Narrative:

Cleared air carrier Z to descend and maintain FL330, no response. Realized I meant to say air carrier X. Cleared air carrier X, descend and maintain FL290, had already put FL330 in data block. Conflict alert activated with air carrier Y. When air carrier X descended past FL330, asked air carrier X verify FL330. Said no, were cleared to FL290. Told air carrier X to maintain FL330. Climbed back up to FL330.

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Original NASA ASRS Text

Title: ARTCC RADAR CTLR MISSPEAKS WITH A SIMILAR CALL SIGN SIT AND CLRS THE WRONG ACFT TO DSND RESULTING IN A LOSS OF SEPARATION.

Narrative: CLRED ACR Z TO DSND AND MAINTAIN FL330, NO RESPONSE. REALIZED I MEANT TO SAY ACR X. CLRED ACR X, DSND AND MAINTAIN FL290, HAD ALREADY PUT FL330 IN DATA BLOCK. CONFLICT ALERT ACTIVATED WITH ACR Y. WHEN ACR X DSNDED PAST FL330, ASKED ACR X VERIFY FL330. SAID NO, WERE CLRED TO FL290. TOLD ACR X TO MAINTAIN FL330. CLBED BACK UP TO FL330.

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.