Narrative:

After a wkend with grandchildren; spouse and I scheduled a return departing ZZZ3 at XA00. I checked WX the previous afternoon and filed IFR. I also checked adds; duats; NOAA WX on-line products; and the cnn news WX reports. High pressure was over my route of flight with moderate turbulence forecast. Before departing; I checked the on-line computer at ZZZ3 and noted no significant WX. Freezing levels were at 6000 ft; but with high pressure and no rain in the forecast I was not concerned with temperatures. At 8000 ft MSL; I was in heavy haze but could see the ground. After about 1 hour; I was in more cloud than haze; but there was no precipitation. I received handoff to ZZZ1 at which time I asked to be off-line to check in with FSS. FSS informed me of conditions in the area with icing conditions at my flight level. While on-line with FSS; I went from instant no ice condition to an opaque iced windshield. I thanked FSS and immediately went back to ZZZ1 and reported my problem and asked for lower altitude. Not wanting to continue into adverse conditions; I told ZZZ1 I would like lower and an immediate 360 degree turn. (I meant a 180 degree reversal of course.) after what seemed like more than appropriate time and still picking up ice; I turned 180 degrees; maintaining 8000 ft without clearance to do so. ZZZ1 then came on line; asked my heading; and cleared me to 6000 ft and issued a more westerly heading. After a few mins; I was then handed back to ZZZ2. ZZZ2 did a fantastic job of giving me headings and altitudes that would get me out of the icing conditions and help me shed the buildup I had. I was over mountainous terrain and was limited to available options. There was some confusion as to headings and at times I stopped at altitudes between layers instead of the assigned altitude. Although I was not given clearance for each action; I did; however; inform ZZZ2 of my altitudes and headings. I was asked of my intentions after losing the ice. I indicated that I would like to continue the flight if there was a route outside of icing conditions. After reaching 3800 ft and the ice was finally gone; ZZZ2 suggested a route where conditions were more favorable. The remaining flight was uneventful. There are many lessons to be learned from this experience. The first is in the preflight planning. I assumed good WX from reports; but listened to only the portions I wanted to hear. Experience should have told me a high pressure is often cloudy and when conditions are forecast to be unstable with turbulence; precipitation is likely. A last call to FSS would have given additional information. Then there is recognizing icing conditions prior to conditions that could jeopardize safety. When I saw that the temperatures were near zero; it was time to take positive and immediate action. Not wait until potential danger could occur. The flight 3 days before had been planned to avoid WX by going around the mountains to the southeast. The same concept should have been used on the return trip. Instead; I elected to take a faster direct route home. Poor judgement. After icing conditions occurred; my focus was on getting rid of the ice. I did not completely follow directions by ATC. Unless I was in conditions where an emergency needed to be declared; ATC instructions should be strictly adhered to. When my conditions changed; I should have waited for clearance before changing my altitude or heading.

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Original NASA ASRS Text

Title: AN IFR C182RG PLT ENCOUNTERED ICE AT HIS FILED 8000 FT ALT AND DIVERTED OFF AIRWAYS WHILE DSNDING CLR OF ICE.

