PA28 PLT OPERATING VFR ON A VICTOR AIRWAY HAS CLOSE ENCOUNTER WITH AN AEROBATIC ACFT PRACTICING LOOPS.

Narrative

I WAS CRUISING AT 3000 FT WBOUND ON V20 DIRECTLY OVER THE LE GROS ARPT (3R2). I WAS OPERATING UNDER VFR; AND WAS RECEIVING FLT FOLLOWING FROM LAFAYETTE APCH CTL. ALL OF A SUDDEN I SEE A PLANE AT MY ALT COMING TOWARDS ME. IT WAS CLOSE; AND I WAS SURPRISED I HADN'T SEEN IT EARLIER. I NOTICED THAT THE ONCOMING PLANE WAS UPSIDE DOWN; AND WAS TRAILING SMOKE. I IMMEDIATELY BANKED L TO AVOID THE PLANE. AS I PASSED; I LOOKED BACK AND REALIZED THE PLANE WAS DOING A LOOP. MY INITIAL IMPRESSION WAS THAT THE OTHER ACFT WAS A BIPLANE; BUT I CAN'T BE SURE OF THAT. I CALLED ATC (LAFAYETTE APCH) TO ASK IF THEY HAD SEEN HIM ON RADAR; AND THE CTLR FIRST SAID HE DID NOT SEE HIM ON RADAR; THEN THE CTLR SAID THAT HE DID HAVE A PRIMARY TARGET JUST NE OF MY POS. I TOLD HIM THAT THE OTHER PLANE HAD JUST DONE A LOOP THAT TOPPED OUT AT 3000 FT RIGHT IN THE MIDDLE OF AN AIRWAY. I REJOINED THE AIRWAY AND CONTINUED MY FLT. THE CAUSE OF THIS PROB WAS THAT A PLT CHOSE TO DO AN AEROBATIC MANEUVER ALONG A FEDERAL AIRWAY WHERE IT IS OBVIOUS THAT AIR TFC IS LIKELY TO BE. THE FACT THAT THE MANEUVER WAS A LOOP MADE THE SITUATION EVEN MORE DANGEROUS; BECAUSE THE RAPID CLB MAKES IT HARD FOR ATC TO GIVE TIMELY ALERTS TO NEARBY ACFT. TO PREVENT A RECURRENCE OF THIS TYPE OF EVENT; AN INVESTIGATION SHOULD BE MADE TO FIND THIS PLT AND DISCIPLINE HIM.