Narrative:

I was level at 2300 ft. Approximately 5 mi ene of st pete when I contacted the tower. St pete tower instructed me to enter a right downwind for runway 35R. The tower informed me that there was a coast guard helicopter departing runway 4. When I confirmed sight of the traffic, the tower informed me that the traffic would remain east of the runway and cleared me to land. I watched the coast guard helicopter proceed on the upwind path for runway 4 and I entered the right downwind for the runway 35R. After watching the coast guard traffic for a few seconds, I saw him suddenly reverse direction, and in a matter of a few seconds more, cross in front of my aircraft and above me, missing me by approximately 300 ft vertically and 300 to 400 ft horizontally. With virtually no time to react, I managed to descend slightly and turn to the left so as to pass farther behind the helicopter and farther below him. I expected there to be severe downwash from the helicopter, but there was none. It is my opinion that the helicopter suddenly reversed his direction of travel or at least extremely shortened his pattern and ignored tower instructions to remain east of the runway. Also, st pete tower should not have cleared me to enter the air traffic area or should not have allowed the coast guard to remain east of the runway. To me, it would have been much easier to have had the helicopter extend his upwind for spacing. At the time of the near miss, I was at or near pattern altitude and approximately midfield on the downwind.

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Original NASA ASRS Text

Title: SMA PLT HAS NMAC WITH HELI IN TFC PATTERN.

Narrative: I WAS LEVEL AT 2300 FT. APPROX 5 MI ENE OF ST PETE WHEN I CONTACTED THE TWR. ST PETE TWR INSTRUCTED ME TO ENTER A R DOWNWIND FOR RWY 35R. THE TWR INFORMED ME THAT THERE WAS A COAST GUARD HELI DEPARTING RWY 4. WHEN I CONFIRMED SIGHT OF THE TFC, THE TWR INFORMED ME THAT THE TFC WOULD REMAIN E OF THE RWY AND CLRED ME TO LAND. I WATCHED THE COAST GUARD HELI PROCEED ON THE UPWIND PATH FOR RWY 4 AND I ENTERED THE R DOWNWIND FOR THE RWY 35R. AFTER WATCHING THE COAST GUARD TFC FOR A FEW SECONDS, I SAW HIM SUDDENLY REVERSE DIRECTION, AND IN A MATTER OF A FEW SECONDS MORE, CROSS IN FRONT OF MY ACFT AND ABOVE ME, MISSING ME BY APPROX 300 FT VERTICALLY AND 300 TO 400 FT HORIZLY. WITH VIRTUALLY NO TIME TO REACT, I MANAGED TO DSND SLIGHTLY AND TURN TO THE L SO AS TO PASS FARTHER BEHIND THE HELI AND FARTHER BELOW HIM. I EXPECTED THERE TO BE SEVERE DOWNWASH FROM THE HELI, BUT THERE WAS NONE. IT IS MY OPINION THAT THE HELI SUDDENLY REVERSED HIS DIRECTION OF TRAVEL OR AT LEAST EXTREMELY SHORTENED HIS PATTERN AND IGNORED TWR INSTRUCTIONS TO REMAIN E OF THE RWY. ALSO, ST PETE TWR SHOULD NOT HAVE CLRED ME TO ENTER THE ATA OR SHOULD NOT HAVE ALLOWED THE COAST GUARD TO REMAIN E OF THE RWY. TO ME, IT WOULD HAVE BEEN MUCH EASIER TO HAVE HAD THE HELI EXTEND HIS UPWIND FOR SPACING. AT THE TIME OF THE NEAR MISS, I WAS AT OR NEAR PATTERN ALT AND APPROX MIDFIELD ON THE DOWNWIND.

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.