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Air carrier Y descent to occupied altitude had less than standard separation from mlt X. System error.
| Attributes | |
| ACN | 188026 |
| Time | |
| Date | 199108 |
| Day | Mon |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : fam |
| State Reference | MO |
| Altitude | msl bound lower : 24000 msl bound upper : 24000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zkc |
| Operator | other |
| Make Model Name | Military Transport |
| Flight Phase | cruise other |
| Route In Use | enroute : direct |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 3 Turbojet Eng |
| Flight Phase | descent other |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| ASRS Report | 188026 |
| Person 2 | |
| Affiliation | government : military |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : military |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure non adherence : required legal separation |
| Independent Detector | atc equipment other atc equipment : unspecified |
| Resolutory Action | controller : issued new clearance other |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 26400 vertical : 300 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Mlt X was traffic for stl inbounds. A j-ring was put on mlt X data block. Having stopped another inbound at FL250, until passed mlt X. FL250 was the clearance thought to have been issued to air carrier Y. After noticing air carrier Y descending through FL244, air carrier Y was turned 90 degree left and descended to FL230. Then mlt X was turned 90 degree right. Traffic was issued to air carrier Y and asked slt. Air carrier Y replied 'FL230.' air carrier Y cleared to rejoin moduc 5 arrival. Mlt X cleared back on course. Air carrier Y reported on frequency at 3100 ft. Sector 14 radar issued a heading of 250 for spacing to air carrier Y. Sector 14 radar cleared air carrier Y to descend to 2600 ft. Sector 14 radar issued a heading of 270, to join the MODUC5 arrival, to air carrier Y. Sector 14 radar cleared air carrier Y to descend to 24000 ft. Sector 14 radar controller enters a temporary altitude of 24000 ft in the data block of air carrier Y. Sector 14 radar issued traffic to mlt X on air carrier Y descending to 25000 ft. Sector 14 radar controller enters a temporary altitude of 25000 ft in the data block of air carrier Y. Conflict alert activates, air carrier Y at 24400 ft. Sector 14 radar descended air carrier Y to 23000 ft and issued a 90 degree turn to the left. Sector 14 radar issued a 90 degree right turn to mlt X. Loss of separation, closest point 4.4 mi and 300 ft. Air carrier Y reported level at 2300 ft, separation reestablished. Sector 14 radar issued a heading of 295 to join the MODUC5 arrival.
Original NASA ASRS Text
Title: ACR Y DSCNT TO OCCUPIED ALT HAD LTSS FROM MLT X. SYS ERROR.
Narrative: MLT X WAS TFC FOR STL INBOUNDS. A J-RING WAS PUT ON MLT X DATA BLOCK. HAVING STOPPED ANOTHER INBOUND AT FL250, UNTIL PASSED MLT X. FL250 WAS THE CLRNC THOUGHT TO HAVE BEEN ISSUED TO ACR Y. AFTER NOTICING ACR Y DSNDING THROUGH FL244, ACR Y WAS TURNED 90 DEG L AND DSNDED TO FL230. THEN MLT X WAS TURNED 90 DEG R. TFC WAS ISSUED TO ACR Y AND ASKED SLT. ACR Y REPLIED 'FL230.' ACR Y CLRED TO REJOIN MODUC 5 ARR. MLT X CLRED BACK ON COURSE. ACR Y RPTED ON FREQ AT 3100 FT. SECTOR 14 RADAR ISSUED A HDG OF 250 FOR SPACING TO ACR Y. SECTOR 14 RADAR CLRED ACR Y TO DSND TO 2600 FT. SECTOR 14 RADAR ISSUED A HDG OF 270, TO JOIN THE MODUC5 ARR, TO ACR Y. SECTOR 14 RADAR CLRED ACR Y TO DSND TO 24000 FT. SECTOR 14 RADAR CTLR ENTERS A TEMPORARY ALT OF 24000 FT IN THE DATA BLOCK OF ACR Y. SECTOR 14 RADAR ISSUED TFC TO MLT X ON ACR Y DSNDING TO 25000 FT. SECTOR 14 RADAR CTLR ENTERS A TEMPORARY ALT OF 25000 FT IN THE DATA BLOCK OF ACR Y. CONFLICT ALERT ACTIVATES, ACR Y AT 24400 FT. SECTOR 14 RADAR DSNDED ACR Y TO 23000 FT AND ISSUED A 90 DEG TURN TO THE L. SECTOR 14 RADAR ISSUED A 90 DEG R TURN TO MLT X. LOSS OF SEPARATION, CLOSEST POINT 4.4 MI AND 300 FT. ACR Y RPTED LEVEL AT 2300 FT, SEPARATION REESTABLISHED. SECTOR 14 RADAR ISSUED A HDG OF 295 TO JOIN THE MODUC5 ARR.
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.