Narrative:

A crj was at 17000 ft departing to the west. A B712; an ewr arrival; appeared on the scope at 17000 ft in the direct path of the crj. The crj was issued evasive action and descended to avoid the B712. It turns out the B712 was a 'ghost' target erroneously projected forward by the computer. The targets appeared as real; had the conflict alert system active and after they merged; the B712 disappeared. Controllers who witnessed the event thought the B712 went down as a result of an evasive maneuver. The incident was extremely unnerving and traumatic to those who witnessed it. While it was soon discovered to be a 'ghost' target; the outcome could have still been disastrous. Controllers issuing immediate evasive instructions to air crews can create hazardous aircraft upsets with catastrophic results.

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Original NASA ASRS Text

Title: N90 CTLR DESCRIBED INCIDENT AT 17000 FT WHEN FALSE TARGET CAUSED ISSUANCE OF EVASIVE ACTION ON PERCEIVED OPPOSITE DIRECTION TFC.

Narrative: A CRJ WAS AT 17000 FT DEPARTING TO THE W. A B712; AN EWR ARR; APPEARED ON THE SCOPE AT 17000 FT IN THE DIRECT PATH OF THE CRJ. THE CRJ WAS ISSUED EVASIVE ACTION AND DSNDED TO AVOID THE B712. IT TURNS OUT THE B712 WAS A 'GHOST' TARGET ERRONEOUSLY PROJECTED FORWARD BY THE COMPUTER. THE TARGETS APPEARED AS REAL; HAD THE CONFLICT ALERT SYS ACTIVE AND AFTER THEY MERGED; THE B712 DISAPPEARED. CTLRS WHO WITNESSED THE EVENT THOUGHT THE B712 WENT DOWN AS A RESULT OF AN EVASIVE MANEUVER. THE INCIDENT WAS EXTREMELY UNNERVING AND TRAUMATIC TO THOSE WHO WITNESSED IT. WHILE IT WAS SOON DISCOVERED TO BE A 'GHOST' TARGET; THE OUTCOME COULD HAVE STILL BEEN DISASTROUS. CTLRS ISSUING IMMEDIATE EVASIVE INSTRUCTIONS TO AIR CREWS CAN CREATE HAZARDOUS ACFT UPSETS WITH CATASTROPHIC RESULTS.

Data retrieved from NASA's ASRS site as of January 2009 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.