Narrative:

Near miss occurred in class east airspace while I was in cruising flight at 1800 ft on an easterly heading (approximately 100 degrees) over the rappahannock river about 3 mi east of shannon airport (ezf), fredericksburg, va (near the 200 degree radial of brooke VOR about 7 mi below the station). I suddenly spotted a military helicopter on my left at a horizontal distance of about 2000 ft about to intersect my course at close to a 90-100 degree angle. Vertical separation was obviously sufficient to avoid collision, but disturbingly close and difficult to judge accurately, possibly in the vicinity of 200 ft. I could detect no evasive action by the helicopter and immediately began a full power climb to increase the vertical separation. The helicopter quickly passed under the rear of my airplane. I then observed a second helicopter in trail, but sufficiently far back that he would pass behind me at a safe distance. Looking over my right shoulder I determined both had passed beyond my airplane and appeared to be continuing on course. Suddenly, the second helicopter initiated a left turn and took an interception heading toward me. After overtaking me the pilot slowed to my speed and held a parallel course about 150 ft off my right side and to the immediate rear of my airplane. I monitored 121.5, anticipating a call, but none came. After 1-2 mins he abruptly terminated the interception with a right turn back toward his original heading. I can only presume he was attempting to identify my north number (perhaps not possible because of 3 inch numbers on this older cessna). I was maintaining a vigilant scan so was shocked by the unexpected encounter. Apparently, the pilot also failed to see me in a timely manner. This seems to be simply an unfortunate situation in which the human eye momentarily failed both of us.

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Original NASA ASRS Text

Title: C152 PLT RPTS NMAC WITH FLT OF 2 MIL HELI'S IN THE VICINITY OF HILL MOA.

Narrative: NEAR MISS OCCURRED IN CLASS E AIRSPACE WHILE I WAS IN CRUISING FLT AT 1800 FT ON AN EASTERLY HDG (APPROX 100 DEGS) OVER THE RAPPAHANNOCK RIVER ABOUT 3 MI E OF SHANNON ARPT (EZF), FREDERICKSBURG, VA (NEAR THE 200 DEG RADIAL OF BROOKE VOR ABOUT 7 MI BELOW THE STATION). I SUDDENLY SPOTTED A MIL HELI ON MY L AT A HORIZ DISTANCE OF ABOUT 2000 FT ABOUT TO INTERSECT MY COURSE AT CLOSE TO A 90-100 DEG ANGLE. VERT SEPARATION WAS OBVIOUSLY SUFFICIENT TO AVOID COLLISION, BUT DISTURBINGLY CLOSE AND DIFFICULT TO JUDGE ACCURATELY, POSSIBLY IN THE VICINITY OF 200 FT. I COULD DETECT NO EVASIVE ACTION BY THE HELI AND IMMEDIATELY BEGAN A FULL PWR CLB TO INCREASE THE VERT SEPARATION. THE HELI QUICKLY PASSED UNDER THE REAR OF MY AIRPLANE. I THEN OBSERVED A SECOND HELI IN TRAIL, BUT SUFFICIENTLY FAR BACK THAT HE WOULD PASS BEHIND ME AT A SAFE DISTANCE. LOOKING OVER MY R SHOULDER I DETERMINED BOTH HAD PASSED BEYOND MY AIRPLANE AND APPEARED TO BE CONTINUING ON COURSE. SUDDENLY, THE SECOND HELI INITIATED A L TURN AND TOOK AN INTERCEPTION HDG TOWARD ME. AFTER OVERTAKING ME THE PLT SLOWED TO MY SPD AND HELD A PARALLEL COURSE ABOUT 150 FT OFF MY R SIDE AND TO THE IMMEDIATE REAR OF MY AIRPLANE. I MONITORED 121.5, ANTICIPATING A CALL, BUT NONE CAME. AFTER 1-2 MINS HE ABRUPTLY TERMINATED THE INTERCEPTION WITH A R TURN BACK TOWARD HIS ORIGINAL HDG. I CAN ONLY PRESUME HE WAS ATTEMPTING TO IDENT MY N NUMBER (PERHAPS NOT POSSIBLE BECAUSE OF 3 INCH NUMBERS ON THIS OLDER CESSNA). I WAS MAINTAINING A VIGILANT SCAN SO WAS SHOCKED BY THE UNEXPECTED ENCOUNTER. APPARENTLY, THE PLT ALSO FAILED TO SEE ME IN A TIMELY MANNER. THIS SEEMS TO BE SIMPLY AN UNFORTUNATE SIT IN WHICH THE HUMAN EYE MOMENTARILY FAILED BOTH OF US.

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.