POTENTIAL CONFLICT WHILE DEVIATING WX ON A VFR FLT PLAN.

Narrative

WHILE CLBING TO 11500' CHATTANOOGA APCH HAD ME HOLD AT 10000' TO ARRANGE A HDOF TO ZTL. I WAS CLRED TO 11500' AND HANDED OFF TO CENTER. WHEN 84 NM FROM DEST (SALEM; SC); AFTER HAVING RECEIVED A CLRNC TO DSND TO DEST MAINTAINING VFR; DSNDING THROUGH 8800' GOT A GLANCE OF A LIGHT TWIN PASSING ABOVE AND OFF TO THE RIGHT. MY HDG WAS APPROX 90 DEGS. ESTIMATE THE OTHER ACFT TO BE LEVEL AT 9000'; HDG 290 DEGS. I WAS CIRCUMNAVING CLOUDS AND THE HDG MIGHT NOT HAVE BEEN EXACTLY 90 DEGS. THERE IS A POSSIBILITY THE OTHER ACFT COULD HAVE BEEN ON V54 INBND TO HRS. I ASKED CENTER IF THEY HAD SEEN THE TFC NEAR ME AND THEY HESITATED TO ANSWER ME. THE CTLR SAID SHE DIDN'T KNOW MY ALT AND DID NOT RPT THE TFC AFTER I COMPLAINED OF NO TFC WARNING. SHE COULD HAVE ASKED ME MY ALT AT ANY TIME. I COMPLAINED AGAIN AND ANOTHER CTLR CAME ON FREQ TO DISCUSS IT. HE SAID THE NEW RADAR WAS NOT AS GOOD AS THE OLD AND COULD NOT KEEP UP WITH MY CIRCUMNAV. I HAD NOT DONE THAT MUCH MANEUVERING. HE MUST HAVE BEEN HER SUPVR. THE OTHER PLT APPARENTLY SAW ME FIRST AND APPEARED TO BE TAKING EVASIVE ACTION; OTHERWISE WE WOULD HAVE PASSED WITHIN 200' VERT WITH ME DIRECTLY BELOW. CENTER COULD HAVE AVOIDED ALL THIS BY ANNOUNCING TFC.