Narrative:

Medium large transport at FL370. Widebody transport at FL390. Widebody transport was issued a clearance to descend and maintain FL290, expedite the descent through FL350 for traffic. 1 min, 15 seconds later C/a activated (widebody transport had only descended 300'). Widebody transport was asked if he could leave FL350 in 1 min and 10 seconds. He replied, 'no problem, we'll do it.' widebody transport was leaving FL386 at this time. 2 mins and 20 seconds after the initial clearance he reported leaving FL365 and asked to report leaving FL350. 18 seconds later traffic was called for the second tie and widebody transport was asked to say his altitude. He replied FL357. 2 seconds later aedp (snitch) activated. For the first minute after an expedite clearance, widebody transport descended at 100 FPM. For the next minute, after being told he had to be there in 1 min, 10 seconds, he descended at 1800 FPM. The next 30 seconds he descended at 2200 FPM. Computer records show that in the 3 mins between the clearance and the pilot's report leaving FL350, the pilot of widebody transport only descended at an average rate of 1300 FPM on an expedite clearance. In addition, he said he would leave FL350 in 1 min, 10 seconds, when in reality it took 1 min, 33 seconds. As a result, I have been charged with an operational error, when a descent rate of only 2000 FPM would have provided sep.

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Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION OCCURRED WHEN ARTCC RADAR CTLR DESCENDED AN ACFT THAT CONFLICTED WITH AN ACFT BELOW AND ON CONVERGING COURSE.

Narrative: MLG AT FL370. WDB AT FL390. WDB WAS ISSUED A CLRNC TO DSND AND MAINTAIN FL290, EXPEDITE THE DSNT THROUGH FL350 FOR TFC. 1 MIN, 15 SECS LATER C/A ACTIVATED (WDB HAD ONLY DSNDED 300'). WDB WAS ASKED IF HE COULD LEAVE FL350 IN 1 MIN AND 10 SECS. HE REPLIED, 'NO PROB, WE'LL DO IT.' WDB WAS LEAVING FL386 AT THIS TIME. 2 MINS AND 20 SECS AFTER THE INITIAL CLRNC HE RPTED LEAVING FL365 AND ASKED TO RPT LEAVING FL350. 18 SECS LATER TFC WAS CALLED FOR THE SECOND TIE AND WDB WAS ASKED TO SAY HIS ALT. HE REPLIED FL357. 2 SECS LATER AEDP (SNITCH) ACTIVATED. FOR THE FIRST MINUTE AFTER AN EXPEDITE CLRNC, WDB DSNDED AT 100 FPM. FOR THE NEXT MINUTE, AFTER BEING TOLD HE HAD TO BE THERE IN 1 MIN, 10 SECS, HE DSNDED AT 1800 FPM. THE NEXT 30 SECS HE DSNDED AT 2200 FPM. COMPUTER RECORDS SHOW THAT IN THE 3 MINS BTWN THE CLRNC AND THE PLT'S RPT LEAVING FL350, THE PLT OF WDB ONLY DSNDED AT AN AVERAGE RATE OF 1300 FPM ON AN EXPEDITE CLRNC. IN ADDITION, HE SAID HE WOULD LEAVE FL350 IN 1 MIN, 10 SECS, WHEN IN REALITY IT TOOK 1 MIN, 33 SECS. AS A RESULT, I HAVE BEEN CHARGED WITH AN OPERROR, WHEN A DSNT RATE OF ONLY 2000 FPM WOULD HAVE PROVIDED SEP.

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.