Narrative:

As an fpl controller at ind ARTCC I was working the falmouth hi (FL240 and up) for the midnight shift. The latitude confines of this sector extend from 70 NM east and northeast of nashville to the newcombe VORTAC from 30 NM north of knoxville to cincinnati. During the time of this incident a lot of thunderstorm activity was present in the area around lexington. As the various cargo hauling aircraft began their post sorting flight the sector became busy with the number of aircraft and the amount of in-flight deviations around the WX. The 2 aircraft involved were as follows: aircraft X was en route from memphis to pittsburg at FL330. Aircraft Y was en route from ft wayne to atlanta at FL330. During this time I was allowing a manual controller (deviation) to work the frequencys to gain radar experience under my supervision. Aircraft X had requested and received permission to deviate around WX and proceed on course when he was able. We realized the problems this might cause for flts southbound at or requesting FL330. When we received the handoff on aircraft Y the aircraft was already east of course from deviations he took in the previous sector. We realized the possible confliction between these 2 aircraft and discussed possible solutions. We instructed aircraft Y to turn 15 degrees right of his present course to go at least 5 NM behind aircraft X. As our attention was diverted elsewhere (sector was now busy) we failed to see X turn back to the left, apparently finished deviating. (This was an awareness problem on my part. X should have been instructed not to turn left.) when aircraft X's turn was noticed I took over the frequencys and instructed X to turn back right to a heading of 090 degrees. He did not acknowledge this call so I repeated the clearance. The second clearance was blocked by another aircraft talking at the same time. The third clearance was acknowledged by X. I then instructed Y to fly heading 270 degrees. This was immediately acknowledged. These clrncs came a little late to maintain 5 NM latitude sep. The closest point was 4.09 NM. After the aircraft passed they were both cleared 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, pilot's awareness and attention this time of day (they don't seem to listen), WX and frequency congestion, and loose type operation of this facility on midnight shifts.

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Original NASA ASRS Text

Title: 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.

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.