHILE NO MORE ICE WAS ACCUMULATING ON THE WINGS, IT WAS NOT DEFROSTING EITHER. WHILE DISCUSSING WITH ATC THE POSSIBILITY OF DIVERTING S TO SAN MARCOS (RZS) VOR ALONG V-25 (WHERE THE MEA IS 8600) AND THEN DIRECT VTU, LAX, AND FINALLY TO LGB, I HIT AN UPDRAFT WHICH CAUSED THE ACFT TO CLB. WHILE APCHING 10500 FT, I ASKED ATC IF I COULD CLB TO 11000 FT. AT 11000 IT WAS VFR, BTWN 2 LAYERS OF CLOUDS. THE CTLR ASKED ME WHAT MY PRESENT ALT WAS. I TOLD HIM 10500. HE ASKED ME WHO GAVE ME PERMISSION TO CLB TO 10500. I PAUSED, THEN REPLIED BY EXPLAINING HOW AN UPDRAFT CAUSED ME TO CLB AND I CONTINUED TO 10500 WHICH WAS CLR OF CLOUDS. THE CTLR SCOLDED ME FOR CLBING WITHOUT PERMISSION AND CLRED ME BACK TO 11000 WHERE IT WAS VFR. I THANKED HIM FOR HIS HELP AND CHANGED FREQS TO THE NEXT CTLR. IT WAS CLR TO ME, AS A PLT, IT WAS MORE IMPORTANT TO REACH AN ALT THAT WAS CLR OF CLOUDS AND MOISTURE TO STOP THE BUILD-UP OF ICE, THAN TO CONTINUE TO MAKE A MARGINAL SIT WORSE. I COULD NOT CTL THE AIR MASS THAT CAUSED THE ACFT TO CLB INITIALLY. WHEN I GOT OUT OF THE UPDRAFT, I WAS ONLY A COUPLE HUNDRED FT FROM 10500, AND MORE IMPORTANTLY, A COUPLE HUNDRED FT FROM VFR CONDITIONS. I CLBED TO 10500 BECAUSE THE AERODYNAMICS OF AN AIRPLANE ARE MUCH BETTER THAN AN ICE CUBE.

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.