Narrative:

I was on a heading of 005 degrees, level at 7500 ft MSL, and in contact with travis approach for VFR flight following when I observed a large twin rotor military helicopter transport at my 11 O'clock position, same altitude, and approximately 4-5 NM. It appeared to be on a parallel course and that I would be overtaking the helicopter and passing a mi to the right. Approximately a min after sighting the helicopter, travis approach called out cessna traffic sebound, 7500 ft, 12-1 O'clock position, and 5 mi. I acknowledged visual contact to travis, and made a slight course correction towards the east as the cessna moved to my 2 O'clock position. My thinking was to pass behind the cessna providing a diverging course relative to the military helicopter. When I looked left to verify the position of the helicopter it was suddenly at my 10 O'clock position, less than 500 ft and approximately 50 ft above and was on a heading of approximately 140 degrees. I immediately descended passing approximately 250-300 ft below and 50-100 ft in front of the helicopter. The helicopter contacted travis approach reporting a near miss and asked if the controller had called out the traffic to him. The controller was non committal in his response saying that he had called out various unidented VFR targets several mins ago. I believe that I heard that transmission, but I did not hear any traffic callout that I would have taken to be my aircraft, nor did I receive an advisory on the helicopter which was a far bigger threat than the cessna traffic. The situation occurred because of my visual perception of parallel course versus collision. Use of landing light by the helicopter would have indicated that I was viewing the nose of the aircraft rather than the tail.

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Original NASA ASRS Text

Title: SMA HAS NMAC WITH MIL HELI.

Narrative: I WAS ON A HDG OF 005 DEGS, LEVEL AT 7500 FT MSL, AND IN CONTACT WITH TRAVIS APCH FOR VFR FLT FOLLOWING WHEN I OBSERVED A LARGE TWIN ROTOR MIL HELI TRANSPORT AT MY 11 O'CLOCK POS, SAME ALT, AND APPROX 4-5 NM. IT APPEARED TO BE ON A PARALLEL COURSE AND THAT I WOULD BE OVERTAKING THE HELI AND PASSING A MI TO THE R. APPROX A MIN AFTER SIGHTING THE HELI, TRAVIS APCH CALLED OUT CESSNA TFC SEBOUND, 7500 FT, 12-1 O'CLOCK POS, AND 5 MI. I ACKNOWLEDGED VISUAL CONTACT TO TRAVIS, AND MADE A SLIGHT COURSE CORRECTION TOWARDS THE E AS THE CESSNA MOVED TO MY 2 O'CLOCK POS. MY THINKING WAS TO PASS BEHIND THE CESSNA PROVIDING A DIVERGING COURSE RELATIVE TO THE MIL HELI. WHEN I LOOKED L TO VERIFY THE POS OF THE HELI IT WAS SUDDENLY AT MY 10 O'CLOCK POS, LESS THAN 500 FT AND APPROX 50 FT ABOVE AND WAS ON A HDG OF APPROX 140 DEGS. I IMMEDIATELY DSNDED PASSING APPROX 250-300 FT BELOW AND 50-100 FT IN FRONT OF THE HELI. THE HELI CONTACTED TRAVIS APCH RPTING A NEAR MISS AND ASKED IF THE CTLR HAD CALLED OUT THE TFC TO HIM. THE CTLR WAS NON COMMITTAL IN HIS RESPONSE SAYING THAT HE HAD CALLED OUT VARIOUS UNIDENTED VFR TARGETS SEVERAL MINS AGO. I BELIEVE THAT I HEARD THAT XMISSION, BUT I DID NOT HEAR ANY TFC CALLOUT THAT I WOULD HAVE TAKEN TO BE MY ACFT, NOR DID I RECEIVE AN ADVISORY ON THE HELI WHICH WAS A FAR BIGGER THREAT THAN THE CESSNA TFC. THE SIT OCCURRED BECAUSE OF MY VISUAL PERCEPTION OF PARALLEL COURSE VERSUS COLLISION. USE OF LNDG LIGHT BY THE HELI WOULD HAVE INDICATED THAT I WAS VIEWING THE NOSE OF THE ACFT RATHER THAN THE TAIL.

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.