LESS THAN STANDARD SEPARATION BETWEEN 2 SUPPLEMENTAL ACR CARGO FLTS. OPERATIONAL ERROR.

Narrative

AS AN FPL CTLR AT IND ARTCC I WAS WORKING THE FALMOUTH HI (FL240 AND UP) FOR THE MIDNIGHT SHIFT. THE LAT CONFINES OF THIS SECTOR EXTEND FROM 70 NM E AND NE OF NASHVILLE TO THE NEWCOMBE VORTAC FROM 30 NM N OF KNOXVILLE TO CINCINNATI. DURING THE TIME OF THIS INCIDENT A LOT OF TSTM ACTIVITY WAS PRESENT IN THE AREA AROUND LEXINGTON. AS THE VARIOUS CARGO HAULING ACFT BEGAN THEIR POST SORTING FLT THE SECTOR BECAME BUSY WITH THE NUMBER OF ACFT AND THE AMOUNT OF INFLT DEVIATIONS AROUND THE WX. THE 2 ACFT INVOLVED WERE AS FOLLOWS: ACFT X WAS ENRTE FROM MEMPHIS TO PITTSBURG AT FL330. ACFT Y WAS ENRTE FROM FT WAYNE TO ATLANTA AT FL330. DURING THIS TIME I WAS ALLOWING A MANUAL CTLR (DEV) TO WORK THE FREQS TO GAIN RADAR EXPERIENCE UNDER MY SUPERVISION. ACFT X HAD REQUESTED AND RECEIVED PERMISSION TO DEVIATE AROUND WX AND PROCEED ON COURSE WHEN HE WAS ABLE. WE REALIZED THE PROBS THIS MIGHT CAUSE FOR FLTS SBND AT OR REQUESTING FL330. WHEN WE RECEIVED THE HDOF ON ACFT Y THE ACFT WAS ALREADY E OF COURSE FROM DEVIATIONS HE TOOK IN THE PREVIOUS SECTOR. WE REALIZED THE POSSIBLE CONFLICTION BTWN THESE 2 ACFT AND DISCUSSED POSSIBLE SOLUTIONS. WE INSTRUCTED ACFT Y TO TURN 15 DEGS RIGHT OF HIS PRESENT COURSE TO GO AT LEAST 5 NM BEHIND ACFT X. AS OUR ATTN WAS DIVERTED ELSEWHERE (SECTOR WAS NOW BUSY) WE FAILED TO SEE X TURN BACK TO THE LEFT; APPARENTLY FINISHED DEVIATING. (THIS WAS AN AWARENESS PROB ON MY PART. X SHOULD HAVE BEEN INSTRUCTED NOT TO TURN LEFT.) WHEN ACFT X'S TURN WAS NOTICED I TOOK OVER THE FREQS AND INSTRUCTED X TO TURN BACK RIGHT TO A HDG OF 090 DEGS. HE DID NOT ACKNOWLEDGE THIS CALL SO I REPEATED THE CLRNC. THE SECOND CLRNC WAS BLOCKED BY ANOTHER ACFT TALKING AT THE SAME TIME. THE THIRD CLRNC WAS ACKNOWLEDGED BY X. I THEN INSTRUCTED Y TO FLY HDG 270 DEGS. THIS WAS IMMEDIATELY ACKNOWLEDGED. THESE CLRNCS CAME A LITTLE LATE TO MAINTAIN 5 NM LAT SEP. THE CLOSEST POINT WAS 4.09 NM. AFTER THE ACFT PASSED THEY WERE BOTH CLRED ON COURSE. CAUSATIVE FACTORS AS I SEE THEM: MY AWARENESS WAS NOT AS SHARP AS IT SHOULD BE DUE TO TIME OF DAY AND SCHEDULE; ALSO SOME JOB BURNOUT; PLT'S AWARENESS AND ATTN THIS TIME OF DAY (THEY DON'T SEEM TO LISTEN); WX AND FREQ CONGESTION; AND LOOSE TYPE OPERATION OF THIS FAC ON MIDNIGHT SHIFTS.