Narrative:

Air carrier X, inbound to dtw, from arrival feeder east, is handed off to controller 'a,' who is working final arrival east. Controller 'a' acknowledges and issues air carrier X descent to 5000 ft. Almost simultaneously air carrier X (identical call sign) departs dtw and contacts departure control. (Controller 'B') ARTS computer is not able to track identical call signs which leads to a limited data display on air carrier X (departure) controller 'B' recognizes the fact that duplicate call signs exist and, without realizing another active track is in progress, inadvertently removes the computer track on air carrier X (inbound). This causes air carrier X (inbound) to disappear from controller a's display leaving only a limited track indicating altitude only. Approximately 10 seconds after air carrier X (inbound) initially checked onto controller a's frequency, controller 'a' began a position relief briefing for controller 'C' who was assuming control of the sector. Controller 'a' used the position relief checklist and the relief briefing was recorded. Controller ' a' failed to recognize air carrier X had disappeared from the radar display and therefore did not include the aircraft in the briefing. Controller 'C' did not recognize the limited track on air carrier X (inbound) when he received a transmission from air carrier X (inbound) indicating he was responding to a TCASII RA being in conflict with an air carrier DC9 on approach to a parallel runway. The DC9 was in communication with controller 'D,' (final arrival west) who was also responding to a TCASII RA. Traffic was light to occasional moderate on arrival feeder sectors, and light on final arrival sectors. All arrival sector position were staffed.

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Original NASA ASRS Text

Title: D21 CTLR EXPERIENCED TCASII RA WITH ACFT WITH NO DATA BLOCK INFO.

Narrative: ACR X, INBOUND TO DTW, FROM ARR FEEDER E, IS HANDED OFF TO CTLR 'A,' WHO IS WORKING FINAL ARR E. CTLR 'A' ACKNOWLEDGES AND ISSUES ACR X DSCNT TO 5000 FT. ALMOST SIMULTANEOUSLY ACR X (IDENTICAL CALL SIGN) DEPARTS DTW AND CONTACTS DEP CTL. (CTLR 'B') ARTS COMPUTER IS NOT ABLE TO TRACK IDENTICAL CALL SIGNS WHICH LEADS TO A LIMITED DATA DISPLAY ON ACR X (DEP) CTLR 'B' RECOGNIZES THE FACT THAT DUPLICATE CALL SIGNS EXIST AND, WITHOUT REALIZING ANOTHER ACTIVE TRACK IS IN PROGRESS, INADVERTENTLY REMOVES THE COMPUTER TRACK ON ACR X (INBOUND). THIS CAUSES ACR X (INBOUND) TO DISAPPEAR FROM CTLR A'S DISPLAY LEAVING ONLY A LIMITED TRACK INDICATING ALT ONLY. APPROX 10 SECONDS AFTER ACR X (INBOUND) INITIALLY CHKED ONTO CTLR A'S FREQ, CTLR 'A' BEGAN A POS RELIEF BRIEFING FOR CTLR 'C' WHO WAS ASSUMING CTL OF THE SECTOR. CTLR 'A' USED THE POS RELIEF CHKLIST AND THE RELIEF BRIEFING WAS RECORDED. CTLR ' A' FAILED TO RECOGNIZE ACR X HAD DISAPPEARED FROM THE RADAR DISPLAY AND THEREFORE DID NOT INCLUDE THE ACFT IN THE BRIEFING. CTLR 'C' DID NOT RECOGNIZE THE LIMITED TRACK ON ACR X (INBOUND) WHEN HE RECEIVED A XMISSION FROM ACR X (INBOUND) INDICATING HE WAS RESPONDING TO A TCASII RA BEING IN CONFLICT WITH AN ACR DC9 ON APCH TO A PARALLEL RWY. THE DC9 WAS IN COM WITH CTLR 'D,' (FINAL ARR W) WHO WAS ALSO RESPONDING TO A TCASII RA. TFC WAS LIGHT TO OCCASIONAL MODERATE ON ARR FEEDER SECTORS, AND LIGHT ON FINAL ARR SECTORS. ALL ARR SECTOR POS WERE STAFFED.

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.