ACR X POTENTIAL LTSS FROM ACR Y. POTENTIAL SYS ERROR. SEE CALLBACK.

Narrative

WHILE WORKING THE CARLTON SECTOR (AT OR BELOW FL230); A MODERATELY BUSY TFC SITUATION DEVELOPED. DURING THIS PERIOD ACR X FL240 CHKED ON THE FREQ. SHORTLY AFTER; ACR Y FL220; RPTED ON THE FREQ. APPROX 10 NM EXISTED BTWN THESE 2 ACFT; IN TRAIL; AT THIS TIME WITH LEAD ACFT ACR X SHOWING GND SPD 540 KTS. ACR Y IN TRAIL SHOWED GND SPD 470 KTS. NO SPD ADJUSTMENT APPEARED NECESSARY. BOTH ACFT WERE ISSUED DSCNT TO 12000 FT. SUBSEQUENTLY THE GND SPDS CHANGED SIGNIFICANTLY DUE TO WIND VARIATIONS AND/OR PLT OPERATIONAL PROC. WHEN BOTH ACFT WERE BELOW FL200 DSNDING; THE LEAD ACFT HAD REDUCED GND SPD TO 380 KTS AND FOLLOWING ACFT WAS AT GND SPD 420 KTS; A 40 KT OVERTAKE. SEVERAL INSTRUCTIONS WERE ISSUED TO PREVENT A LOSS OF SEPARATION. FOLLOWING ACR Y REDUCED TO 250 KTS IAS; FOLLOWING ACR Y ISSUED L TURN TO HDG 260; AND FOLLOWING ACR Y LEVELED OFF AT PRESENT ALT (FL195). NO ACTION HAD BEEN TAKEN SOONER DUE TO NORMAL PROC TO OBSERVE PRESENT GND SPDS AND IN TRAIL (LONGITUDINAL) SEPARATION. WHEN THESE 2 OBSERVATIONS INDICATE CONSTANT OR INCREASING SEPARATION; VERT SEPARATION IS NO LONGER NECESSARY; THUS; BOTH ACFT WERE GIVEN DSCNT CLRNCS TO 12000 FT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO. THE RPTR STATED THE INCIDENT WAS INVESTIGATED AS A SYS ERROR BECAUSE CONFLICT ALERT ACTIVATED AND 1 HIT FROM THE RADAR PLOT INDICATED 4.8 MI SEPARATION. THE RPTR FURTHER STATED FACILITY MGMNT INVESTIGATOR SHOWED THE RADAR PLT AS IN ERROR AND THE INCIDENT HAS BEEN DOWNGRADED TO A NON- EVENT. RADAR SEPARATION WAS MAINTAINED.