Narrative:

Aircraft 1 departed atl en route to bna via cha. Aircraft departed atl en route to dma via cha. Both aircraft were climbed to FL270 and put on vectors east of cha to avoid inbound traffic to atl via cha rmg. Aircraft 1 was subsequently cleared direct cha and then descended to FL240. The pilot missed the descent clearance and I did not catch it. (The pilot also missed several other calls which had to be restated.) aircraft 2 was converging with aircraft 1 and sep was lost. At the time of the incident, the sector was moderately busy to traffic complex. I was conducting radar training and training was also being conducted on the associate sector. Flow control also had instituted zomit regardless of altitude restriction to the chicago airports (ord, mid). When the conflict between aircraft 1 and aircraft 2 was noticed, aircraft 2 was climbed to FL290 and turned to avoid aircraft 1. Aircraft 1 again was issued descent to FL240. Again, the pilot did not respond to the clearance. I called aircraft 1 again, and he finally responded. I then issued the clearance to FL240 again. Sep decreased to 4.65 mi and 400'. It was 19 seconds from the time I issued the second clearance to FL240 for aircraft 1 and the time the pilot responded on the third issuance. If the pilot had been listening as he should have been, this situation could have been avoided. Radio problems don't appear to be a factor as no one complained and other pilots were responding to calls. I realize pilots are sometimes distracted by other cockpit duties, but controllers are also distracted by other things. The unfortunate thing, though, is the pilot can get away with that, while the controller bears the brunt of the blame, and gets a letter in his file.

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Original NASA ASRS Text

Title: ARTCC RADAR CTLR FAILED TO PROVIDE STANDARD SEPARATION BETWEEN 2 ACFT UNDER HIS CONTROL.

Narrative: ACFT 1 DEPARTED ATL ENRTE TO BNA VIA CHA. ACFT DEPARTED ATL ENRTE TO DMA VIA CHA. BOTH ACFT WERE CLBED TO FL270 AND PUT ON VECTORS E OF CHA TO AVOID INBND TFC TO ATL VIA CHA RMG. ACFT 1 WAS SUBSEQUENTLY CLRED DIRECT CHA AND THEN DSNDED TO FL240. THE PLT MISSED THE DSNT CLRNC AND I DID NOT CATCH IT. (THE PLT ALSO MISSED SEVERAL OTHER CALLS WHICH HAD TO BE RESTATED.) ACFT 2 WAS CONVERGING WITH ACFT 1 AND SEP WAS LOST. AT THE TIME OF THE INCIDENT, THE SECTOR WAS MODERATELY BUSY TO TFC COMPLEX. I WAS CONDUCTING RADAR TRNING AND TRNING WAS ALSO BEING CONDUCTED ON THE ASSOCIATE SECTOR. FLOW CTL ALSO HAD INSTITUTED ZOMIT REGARDLESS OF ALT RESTRICTION TO THE CHICAGO ARPTS (ORD, MID). WHEN THE CONFLICT BTWN ACFT 1 AND ACFT 2 WAS NOTICED, ACFT 2 WAS CLBED TO FL290 AND TURNED TO AVOID ACFT 1. ACFT 1 AGAIN WAS ISSUED DSNT TO FL240. AGAIN, THE PLT DID NOT RESPOND TO THE CLRNC. I CALLED ACFT 1 AGAIN, AND HE FINALLY RESPONDED. I THEN ISSUED THE CLRNC TO FL240 AGAIN. SEP DECREASED TO 4.65 MI AND 400'. IT WAS 19 SECS FROM THE TIME I ISSUED THE SECOND CLRNC TO FL240 FOR ACFT 1 AND THE TIME THE PLT RESPONDED ON THE THIRD ISSUANCE. IF THE PLT HAD BEEN LISTENING AS HE SHOULD HAVE BEEN, THIS SITUATION COULD HAVE BEEN AVOIDED. RADIO PROBS DON'T APPEAR TO BE A FACTOR AS NO ONE COMPLAINED AND OTHER PLTS WERE RESPONDING TO CALLS. I REALIZE PLTS ARE SOMETIMES DISTRACTED BY OTHER COCKPIT DUTIES, BUT CTLRS ARE ALSO DISTRACTED BY OTHER THINGS. THE UNFORTUNATE THING, THOUGH, IS THE PLT CAN GET AWAY WITH THAT, WHILE THE CTLR BEARS THE BRUNT OF THE BLAME, AND GETS A LETTER IN HIS FILE.

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