Narrative:

The problem arose due to a new computer system cut-over at company. The flight advisory messages started coming out in a different format. The dispatcher before me did not recognize the message that flight XXX cle-mia would operate as advanced section axxx. Consequently, I was never made aware of the change. I released the flight as XXX. The crew showed up and went directly to the aircraft and cle operations didn't advise them they were axxx. In the meantime, flight XXX sdf-cle had just departed late due to crew rest. Under our computer system, the second leg XXX cle-mia would not alert me until the first leg terminated. Since XXX sdf-cle was in the air, I received no 'out messages' for the second leg, nor was I looking for or expecting one. Contributing factors were that when the advisory message was sent, it was not followed up with a phone call to the previous dispatcher. The all-night dispatcher would have then put the message on my desk. This, because of the computer cut-over, led to the problem. I was made aware of the problem when ZID called and said we had 2 flts in the air at the same time with the same flight #. I immediately gave ATC a new call sign for XXX cle-mia. The incident was due to unique circumstances revolving around the company cut-over to a new computer system.

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Original NASA ASRS Text

Title: 2 ACFT WERE IN THE AIR INBOUND AND OUTBOUND NEAR CLE WITH THE SAME CALLSIGN. OUTBOUND ACFT SHOULD HAVE HAD A FOURTH DIGIT TO DISTINGUISH IT FROM THE OTHER ACFT.

Narrative: THE PROB AROSE DUE TO A NEW COMPUTER SYS CUT-OVER AT COMPANY. THE FLT ADVISORY MESSAGES STARTED COMING OUT IN A DIFFERENT FORMAT. THE DISPATCHER BEFORE ME DID NOT RECOGNIZE THE MESSAGE THAT FLT XXX CLE-MIA WOULD OPERATE AS ADVANCED SECTION AXXX. CONSEQUENTLY, I WAS NEVER MADE AWARE OF THE CHANGE. I RELEASED THE FLT AS XXX. THE CREW SHOWED UP AND WENT DIRECTLY TO THE ACFT AND CLE OPS DIDN'T ADVISE THEM THEY WERE AXXX. IN THE MEANTIME, FLT XXX SDF-CLE HAD JUST DEPARTED LATE DUE TO CREW REST. UNDER OUR COMPUTER SYS, THE SECOND LEG XXX CLE-MIA WOULD NOT ALERT ME UNTIL THE FIRST LEG TERMINATED. SINCE XXX SDF-CLE WAS IN THE AIR, I RECEIVED NO 'OUT MESSAGES' FOR THE SECOND LEG, NOR WAS I LOOKING FOR OR EXPECTING ONE. CONTRIBUTING FACTORS WERE THAT WHEN THE ADVISORY MESSAGE WAS SENT, IT WAS NOT FOLLOWED UP WITH A PHONE CALL TO THE PREVIOUS DISPATCHER. THE ALL-NIGHT DISPATCHER WOULD HAVE THEN PUT THE MESSAGE ON MY DESK. THIS, BECAUSE OF THE COMPUTER CUT-OVER, LED TO THE PROB. I WAS MADE AWARE OF THE PROB WHEN ZID CALLED AND SAID WE HAD 2 FLTS IN THE AIR AT THE SAME TIME WITH THE SAME FLT #. I IMMEDIATELY GAVE ATC A NEW CALL SIGN FOR XXX CLE-MIA. THE INCIDENT WAS DUE TO UNIQUE CIRCUMSTANCES REVOLVING AROUND THE COMPANY CUT-OVER TO A NEW COMPUTER SYS.

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.