Narrative:

Air carrier Y was wbound on J80 at FL310. Air carrier X was eastbound at FL330. I descended air carrier X to FL240 when the aircraft were 40-50 mi apart. About 45 seconds later, I did not think air carrier X was descending very quickly, so I told the aircraft to expedite through FL290 for traffic. Air carrier X responded and acknowledged to hurry through FL290. I then observed air carrier X to be descending at 1800-2000 FPM which would have easily ensured separation. I told the aircraft I would need him out of FL290 in a min and a half for traffic, but was not acknowledged. When air carrier X was at roughly FL300, I called traffic at 12 O'clock, 15 miles, opposite direction, FL310. I then told air carrier X I would need a report out of FL290 in about 10 seconds. About 5 seconds later, air carrier X gave the first verbal indication he would have some difficulty doing this, and asked that he or the other aircraft be given a vector. I turned air carrier X 50 degree right and air carrier Y 30 degree right and told air carrier X to report FL290. Air carrier X replied with 'coming up on 290'. Aedp activated. Air carrier X then replied to my numerous altitude requests with reports of FL296, and then 20 seconds later FL295. The two aircraft closest point was 1.2 mi and 1500'. Supplemental information from acn 136223. My understanding is that it would have been a pilot deviation if the 'right' controller had told the pilot the center time when telling him he needed him out of FL290 in a min and a half or assigned the pilot a rate of descent.

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Original NASA ASRS Text

Title: ACR MAKES SLOW DESCENT RESULTING IN LESS THAN STANDARD SEPARATION.

Narrative: ACR Y WAS WBOUND ON J80 AT FL310. ACR X WAS EBND AT FL330. I DSNDED ACR X TO FL240 WHEN THE ACFT WERE 40-50 MI APART. ABOUT 45 SECS LATER, I DID NOT THINK ACR X WAS DSNDING VERY QUICKLY, SO I TOLD THE ACFT TO EXPEDITE THROUGH FL290 FOR TFC. ACR X RESPONDED AND ACKNOWLEDGED TO HURRY THROUGH FL290. I THEN OBSERVED ACR X TO BE DSNDING AT 1800-2000 FPM WHICH WOULD HAVE EASILY ENSURED SEPARATION. I TOLD THE ACFT I WOULD NEED HIM OUT OF FL290 IN A MIN AND A HALF FOR TFC, BUT WAS NOT ACKNOWLEDGED. WHEN ACR X WAS AT ROUGHLY FL300, I CALLED TFC AT 12 O'CLOCK, 15 MILES, OPPOSITE DIRECTION, FL310. I THEN TOLD ACR X I WOULD NEED A RPT OUT OF FL290 IN ABOUT 10 SECS. ABOUT 5 SECS LATER, ACR X GAVE THE FIRST VERBAL INDICATION HE WOULD HAVE SOME DIFFICULTY DOING THIS, AND ASKED THAT HE OR THE OTHER ACFT BE GIVEN A VECTOR. I TURNED ACR X 50 DEG R AND ACR Y 30 DEG R AND TOLD ACR X TO REPORT FL290. ACR X REPLIED WITH 'COMING UP ON 290'. AEDP ACTIVATED. ACR X THEN REPLIED TO MY NUMEROUS ALT REQUESTS WITH REPORTS OF FL296, AND THEN 20 SECS LATER FL295. THE TWO ACFT CLOSEST POINT WAS 1.2 MI AND 1500'. SUPPLEMENTAL INFO FROM ACN 136223. MY UNDERSTANDING IS THAT IT WOULD HAVE BEEN A PLT DEVIATION IF THE 'R' CTLR HAD TOLD THE PLT THE CENTER TIME WHEN TELLING HIM HE NEEDED HIM OUT OF FL290 IN A MIN AND A HALF OR ASSIGNED THE PLT A RATE OF DSCNT.

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.