Narrative:

Departing from modesto, ca, (mod) I filed for V23 to san diego montgomery (myf). Based on the WX briefings and terrain features on the sectional, I figured this had the lowest MEA's for ice avoidance, keep me in the mildest WX and connect with areas of VFR PIREPS. When taxiing out my clearance was given as V107 from panoche (pxn) to avenal (ave) which runs along a mountain ridge. I checked MEA's on the route at 7000 ft which was less than the forecast 8000-11000 ft freezing level and figured the route could work. I stayed at 7000 ft until I was clear of clouds with a temperature of +1 degree C. I went up to 9000 ft and then 11000 ft to stay clear of the clouds. Approaching avenal (ave) with temperatures at -1 degree C at 11000 ft, I was unsure that I could stay clear of clouds. I was going to ask for direct shafter (ehf) which could have kept me clear of clouds, but I had to switch from ZOA to ZLA. By the time I made contact I was in the clouds very near avenal and about to make my clearance required turn to shafter. This is when I picked up a trace of ice (about 1 MM of rime less than 1/8 inch). I asked for lower and was given 9000 ft. I broke out of the clouds but the ice stayed on. I asked for lower and was switched to bakersfield approach who gave me 5000 ft which finally melted the ice. The ice could have been avoided if I had been given the V23 route that I had planned. Getting amended clrncs that are substantially different from planned routes makes it hard to follow a WX avoidance plan. Also if the WX briefers had the preferred routings, I could have figured out and filed for a WX avoidance route that I would have been given a clearance for. This would be especially helpful in unfamiliar areas.

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Original NASA ASRS Text

Title: GA PLT OF SMA ENCOUNTERS RIME ICING.

Narrative: DEPARTING FROM MODESTO, CA, (MOD) I FILED FOR V23 TO SAN DIEGO MONTGOMERY (MYF). BASED ON THE WX BRIEFINGS AND TERRAIN FEATURES ON THE SECTIONAL, I FIGURED THIS HAD THE LOWEST MEA'S FOR ICE AVOIDANCE, KEEP ME IN THE MILDEST WX AND CONNECT WITH AREAS OF VFR PIREPS. WHEN TAXIING OUT MY CLRNC WAS GIVEN AS V107 FROM PANOCHE (PXN) TO AVENAL (AVE) WHICH RUNS ALONG A MOUNTAIN RIDGE. I CHKED MEA'S ON THE RTE AT 7000 FT WHICH WAS LESS THAN THE FORECAST 8000-11000 FT FREEZING LEVEL AND FIGURED THE RTE COULD WORK. I STAYED AT 7000 FT UNTIL I WAS CLR OF CLOUDS WITH A TEMP OF +1 DEG C. I WENT UP TO 9000 FT AND THEN 11000 FT TO STAY CLR OF THE CLOUDS. APCHING AVENAL (AVE) WITH TEMPS AT -1 DEG C AT 11000 FT, I WAS UNSURE THAT I COULD STAY CLR OF CLOUDS. I WAS GOING TO ASK FOR DIRECT SHAFTER (EHF) WHICH COULD HAVE KEPT ME CLR OF CLOUDS, BUT I HAD TO SWITCH FROM ZOA TO ZLA. BY THE TIME I MADE CONTACT I WAS IN THE CLOUDS VERY NEAR AVENAL AND ABOUT TO MAKE MY CLRNC REQUIRED TURN TO SHAFTER. THIS IS WHEN I PICKED UP A TRACE OF ICE (ABOUT 1 MM OF RIME LESS THAN 1/8 INCH). I ASKED FOR LOWER AND WAS GIVEN 9000 FT. I BROKE OUT OF THE CLOUDS BUT THE ICE STAYED ON. I ASKED FOR LOWER AND WAS SWITCHED TO BAKERSFIELD APCH WHO GAVE ME 5000 FT WHICH FINALLY MELTED THE ICE. THE ICE COULD HAVE BEEN AVOIDED IF I HAD BEEN GIVEN THE V23 RTE THAT I HAD PLANNED. GETTING AMENDED CLRNCS THAT ARE SUBSTANTIALLY DIFFERENT FROM PLANNED ROUTES MAKES IT HARD TO FOLLOW A WX AVOIDANCE PLAN. ALSO IF THE WX BRIEFERS HAD THE PREFERRED ROUTINGS, I COULD HAVE FIGURED OUT AND FILED FOR A WX AVOIDANCE RTE THAT I WOULD HAVE BEEN GIVEN A CLRNC FOR. THIS WOULD BE ESPECIALLY HELPFUL IN UNFAMILIAR AREAS.

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.