Narrative:

On flight from columbia, sc (cae) to williamsburg, va (jgg), I was northeast bound on V-155 approximately 10 northeast of rdu VOR. I was level at 9000' when an small aircraft Y passed off my right wing, opposite direction. It was passed me by the time any evasive action action could have been taken. It appeared to be level at 9000' and was swbnd, appearing to be following V-155. I asked raleigh approach about the traffic (I was IFR, talking to raleigh) and they did not see it on their radar, nor were they handling it, IFR or VFR. Also talked to ZDC and none of their sectors had handled it either. Apparently, the small aircraft Y was VFR on the airway at the wrong altitude. Could have been tragic!

Google
 

Original NASA ASRS Text

Title: CLOSE PROX GA SMA NORTHEASTBOUND ON V155, GA SMA SOUTHWESTBOUND ON V155 AT WRONG ALT.

Narrative: ON FLT FROM COLUMBIA, SC (CAE) TO WILLIAMSBURG, VA (JGG), I WAS NE BOUND ON V-155 APPROX 10 NE OF RDU VOR. I WAS LEVEL AT 9000' WHEN AN SMA Y PASSED OFF MY RIGHT WING, OPPOSITE DIRECTION. IT WAS PASSED ME BY THE TIME ANY EVASIVE ACTION ACTION COULD HAVE BEEN TAKEN. IT APPEARED TO BE LEVEL AT 9000' AND WAS SWBND, APPEARING TO BE FOLLOWING V-155. I ASKED RALEIGH APCH ABOUT THE TFC (I WAS IFR, TALKING TO RALEIGH) AND THEY DID NOT SEE IT ON THEIR RADAR, NOR WERE THEY HANDLING IT, IFR OR VFR. ALSO TALKED TO ZDC AND NONE OF THEIR SECTORS HAD HANDLED IT EITHER. APPARENTLY, THE SMA Y WAS VFR ON THE AIRWAY AT THE WRONG ALT. COULD HAVE BEEN TRAGIC!

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