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Sct controller described incident with descending B737; when aircraft reportedly conflicted with itself because of a false target anomaly.
| Attributes | |
| ACN | 720098 |
| Time | |
| Date | 200612 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | navaid : pdz.vortac |
| State Reference | CA |
| Altitude | msl single value : 14000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : sct.tracon tower : sjc.tower |
| Operator | common carrier : air carrier |
| Make Model Name | B737 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other vortac |
| Flight Phase | descent : intermediate altitude |
| Route In Use | arrival star : n/s |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : approach |
| Qualification | controller : radar |
| Experience | controller limited radar : 10 controller military : 1 controller non radar : 3 controller radar : 7 |
| ASRS Report | 720098 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | other anomaly other |
| Independent Detector | atc equipment : conflict alert other controllera |
| Resolutory Action | none taken : anomaly accepted |
| Supplementary | |
| Problem Areas | Maintenance Human Performance Navigational Facility FAA |
| Primary Problem | Ambiguous |
| Situations | |
| ATC Facility | radar equipment : sct.tracon |
Narrative:
The ARTS 3E system operates in a mosaic radar mode. The B737 target was descending via a STAR. I observed a displayed target 5 NM away from the B737 at the same altitude and converging with the B737. I checked the transponder code of the merging traffic and it was the same code as the B737. The ARTS conflict alert (ca) activated when the targets merged. After merging the targets and ARTS 3E system no longer displayed the 'ghost' target.
Original NASA ASRS Text
Title: SCT CTLR DESCRIBED INCIDENT WITH DSNDING B737; WHEN ACFT REPORTEDLY CONFLICTED WITH ITSELF BECAUSE OF A FALSE TARGET ANOMALY.
Narrative: THE ARTS 3E SYS OPERATES IN A MOSAIC RADAR MODE. THE B737 TARGET WAS DSNDING VIA A STAR. I OBSERVED A DISPLAYED TARGET 5 NM AWAY FROM THE B737 AT THE SAME ALT AND CONVERGING WITH THE B737. I CHKED THE XPONDER CODE OF THE MERGING TFC AND IT WAS THE SAME CODE AS THE B737. THE ARTS CONFLICT ALERT (CA) ACTIVATED WHEN THE TARGETS MERGED. AFTER MERGING THE TARGETS AND ARTS 3E SYS NO LONGER DISPLAYED THE 'GHOST' TARGET.
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.