Narrative: AFTER A WKEND WITH GRANDCHILDREN; SPOUSE AND I SCHEDULED A RETURN DEPARTING ZZZ3 AT XA00. I CHKED WX THE PREVIOUS AFTERNOON AND FILED IFR. I ALSO CHKED ADDS; DUATS; NOAA WX ON-LINE PRODUCTS; AND THE CNN NEWS WX RPTS. HIGH PRESSURE WAS OVER MY RTE OF FLT WITH MODERATE TURB FORECAST. BEFORE DEPARTING; I CHKED THE ON-LINE COMPUTER AT ZZZ3 AND NOTED NO SIGNIFICANT WX. FREEZING LEVELS WERE AT 6000 FT; BUT WITH HIGH PRESSURE AND NO RAIN IN THE FORECAST I WAS NOT CONCERNED WITH TEMPS. AT 8000 FT MSL; I WAS IN HVY HAZE BUT COULD SEE THE GND. AFTER ABOUT 1 HR; I WAS IN MORE CLOUD THAN HAZE; BUT THERE WAS NO PRECIP. I RECEIVED HDOF TO ZZZ1 AT WHICH TIME I ASKED TO BE OFF-LINE TO CHK IN WITH FSS. FSS INFORMED ME OF CONDITIONS IN THE AREA WITH ICING CONDITIONS AT MY FLT LEVEL. WHILE ON-LINE WITH FSS; I WENT FROM INSTANT NO ICE CONDITION TO AN OPAQUE ICED WINDSHIELD. I THANKED FSS AND IMMEDIATELY WENT BACK TO ZZZ1 AND RPTED MY PROB AND ASKED FOR LOWER ALT. NOT WANTING TO CONTINUE INTO ADVERSE CONDITIONS; I TOLD ZZZ1 I WOULD LIKE LOWER AND AN IMMEDIATE 360 DEG TURN. (I MEANT A 180 DEG REVERSAL OF COURSE.) AFTER WHAT SEEMED LIKE MORE THAN APPROPRIATE TIME AND STILL PICKING UP ICE; I TURNED 180 DEGS; MAINTAINING 8000 FT WITHOUT CLRNC TO DO SO. ZZZ1 THEN CAME ON LINE; ASKED MY HDG; AND CLRED ME TO 6000 FT AND ISSUED A MORE WESTERLY HDG. AFTER A FEW MINS; I WAS THEN HANDED BACK TO ZZZ2. ZZZ2 DID A FANTASTIC JOB OF GIVING ME HDGS AND ALTS THAT WOULD GET ME OUT OF THE ICING CONDITIONS AND HELP ME SHED THE BUILDUP I HAD. I WAS OVER MOUNTAINOUS TERRAIN AND WAS LIMITED TO AVAILABLE OPTIONS. THERE WAS SOME CONFUSION AS TO HDGS AND AT TIMES I STOPPED AT ALTS BTWN LAYERS INSTEAD OF THE ASSIGNED ALT. ALTHOUGH I WAS NOT GIVEN CLRNC FOR EACH ACTION; I DID; HOWEVER; INFORM ZZZ2 OF MY ALTS AND HDGS. I WAS ASKED OF MY INTENTIONS AFTER LOSING THE ICE. I INDICATED THAT I WOULD LIKE TO CONTINUE THE FLT IF THERE WAS A RTE OUTSIDE OF ICING CONDITIONS. AFTER REACHING 3800 FT AND THE ICE WAS FINALLY GONE; ZZZ2 SUGGESTED A RTE WHERE CONDITIONS WERE MORE FAVORABLE. THE REMAINING FLT WAS UNEVENTFUL. THERE ARE MANY LESSONS TO BE LEARNED FROM THIS EXPERIENCE. THE FIRST IS IN THE PREFLT PLANNING. I ASSUMED GOOD WX FROM RPTS; BUT LISTENED TO ONLY THE PORTIONS I WANTED TO HEAR. EXPERIENCE SHOULD HAVE TOLD ME A HIGH PRESSURE IS OFTEN CLOUDY AND WHEN CONDITIONS ARE FORECAST TO BE UNSTABLE WITH TURB; PRECIP IS LIKELY. A LAST CALL TO FSS WOULD HAVE GIVEN ADDITIONAL INFO. THEN THERE IS RECOGNIZING ICING CONDITIONS PRIOR TO CONDITIONS THAT COULD JEOPARDIZE SAFETY. WHEN I SAW THAT THE TEMPS WERE NEAR ZERO; IT WAS TIME TO TAKE POSITIVE AND IMMEDIATE ACTION. NOT WAIT UNTIL POTENTIAL DANGER COULD OCCUR. THE FLT 3 DAYS BEFORE HAD BEEN PLANNED TO AVOID WX BY GOING AROUND THE MOUNTAINS TO THE SE. THE SAME CONCEPT SHOULD HAVE BEEN USED ON THE RETURN TRIP. INSTEAD; I ELECTED TO TAKE A FASTER DIRECT RTE HOME. POOR JUDGEMENT. AFTER ICING CONDITIONS OCCURRED; MY FOCUS WAS ON GETTING RID OF THE ICE. I DID NOT COMPLETELY FOLLOW DIRECTIONS BY ATC. UNLESS I WAS IN CONDITIONS WHERE AN EMER NEEDED TO BE DECLARED; ATC INSTRUCTIONS SHOULD BE STRICTLY ADHERED TO. WHEN MY CONDITIONS CHANGED; I SHOULD HAVE WAITED FOR CLRNC BEFORE CHANGING MY ALT OR HDG.

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.