Narrative:

Working large scale, one holding sector 125 mi scale. Started my shift at XX45. Had an error at XY42. Problem working a lot of airspace. Scanning was limited. Extra people around could have helped. The conflict alert started with air carrier X and air carrier Y. Air carrier X was climbing to FL220 and air carrier Y was southeast at FL190. I saw air carrier X out of FL186 so I expedited the air carrier X down to FL180 and report reaching. I put a j-ring on air carrier X. I climbed air carrier Y to FL210 thinking I could get vertical separation. I then turned air carrier Y 30 degrees right and then issued traffic to air carrier X and turned him 40 degrees right. Right after this, I saw air carrier X mode C reading FL206 and thought there was no way to get vertical by descending him. I was back to air carrier Y and told him to maintain FL190 and report reaching. What I should have done differently: ask air carrier X rate of climb. Turn each aircraft left 40-50 degrees. Descend air carrier Y to 15000 ft. Vector air carrier X earlier for a short cut would have had lateral. Supplemental information from acn 257890: controller was climbing air carrier X to FL220 through air carrier Y at FL190. When it appeared there was separation between the 2 aircraft, controller tried to change plan and reverse his previous plan by climbing turboprop and descending turbojet. When the controller initially recognized that separation was not ensured, he should have stuck with the original plan and separation would not have been lost since air carrier X was climbing about 4000 FPM and would have been above the turboprop. The other option was to climb air carrier X to FL180, wait until he'd passed the turboprop, and then climbed to requested altitude.

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Original NASA ASRS Text

Title: ACR X CLB THROUGH OCCUPIED ALT HAD LTSS WITH ACR Y. SYS ERROR.

Narrative: WORKING LARGE SCALE, ONE HOLDING SECTOR 125 MI SCALE. STARTED MY SHIFT AT XX45. HAD AN ERROR AT XY42. PROB WORKING A LOT OF AIRSPACE. SCANNING WAS LIMITED. EXTRA PEOPLE AROUND COULD HAVE HELPED. THE CONFLICT ALERT STARTED WITH ACR X AND ACR Y. ACR X WAS CLBING TO FL220 AND ACR Y WAS SE AT FL190. I SAW ACR X OUT OF FL186 SO I EXPEDITED THE ACR X DOWN TO FL180 AND RPT REACHING. I PUT A J-RING ON ACR X. I CLBED ACR Y TO FL210 THINKING I COULD GET VERT SEPARATION. I THEN TURNED ACR Y 30 DEGS R AND THEN ISSUED TFC TO ACR X AND TURNED HIM 40 DEGS R. RIGHT AFTER THIS, I SAW ACR X MODE C READING FL206 AND THOUGHT THERE WAS NO WAY TO GET VERT BY DSNDING HIM. I WAS BACK TO ACR Y AND TOLD HIM TO MAINTAIN FL190 AND RPT REACHING. WHAT I SHOULD HAVE DONE DIFFERENTLY: ASK ACR X RATE OF CLB. TURN EACH ACFT L 40-50 DEGS. DSND ACR Y TO 15000 FT. VECTOR ACR X EARLIER FOR A SHORT CUT WOULD HAVE HAD LATERAL. SUPPLEMENTAL INFORMATION FROM ACN 257890: CTLR WAS CLBING ACR X TO FL220 THROUGH ACR Y AT FL190. WHEN IT APPEARED THERE WAS SEPARATION BTWN THE 2 ACFT, CTLR TRIED TO CHANGE PLAN AND REVERSE HIS PREVIOUS PLAN BY CLBING TURBOPROP AND DSNDING TURBOJET. WHEN THE CTLR INITIALLY RECOGNIZED THAT SEPARATION WAS NOT ENSURED, HE SHOULD HAVE STUCK WITH THE ORIGINAL PLAN AND SEPARATION WOULD NOT HAVE BEEN LOST SINCE ACR X WAS CLBING ABOUT 4000 FPM AND WOULD HAVE BEEN ABOVE THE TURBOPROP. THE OTHER OPTION WAS TO CLB ACR X TO FL180, WAIT UNTIL HE'D PASSED THE TURBOPROP, AND THEN CLBED TO REQUESTED ALT.

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.