Narrative:

My aircraft was the #2 aircraft in a flight of 2. We were in loose trail formation maneuvering in the area described above between 2000-2500 ft MSL. We were on air-air frequency and monitoring unicom 122.8. The lead aircraft was approximately 500 ft ahead of my aircraft in a shallow left bank/turn. In my peripheral vision, I noticed the C172 behind and off the left wing of the lead aircraft. If both aircraft had continued, in less than 2 seconds a collision would have occurred. On air-air frequency, I shouted 'break right, turn right now!' the aircraft came within 100 ft with neither aircraft seeing each other. The C172 never changed course or maneuvered. During the avoidance maneuver (climbing right turn) we may have transiently entered class B airspace approximately 3200 ft for a few seconds. With the aircraft in sight, the flight made 2 wide 360 degree turns well behind (over 1000 ft) the C172 to identify the n-number. During the 2 360 degree turns, no close approximation of aircraft occurred and the C172 was in sight constantly. The C172 was flying a practice approach to awm.

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Original NASA ASRS Text

Title: PLT OF AEROBATIC SMA WARNS HIS FORMATION FLYING PARTNER OF IMPENDING NMAC WITH PASSING C172. EVASIVE ACTION ENSUES.

Narrative: MY ACFT WAS THE #2 ACFT IN A FLT OF 2. WE WERE IN LOOSE TRAIL FORMATION MANEUVERING IN THE AREA DESCRIBED ABOVE BTWN 2000-2500 FT MSL. WE WERE ON AIR-AIR FREQ AND MONITORING UNICOM 122.8. THE LEAD ACFT WAS APPROX 500 FT AHEAD OF MY ACFT IN A SHALLOW L BANK/TURN. IN MY PERIPHERAL VISION, I NOTICED THE C172 BEHIND AND OFF THE L WING OF THE LEAD ACFT. IF BOTH ACFT HAD CONTINUED, IN LESS THAN 2 SECONDS A COLLISION WOULD HAVE OCCURRED. ON AIR-AIR FREQ, I SHOUTED 'BREAK R, TURN R NOW!' THE ACFT CAME WITHIN 100 FT WITH NEITHER ACFT SEEING EACH OTHER. THE C172 NEVER CHANGED COURSE OR MANEUVERED. DURING THE AVOIDANCE MANEUVER (CLBING R TURN) WE MAY HAVE TRANSIENTLY ENTERED CLASS B AIRSPACE APPROX 3200 FT FOR A FEW SECONDS. WITH THE ACFT IN SIGHT, THE FLT MADE 2 WIDE 360 DEG TURNS WELL BEHIND (OVER 1000 FT) THE C172 TO IDENT THE N-NUMBER. DURING THE 2 360 DEG TURNS, NO CLOSE APPROXIMATION OF ACFT OCCURRED AND THE C172 WAS IN SIGHT CONSTANTLY. THE C172 WAS FLYING A PRACTICE APCH TO AWM.

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.