Narrative:

Filed an IFR flight plan gck direct ALS J110 las direct vgt. Approximately 75 NM west of gck, I requested 30 degree deviation south of course to navigate around some level iv and level V thunderstorms which were forecast and showing on my stormscope. Shortly thereafter I asked for and received another 30 degree deviation south of course (approximately heading now 180) to continue to stay well southeast of thunderstorm activity. About 60 northeast of cim, I started to proceed direct fnm (my new clearance) and was talking with abq center on 132.8. I heard an air carrier flight at FL240 call and report mod icing and knew he was in vicinity but didn't know how close to my position. About 10 mins later, in IMC at FL180 I started to experience mod icing and requested lower altitude. Center sent me down to 17,000 and said it would be 15 NM before lower could be expected. I didn't feel, at this point, that a 180 degree turn would be the best option since I had just gone through the worst of the icing. Called center back and insisted on lower altitude and recommended direction. All this time, they were aware of my icing problem. Finally cleared to 16,000 and requested lower and vectors to better conditions. Vectored to heading of 180 degree which I immediately turned to and then controller came back and said he wanted 240 degree instead of original 180 heading. Told him I was having trouble holding altitude, was going to maintain 180 degree (since I saw a break in the WX and clear air at my 12 O'clock position) and I was going lower since I could see the ground and the situation wasn't getting any better at 16,000. When I leveled at 12,000 I contacted center and asked to proceed VFR to closest airport (which I did). I circled until ice melted, landed to check the airplane and then refiled to resume the flight. 1) although I should have and could have asked, controller should have volunteered position of air carrier flight to all flts in the vicinity. 2) a change of 60 degree in a given heading (from 180 to 240) destroyed my remaining confidence in the controller because the 240 heading was virtually the same heading I was asking to get away from.

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Original NASA ASRS Text

Title: GA SMA INFLT ENCOUNTER WITH ICING AT 18,000'.

Narrative: FILED AN IFR FLT PLAN GCK DIRECT ALS J110 LAS DIRECT VGT. APPROX 75 NM W OF GCK, I REQUESTED 30 DEG DEVIATION S OF COURSE TO NAVIGATE AROUND SOME LEVEL IV AND LEVEL V TSTMS WHICH WERE FORECAST AND SHOWING ON MY STORMSCOPE. SHORTLY THEREAFTER I ASKED FOR AND RECEIVED ANOTHER 30 DEG DEVIATION S OF COURSE (APPROX HDG NOW 180) TO CONTINUE TO STAY WELL SE OF TSTM ACTIVITY. ABOUT 60 NE OF CIM, I STARTED TO PROCEED DIRECT FNM (MY NEW CLRNC) AND WAS TALKING WITH ABQ CENTER ON 132.8. I HEARD AN ACR FLT AT FL240 CALL AND REPORT MOD ICING AND KNEW HE WAS IN VICINITY BUT DIDN'T KNOW HOW CLOSE TO MY POSITION. ABOUT 10 MINS LATER, IN IMC AT FL180 I STARTED TO EXPERIENCE MOD ICING AND REQUESTED LOWER ALT. CENTER SENT ME DOWN TO 17,000 AND SAID IT WOULD BE 15 NM BEFORE LOWER COULD BE EXPECTED. I DIDN'T FEEL, AT THIS POINT, THAT A 180 DEG TURN WOULD BE THE BEST OPTION SINCE I HAD JUST GONE THROUGH THE WORST OF THE ICING. CALLED CENTER BACK AND INSISTED ON LOWER ALT AND RECOMMENDED DIRECTION. ALL THIS TIME, THEY WERE AWARE OF MY ICING PROBLEM. FINALLY CLRED TO 16,000 AND REQUESTED LOWER AND VECTORS TO BETTER CONDITIONS. VECTORED TO HDG OF 180 DEG WHICH I IMMEDIATELY TURNED TO AND THEN CTLR CAME BACK AND SAID HE WANTED 240 DEG INSTEAD OF ORIGINAL 180 HDG. TOLD HIM I WAS HAVING TROUBLE HOLDING ALT, WAS GOING TO MAINTAIN 180 DEG (SINCE I SAW A BREAK IN THE WX AND CLEAR AIR AT MY 12 O'CLOCK POSITION) AND I WAS GOING LOWER SINCE I COULD SEE THE GND AND THE SITUATION WASN'T GETTING ANY BETTER AT 16,000. WHEN I LEVELED AT 12,000 I CONTACTED CENTER AND ASKED TO PROCEED VFR TO CLOSEST ARPT (WHICH I DID). I CIRCLED UNTIL ICE MELTED, LANDED TO CHECK THE AIRPLANE AND THEN REFILED TO RESUME THE FLT. 1) ALTHOUGH I SHOULD HAVE AND COULD HAVE ASKED, CTLR SHOULD HAVE VOLUNTEERED POSITION OF ACR FLT TO ALL FLTS IN THE VICINITY. 2) A CHANGE OF 60 DEG IN A GIVEN HDG (FROM 180 TO 240) DESTROYED MY REMAINING CONFIDENCE IN THE CTLR BECAUSE THE 240 HDG WAS VIRTUALLY THE SAME HDG I WAS ASKING TO GET AWAY FROM.

Data retrieved from NASA's ASRS site as of August 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.