Narrative:

Gso is split by ZDC and ZTL airspaces which leads to numerous duplicate codes. This was one of those. At the time of occurrence, I was working west radar and final. During moderate traffic, I noted aircraft 1 flashing in handoff from ZDC. I accepted the handoff and aircraft checked in reporting descending to 12000 ft. I instructed aircraft to continue descent to 4000 ft, expect visual approach to gso. The other controller (one who had seen this happen before) advised me that I may be looking at the wrong aircraft. I toggled to look at codes and sure enough, ZDC also had one on same code as was aircraft 1. Aircraft 1 descended to 10500 ft prior to crossing boundary. Had the other controller not seen this before, aircraft 1 would have continued through 2 other aircraft. Aircraft 1's descent was stopped and no separation was lost. Factors: poor training, by never being told that such an incident could occur. Also, facility not publishing fact. I should have relied on strips, not automation! Automation has known glitches that allow errors to occur. I will read the strips better, and stop trusting automation and people who program it! Callback conversation with reporter revealed the following information: reporter aware of 2 ucr filings. Duplicate beacon codes can be assigned by both ZDC and ZTL ARTCC's. Reporter believes that ZTL will assign the ZDC aircraft another beacon code only if the aircraft is landing in the gso airspace. ZTL automation evidently allows en route transiting aircraft, in this report landing clt, to retain the same beacon code due to some internal logic. The reporter states that he is aware of approximately 6 other similar incidents within the last 12 months. The reporter advised that gso has 2 automation enhancements in the facility awaiting installation.

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Original NASA ASRS Text

Title: GSO CTLR CONCERNED WITH FACILITY ARTS IIE AUTOMATION THAT ALLOWS FOR TRANSFERENCE OF SAME, DUPLICATE ACFT BEACON CODES FOR ACFT ENTERING GSO AIRSPACE.

Narrative: GSO IS SPLIT BY ZDC AND ZTL AIRSPACES WHICH LEADS TO NUMEROUS DUPLICATE CODES. THIS WAS ONE OF THOSE. AT THE TIME OF OCCURRENCE, I WAS WORKING W RADAR AND FINAL. DURING MODERATE TFC, I NOTED ACFT 1 FLASHING IN HDOF FROM ZDC. I ACCEPTED THE HDOF AND ACFT CHKED IN RPTING DSNDING TO 12000 FT. I INSTRUCTED ACFT TO CONTINUE DSCNT TO 4000 FT, EXPECT VISUAL APCH TO GSO. THE OTHER CTLR (ONE WHO HAD SEEN THIS HAPPEN BEFORE) ADVISED ME THAT I MAY BE LOOKING AT THE WRONG ACFT. I TOGGLED TO LOOK AT CODES AND SURE ENOUGH, ZDC ALSO HAD ONE ON SAME CODE AS WAS ACFT 1. ACFT 1 DSNDED TO 10500 FT PRIOR TO XING BOUNDARY. HAD THE OTHER CTLR NOT SEEN THIS BEFORE, ACFT 1 WOULD HAVE CONTINUED THROUGH 2 OTHER ACFT. ACFT 1'S DSCNT WAS STOPPED AND NO SEPARATION WAS LOST. FACTORS: POOR TRAINING, BY NEVER BEING TOLD THAT SUCH AN INCIDENT COULD OCCUR. ALSO, FACILITY NOT PUBLISHING FACT. I SHOULD HAVE RELIED ON STRIPS, NOT AUTOMATION! AUTOMATION HAS KNOWN GLITCHES THAT ALLOW ERRORS TO OCCUR. I WILL READ THE STRIPS BETTER, AND STOP TRUSTING AUTOMATION AND PEOPLE WHO PROGRAM IT! CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR AWARE OF 2 UCR FILINGS. DUPLICATE BEACON CODES CAN BE ASSIGNED BY BOTH ZDC AND ZTL ARTCC'S. RPTR BELIEVES THAT ZTL WILL ASSIGN THE ZDC ACFT ANOTHER BEACON CODE ONLY IF THE ACFT IS LNDG IN THE GSO AIRSPACE. ZTL AUTOMATION EVIDENTLY ALLOWS ENRTE TRANSITING ACFT, IN THIS RPT LNDG CLT, TO RETAIN THE SAME BEACON CODE DUE TO SOME INTERNAL LOGIC. THE RPTR STATES THAT HE IS AWARE OF APPROX 6 OTHER SIMILAR INCIDENTS WITHIN THE LAST 12 MONTHS. THE RPTR ADVISED THAT GSO HAS 2 AUTOMATION ENHANCEMENTS IN THE FACILITY AWAITING INSTALLATION.

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.