PVT PLT FLEW INTO UNCTLED TFC PATTERN DURING AEROBATIC COMPETITION AND LANDED CAUSING SPECTATORS TO WORRY ABOUT A POSSIBLE COLLISION.

Narrative

I WAS RETURNING TO HOME BASE AFTER HAVING DEPARTED THE SAME MORNING ON A SHORT XCOUNTRY TRIP. AN AEROBATIC COMPETITION WAS IN PROGRESS. KNOWING THIS; I MONITORED THE CTAF STARTING 15 MI OUT. AT 10 MI NE I ANNOUNCED MY POS AND MY INTENTIONS TO LAND ON RWY 19 BY ENTERING THE L DOWNWIND LEG FROM W OF THE TOWN AND THE ARPT; XING OVER MIDFIELD. I CHOSE THIS APCH BECAUSE I KNOW THE AEROBATIC BOX WAS E OF THE RWY. I DIDN'T KNOW HOW FAR E. MY INTENTION WAS TO FLY A STANDARD PATTERN AT THE UNCTLED FIELD (NO UNICOM) WITH MIN DISRUPTION TO TFC. I MADE THE SAME COMPLETE ANNOUNCEMENT AT 4 MI N OF THE ARPT AFTER I HEARD A LNDG SMA AND A SMA (UNKNOWN WHETHER LNDG OR DEPARTING) ANNOUNCING ON THE CTAF. I AGAIN MADE THE SAME COMPLETE ANNOUNCEMENT 1 MI W OF MIDFIELD -- TO ENTER A L DOWNWIND LEG FOR RWY 19 AT PATTERN ALT -- 800 FT AGL. AT MIDFIELD; ONE OF 3 AGGRESSIVELY SCANNING PAX RPTED A SHADOW PASSING QUICKLY OVERHEAD. SOMEONE ON THE CTAF; PROBABLY A SPECTATOR ON THE GND (NO UNICOM); RPTED THE AEROBATIC COMPETITION IN PROGRESS AND SAID THEY WERE USING R TFC FOR RWY 19. I NOTICED THE AEROBATIC BOX MARKERS VERY CLOSE TO THE RWY AS I CROSSED MIDFIELD. I ASKED TO COMPLETE L TFC AS I WAS NEARING THE BASE TURN; AND NOTICED AN SMA WHO ANNOUNCED A R BASE FOR 19. NO PREVIOUS POS RPT WAS HEARD FROM THE SMA OR THE OBSERVER. I ANNOUNCED THAT I WOULD FOLLOW THE SMA ON FINAL FOR 19. AFTER WE TAXIED IN FOR FUEL; WE LEARNED THAT THE SMA HAD PASSED DIRECTLY OVER US AT AN UNKNOWN DISTANCE (THE PEOPLE ON THE GND WERE SOMEWHAT ALARMED). I HAD NOT CALLED FOR WX AND NOTAMS ON THE DAY DESCRIBED; AND WAS NOT AWARE OF R TFC FOR RWY 19. I HAD DEPARTED AND RETURNED TO THE ARPT THE DAY BEFORE DURING AEROBATIC ACTIVITY. ON THIS DAY I DID CALL WX AND WAS GIVEN NO NOTAMS UNTIL I PRESSED FOR THEM BECAUSE I WAS AWARE OF THE AEROBATIC ACTIVITY. I WAS GIVEN ONE THEN THAT DID NOT GIVE R TFC -- AS READ TO ME. I ALSO CALLED FOR NOTAMS BEFORE DEPARTING THE DAY AFTER THE FIRST DESCRIPTION; HAD TO ASK TWICE BEFORE GIVEN ONE -- NO R TURN MENTIONED. I WOULD LIKE THE AEROBATIC COMPETITION TO RETURN; I WOULD LIKE THE ARPT TO REMAIN OPEN TO TFC; AND I WOULD LIKE THE AIRSPACE TO BE SAFER. I CAN UNDERSTAND THAT A PLT PERFORMING MANEUVERS IN AEROBATIC COMPETITION WILL NOT BE LISTENING VERY INTENTLY TO THE CTAF. I WOULD STRONGLY SUGGEST AS AN ALTERNATIVE THAT THE CONTEST PERSONNEL HAVE SOMEONE ON THE GND MONITOR THE CTAF AND INFORM LCL AND COMPETING PLTS OF TFC AS NECESSARY FOR SAFETY. IN THIS TYPE OF SITUATION; VISUAL SCANNING SHOULD BE SUPPLEMENTED WITH POS RPTS FROM ALL PLTS OR CONTEST PERSONNEL AIDING THEM ON THE GND.