NMAC BETWEEN GA-SMA AND GA-SMA.

Narrative

WHILE CONDUCTING AN INSTRUMENT CHK IN AN SMA OPERATING ON AN IFR FLT PLAN I NOTICED 2 ACFT AT OUR 12 O'CLOCK POS AFTER TURNING OUTBND ON THE PROC TURN. TIMING WAS STARTED PRIOR TO NOTICING THE 2 ACFT APPROX 1 MI AWAY AND COURSE WAS ADJUSTED TO REMAIN CLR. A TURN OF ABOUT 15 DEGS LEFT WAS REQUIRED FOR 10 SECS AND THEN A RETURN TO THE OUTBOUND 197 DEG HDG AT 3000' MSL. AT THIS TIME I LOOKED OVER MY RIGHT SHOULDER (I WAS IN THE RIGHT SEAT) AND SAW AN ACFT FOLLOWING US AT ABOUT 200' FROM A POS JUST BEHIND OUR RIGHT WING TIP AT THE SAME ALT. THE ACFT REMAINED THERE FOR ABOUT 20 SECS THEN MADE A STEEP DSNDING TURN TO THE RIGHT AND DEPARTED. THE 2 OCCUPANTS OF THE ACFT SEEMED TO BE LOOKING AT US AND VERY AWARE OF OUR PRESENCE. APCH CTL SAID THEY HAD NO CONTACT WITH ANY OF THE ACFT WE SAW AND THAT RADAR CONTACT IS NOT POSSIBLE DURING THE ENTIRE VOR A APCH AT 10G. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR DOES NOT THINK THE OTHER ACFT WAS TRYING TO FLY FORMATION AND HE DOESN'T KNOW WHERE HE CAME FROM; FELT OTHER PLT WAS PERHAPS TRYING TO GET HIS N NUMBER; BUT WHEN HE SAW HIM LOOKING SMA Y BROKE SHARPLY AWAY AND DOWN AND WAS NEVER SEEN AGAIN. SAID PROBABLE REASON APCH RADAR WAS NO LONGER PAINTING SMA X AND SMA Y IS BECAUSE TERRAIN IS HILLY IN AREA AND WERE PROBABLY BLOCKED BY HILL. IN THIS AREA ARE ONLY 2000' AGL.