PLT OF AN SMA SEL PVT ACFT DEVIATED FROM ASSIGNED HDG WHILE ATTEMPTING TO GET OUT OF ICING CONDITIONS.

Narrative

ON THE MORNING NOTED ABOVE I OBTAINED A FLT BRIEFING. I INITIATED A VFR FLT FROM OXC TO MVY AT APPROX XA00 AM. WHEN I WAS APPROX 30 MI W AND N OF NEW LONDON; I NOTICED THAT I WAS ENCOUNTERING CLOUDS AHEAD OF ME ALTHOUGH I WAS STILL VFR. I CALLED NEW YORK ON 126.95 AND ASKED FOR AN INST CLRNC; BOTH MYSELF AND THE AIRPLANE BEING INST CERTIFIED. AFTER A VERY SHORT DELAY; I WAS GIVEN A CLRNC. I ENTERED THE CLOUDS A FEW MOMENTS LATER. WITHIN ABOUT 60-120 SECONDS I BEGAN TO NOTICE AN EXTREMELY RAPID ICE BUILD-UP ON THE WINDSCREEN AND LEADING EDGES OF THE WINGS; APPROX 3/4 - 1 INCH. I CALLED THE CTLR AND TOLD HIM THAT I HAD A RAPID ICE BUILD-UP AND I WOULD HAVE TO GO DOWN TO ABOUT 3000 FT (KNOWING THE CEILING WAS APPROX 3000 FT IN THAT AREA FROM RPTS) AND WOULD EXECUTE A 180 TO GET BACK INTO CLR CONDITIONS. THE CTLR TOLD ME THAT I 'COULDN'T' DO THAT BECAUSE I HAD TFC. HE RECOMMENDED A CLB TO 7000 FT; SAYING THAT THE TOPS WERE AT 7000 FT. ALTHOUGH I INITIALLY ACKNOWLEDGED AND BEGAN TO CLB; I REALIZED THAT WITH ICE BUILDING RAPIDLY THAT THIS WAS AN UNSAFE MANEUVER AND CALLED THE CTLR BACK AND SAID THAT I NEEDED TO LOSE ALT AND REVERSE DIRECTION QUICKLY. HE GAVE ME A HDG OF 360 DEGS AND CLRED ME TO 3000 FT. I TOOK THIS HDG AND BEGAN TO LOSE ALT AND THEN CALLED HIM AND TOLD HIM THAT I WAS TURNING TO 270 DEGS. AT THIS POINT I AM NOT SURE WHETHER HE ACTUALLY CLRED ME TO 270 DEGS OR SIMPLY ACKNOWLEDGED THE FACT THAT I WAS MAKING MY OWN DECISION; AND THAT IS THE REASON THAT I'M FILING THIS RPT. AT ANY RATE; I BROKE OUT OF THE CLOUDS AT 3000 FT; I TURNED BACK TO THE E TO TRY TO FLY TO MARTHA'S VINEYARD UNDERNEATH; AND AS THE CEILING GOT LOWER I REALIZED THAT THIS WAS NOT A PRUDENT FLT AND TURNED BACK TO OXFORD. AFTER 1/2 HR OR SO IN THE CLR; WHEN I LANDED I STILL HAD A MINIMUM OF 1/2 INCH OF ICE ON ALL LEADING EDGES; COWL; WHEEL FAIRINGS; ETC.