Narrative:

Denver ARTCC sector 9 had training on both radar and interphone positions. I was instructing on the radar position. My trnee had been working a busy rush period for approximately 1 1/2 hours with up to 22 aircraft in the sector at one time. By this time the complexity had relaxed, with approximately 12 aircraft in the sector. At XXXX, air carrier Y widebody transport checked on frequency at a point west of hayes center at FL370 direct to O'neil. At this time air carrier X was 45 NM east of north platte direct to den at FL350. At XXXX air carrier X requested climb to FL390. My student climbed air carrier X to FL390 with a restriction to be level by XXXX, to miss air carrier Z 70 NM west of lbf, eastbound at FL370. My attention was turned to air carrier Z and other aircraft in that vicinity, my student and I did not coordinate air carrier Y into the problem. At XXXX C/a was activated between air carrier and air carrier Y (both at FL370). I took communication control and issued an immediate right turn to 360 degrees for air carrier X, which he acknowledged. Air carrier Y was issued an immediate right turn to 110 degrees, which he acknowledged. Aircraft passed with 1000' vertical and 4.6 NM latitude sep. Air carrier Y was descended to FL350 in order to try to prevent the system error. Air carrier X response was immediate and a sharp turn was observed. Air carrier Y turn was very flat and in fact he never left FL370 for FL350 when he was reclred to O'neil and to maintain FL370. This system error seems to be a complete failure on my part to see air carrier Y as a factor to air carrier X.

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Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION BETWEEN ACR X AND Y. SYSTEM ERROR.

Narrative: DENVER ARTCC SECTOR 9 HAD TRNING ON BOTH RADAR AND INTERPHONE POSITIONS. I WAS INSTRUCTING ON THE RADAR POS. MY TRNEE HAD BEEN WORKING A BUSY RUSH PERIOD FOR APPROX 1 1/2 HRS WITH UP TO 22 ACFT IN THE SECTOR AT ONE TIME. BY THIS TIME THE COMPLEXITY HAD RELAXED, WITH APPROX 12 ACFT IN THE SECTOR. AT XXXX, ACR Y WDB CHKED ON FREQ AT A POINT W OF HAYES CENTER AT FL370 DIRECT TO O'NEIL. AT THIS TIME ACR X WAS 45 NM E OF NORTH PLATTE DIRECT TO DEN AT FL350. AT XXXX ACR X REQUESTED CLB TO FL390. MY STUDENT CLBED ACR X TO FL390 WITH A RESTRICTION TO BE LEVEL BY XXXX, TO MISS ACR Z 70 NM W OF LBF, EBND AT FL370. MY ATTN WAS TURNED TO ACR Z AND OTHER ACFT IN THAT VICINITY, MY STUDENT AND I DID NOT COORDINATE ACR Y INTO THE PROB. AT XXXX C/A WAS ACTIVATED BTWN ACR AND ACR Y (BOTH AT FL370). I TOOK COM CTL AND ISSUED AN IMMEDIATE RIGHT TURN TO 360 DEGS FOR ACR X, WHICH HE ACKNOWLEDGED. ACR Y WAS ISSUED AN IMMEDIATE RIGHT TURN TO 110 DEGS, WHICH HE ACKNOWLEDGED. ACFT PASSED WITH 1000' VERT AND 4.6 NM LAT SEP. ACR Y WAS DSNDED TO FL350 IN ORDER TO TRY TO PREVENT THE SYS ERROR. ACR X RESPONSE WAS IMMEDIATE AND A SHARP TURN WAS OBSERVED. ACR Y TURN WAS VERY FLAT AND IN FACT HE NEVER LEFT FL370 FOR FL350 WHEN HE WAS RECLRED TO O'NEIL AND TO MAINTAIN FL370. THIS SYS ERROR SEEMS TO BE A COMPLETE FAILURE ON MY PART TO SEE ACR Y AS A FACTOR TO ACR X.

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.