Narrative:

Flight 'xyz' was landing at its destination; controlled by another dispatcher on the domestic desk. That flight landed at XA47Z. I was in control of an international flight 'xyz' [note identical flight numbers] to a european destination which took off from the same airport at XA43Z. There was a 4 minute span when there were actually two flight xyz's in the air in the same controlled airspace; one talking to approach; and one to departure. The airport had numerous delays and ATC ground stops this evening; and the 'xyz' arrival; an A320; was delayed 1 hour 40 minutes; and the 'xyz' departure; a B767; left on-time. No warning message was received by me that I remember. I understand what a safety issue this can be; and will do what I can to prevent it from happening again.

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Original NASA ASRS Text

Title: A Dispatcher discovered after the fact that he had dispatched an international flight while the delayed inbound domestic flight with the same flight number was still in the air. The two aircraft were airborne simultaneously for approximately four minutes.

Narrative: Flight 'XYZ' was landing at its destination; controlled by another dispatcher on the domestic desk. That flight landed at XA47Z. I was in control of an international flight 'XYZ' [note identical flight numbers] to a European destination which took off from the same airport at XA43Z. There was a 4 minute span when there were actually two flight XYZ's in the air in the same controlled airspace; one talking to Approach; and one to Departure. The airport had numerous delays and ATC ground stops this evening; and the 'XYZ' arrival; an A320; was delayed 1 hour 40 minutes; and the 'XYZ' departure; a B767; left on-time. No warning message was received by me that I remember. I understand what a safety issue this can be; and will do what I can to prevent it from happening again.

Data retrieved from NASA's ASRS site as of April 2012 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.