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ZLA controller experienced operational error at approximately FL390 when descent clearance was issued to wrong aircraft resulting in descent to occupied altitude.
| Attributes | |
| ACN | 715642 |
| Time | |
| Date | 200610 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : zla.artcc |
| State Reference | CA |
| Altitude | msl single value : 39000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zla.artcc |
| Make Model Name | Medium Large Transport Low Wing 2 Turbojet Eng |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zla.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B757-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : enroute altitude change |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller radar : 9 |
| ASRS Report | 715642 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation |
| Independent Detector | aircraft equipment : tcas other controllera |
| Resolutory Action | none taken : anomaly accepted |
| Consequence | faa : investigated |
| Miss Distance | vertical : 900 |
| Supplementary | |
| Problem Areas | ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Air carrier X and air carrier Y were on frequency. Air carrier Z was on at FL390. Air carrier Y was issued a clearance to descend. Clearance was meant for air carrier X. Call signs were transposed and air carrier Y descended from FL400. TCAS was set off. Air carrier Y was issued a clearance to maintain FL400. Separation minimum was 900 ft when 1000 ft is required minimum.
Original NASA ASRS Text
Title: ZLA CTLR EXPERIENCED OPERROR AT APPROX FL390 WHEN DSCNT CLRNC WAS ISSUED TO WRONG ACFT RESULTING IN DSCNT TO OCCUPIED ALT.
Narrative: ACR X AND ACR Y WERE ON FREQ. ACR Z WAS ON AT FL390. ACR Y WAS ISSUED A CLRNC TO DSND. CLRNC WAS MEANT FOR ACR X. CALL SIGNS WERE TRANSPOSED AND ACR Y DSNDED FROM FL400. TCAS WAS SET OFF. ACR Y WAS ISSUED A CLRNC TO MAINTAIN FL400. SEPARATION MINIMUM WAS 900 FT WHEN 1000 FT IS REQUIRED MINIMUM.
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.