|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1801 To 2400|
|Locale Reference||atc facility : air|
|Altitude||msl bound lower : 31500|
msl bound upper : 32500
|Controlling Facilities||artcc : zob|
artcc : zdc
|Operator||common carrier : air carrier|
|Make Model Name||Large Transport, Low Wing, 3 Turbojet Eng|
|Flight Phase||descent other|
|Affiliation||government : faa|
|Function||controller : flight data|
|Qualification||controller : developmental|
|Experience||controller non radar : 1|
|Affiliation||government : faa|
|Function||controller : radar|
|Qualification||controller : radar|
|Anomaly||conflict : airborne less severe|
non adherence : required legal separation
|Independent Detector||atc equipment other atc equipment : unspecified|
|Resolutory Action||controller : issued new clearance|
|Miss Distance||horizontal : 9000|
vertical : 1000
|Primary Problem||ATC Human Performance|
|Air Traffic Incident||Operational Error|
Moderate to heavy traffic at air sector (FL240-330). Numerous inbnds to washington center on vectors for spacing; numerous inbnds to cvg and day. Medium large transport Y aircraft en route at FL310 was given clearance to FL330. He acknowledged, and controller said 'no' and issued a descent to FL330 to large transport X at FL350. There was no acknowledgement of the 'no' from the medium large transport Y at FL310. Loss of separation occurred shortly thereafter, with the controller being alerted by the conflict alert. Medium large transport Y originally at FL310 was descended back to FL310. Traffic, WX and complexity led to the problem. Standard use of phraseology would probably have prevented the conflict. Supplemental information from acn 96616. Two aircraft wbound, one at FL310 and one descending to land day. I thought I stopped the descended at FL330, but medium large transport Y at FL310 reported to climb to FL330. On reading data block, FL312 climbing I descended second medium large transport Y to FL310.
Original NASA ASRS Text
Title: ARTCC RADAR CTLR GAVE ALT ASSIGNMENT TO WRONG ACFT. USED POOR PHRASEOLOGY WHEN CORRECTING MISTAKE AND HAD LESS THAN STANDARD SEPARATION OCCUR.
Narrative: MODERATE TO HEAVY TFC AT AIR SECTOR (FL240-330). NUMEROUS INBNDS TO WASHINGTON CENTER ON VECTORS FOR SPACING; NUMEROUS INBNDS TO CVG AND DAY. MLG Y ACFT ENRTE AT FL310 WAS GIVEN CLRNC TO FL330. HE ACKNOWLEDGED, AND CTLR SAID 'NO' AND ISSUED A DSCNT TO FL330 TO LGT X AT FL350. THERE WAS NO ACKNOWLEDGEMENT OF THE 'NO' FROM THE MLG Y AT FL310. LOSS OF SEPARATION OCCURRED SHORTLY THEREAFTER, WITH THE CTLR BEING ALERTED BY THE CONFLICT ALERT. MLG Y ORIGINALLY AT FL310 WAS DSNDED BACK TO FL310. TFC, WX AND COMPLEXITY LED TO THE PROB. STANDARD USE OF PHRASEOLOGY WOULD PROBABLY HAVE PREVENTED THE CONFLICT. SUPPLEMENTAL INFO FROM ACN 96616. TWO ACFT WBOUND, ONE AT FL310 AND ONE DSNDING TO LAND DAY. I THOUGHT I STOPPED THE DESCENDED AT FL330, BUT MLG Y AT FL310 RPTED TO CLB TO FL330. ON READING DATA BLOCK, FL312 CLBING I DSNDED SECOND MLG Y TO FL310.
Data retrieved from NASA's ASRS site as of August 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.