Narrative:

2 aerobatic biplanes collided on the ground while participating in the united states aerobatic championships. Prior to taxiing to the far side of the taxiway, I checked for incoming traffic on the taxiway. I turned 90 degrees right and taxied straight down the west edge of the taxiway/ramp. I saw a plane (biplane) holding at the release point. I started an s-turn to the right. I had made 2 turns, looking both sides of aircraft and saw nothing. I had just started my third turn when I saw the small aircraft Y on the east side of taxiway going straight south. The pilot was looking slightly to his left, away from me. I saw the right wing coming at me, slightly to my right. I ducked down in my cockpit as far as the shoulder harness would allow. Following impact, my airplane was facing northeast. The small aircraft Y was facing southeast approximately 30 ft south of me. There was a temporary tower in operation. Aerobatic pilots were instructed in the briefing to monitor tower (126.6) when outgoing, after departure to go to 131.92 for clearance to the aerobatic box by the chief judge. I was not aware until the next day that the tower was not providing ground for the aerobatic pilots. No other pilot I talked with knew this. Observations/recommendations: forward visibility in small aircraft x-y type aircraft is restr, hence, s-turns are essential when taxiing. However, it is possible to get into sync with another s-turning small aircraft x-y and never see each other. It is recommended that s-turns not be made in a regular pattern so as to prevent this. Incoming and outgoing aircraft should not be on the same taxiway, particularly aerobatic aircraft. The role of the tower should be clarified as to ground control, control of which aircraft, and correct frequencys. The pilots should be made aware of the situation. A helmet is a must. My helmet was 'marked' heavily indicating my head 'banged' around inside the cockpit. Supplemental information from acn 252380: the situation was set up because both inbound and outbound traffic used the same taxiway, which I pointed out to the contest officials after the collision, and which was subsequently changed to more of a race track type pattern which should hopefully preclude a recurrence of this event.

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Original NASA ASRS Text

Title: 2 AEROBATIC ACFT SUFFER A GND COLLISION AS TAXIING TFC.

Narrative: 2 AEROBATIC BIPLANES COLLIDED ON THE GND WHILE PARTICIPATING IN THE UNITED STATES AEROBATIC CHAMPIONSHIPS. PRIOR TO TAXIING TO THE FAR SIDE OF THE TXWY, I CHKED FOR INCOMING TFC ON THE TXWY. I TURNED 90 DEGS R AND TAXIED STRAIGHT DOWN THE W EDGE OF THE TXWY/RAMP. I SAW A PLANE (BIPLANE) HOLDING AT THE RELEASE POINT. I STARTED AN S-TURN TO THE R. I HAD MADE 2 TURNS, LOOKING BOTH SIDES OF ACFT AND SAW NOTHING. I HAD JUST STARTED MY THIRD TURN WHEN I SAW THE SMA Y ON THE E SIDE OF TXWY GOING STRAIGHT S. THE PLT WAS LOOKING SLIGHTLY TO HIS L, AWAY FROM ME. I SAW THE R WING COMING AT ME, SLIGHTLY TO MY R. I DUCKED DOWN IN MY COCKPIT AS FAR AS THE SHOULDER HARNESS WOULD ALLOW. FOLLOWING IMPACT, MY AIRPLANE WAS FACING NE. THE SMA Y WAS FACING SE APPROX 30 FT S OF ME. THERE WAS A TEMPORARY TWR IN OP. AEROBATIC PLTS WERE INSTRUCTED IN THE BRIEFING TO MONITOR TWR (126.6) WHEN OUTGOING, AFTER DEP TO GO TO 131.92 FOR CLRNC TO THE AEROBATIC BOX BY THE CHIEF JUDGE. I WAS NOT AWARE UNTIL THE NEXT DAY THAT THE TWR WAS NOT PROVIDING GND FOR THE AEROBATIC PLTS. NO OTHER PLT I TALKED WITH KNEW THIS. OBSERVATIONS/RECOMMENDATIONS: FORWARD VISIBILITY IN SMA X-Y TYPE ACFT IS RESTR, HENCE, S-TURNS ARE ESSENTIAL WHEN TAXIING. HOWEVER, IT IS POSSIBLE TO GET INTO SYNC WITH ANOTHER S-TURNING SMA X-Y AND NEVER SEE EACH OTHER. IT IS RECOMMENDED THAT S-TURNS NOT BE MADE IN A REGULAR PATTERN SO AS TO PREVENT THIS. INCOMING AND OUTGOING ACFT SHOULD NOT BE ON THE SAME TXWY, PARTICULARLY AEROBATIC ACFT. THE ROLE OF THE TWR SHOULD BE CLARIFIED AS TO GND CTL, CTL OF WHICH ACFT, AND CORRECT FREQS. THE PLTS SHOULD BE MADE AWARE OF THE SIT. A HELMET IS A MUST. MY HELMET WAS 'MARKED' HEAVILY INDICATING MY HEAD 'BANGED' AROUND INSIDE THE COCKPIT. SUPPLEMENTAL INFORMATION FROM ACN 252380: THE SIT WAS SET UP BECAUSE BOTH INBOUND AND OUTBOUND TFC USED THE SAME TXWY, WHICH I POINTED OUT TO THE CONTEST OFFICIALS AFTER THE COLLISION, AND WHICH WAS SUBSEQUENTLY CHANGED TO MORE OF A RACE TRACK TYPE PATTERN WHICH SHOULD HOPEFULLY PRECLUDE A RECURRENCE OF THIS EVENT.

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