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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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ARTCC oceanic controller descend an aircraft to FL370 which conflicted with an opposite direction aircraft at FL370.
| Attributes | |
| ACN | 159230 |
| Time | |
| Date | 199010 |
| Day | Tue |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : yyt |
| State Reference | NF |
| Altitude | msl bound lower : 37000 msl bound upper : 41000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | other |
| Make Model Name | Military Transport |
| Flight Phase | climbout : intermediate altitude cruise other descent other |
| Route In Use | enroute : atlantic enroute : other oceanic enroute airway : zny |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | other |
| Make Model Name | Military Transport |
| Flight Phase | cruise other |
| Route In Use | enroute : atlantic enroute : other oceanic |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : military |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : military |
| Experience | flight time last 90 days : 180 flight time total : 9400 flight time type : 9200 |
| ASRS Report | 159230 |
| Person 2 | |
| Affiliation | government : military |
| Function | flight crew : first officer |
| Qualification | pilot : military |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure non adherence : required legal separation |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : returned to intended course or assigned course |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 27000 vertical : 0 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Our call sign was mlt X. After crossing 41 north 050 west en route to 40 north 060 west ZNY oceanic (HF 8906) cleared us to descend from FL410 to FL370. A rather unusual request, I asked for, and received a confirmation, using our full call sign. We called level at FL370. By chance I heard mlt Y give a position report at 40N 060W going to 41N 050W at FL370. At this time I rechked past latitude/long and next latitude/long. I then advised ny oceanic of the conflict, requesting altitude change. The ZNY controller said he had just sat down, and showed no descent clearance. I rechked with other pilot and with mlt Y on company frequency. All confirmed descent clearance. ZNY then claimed descent was for mlt Z. Mlt Z said no descend clearance had been received. The mistake then became obvious to ZNY and they reclred us to FL410. By this time we had a visibility on mlt Y contrails (45 mi away). After leveling at FL410 we xed over mlt Y at about 2000' laterally. The ZNY oceanic operator who gave us our clearance was obviously new, from earlier 'stumblings' with us and other traffic on the radio. The unusual (but not that unusual) descent made us more aware, hence we caught the error. We idented ourselves at least four times using our full call sign. Possibly ZNY warning of 'like call signs' would have caught ZNY's attention.
Original NASA ASRS Text
Title: ARTCC OCEANIC CTLR DESCEND AN ACFT TO FL370 WHICH CONFLICTED WITH AN OPPOSITE DIRECTION ACFT AT FL370.
Narrative: OUR CALL SIGN WAS MLT X. AFTER XING 41 N 050 W ENRTE TO 40 N 060 W ZNY OCEANIC (HF 8906) CLRED US TO DSND FROM FL410 TO FL370. A RATHER UNUSUAL REQUEST, I ASKED FOR, AND RECEIVED A CONFIRMATION, USING OUR FULL CALL SIGN. WE CALLED LEVEL AT FL370. BY CHANCE I HEARD MLT Y GIVE A POS RPT AT 40N 060W GOING TO 41N 050W AT FL370. AT THIS TIME I RECHKED PAST LAT/LONG AND NEXT LAT/LONG. I THEN ADVISED NY OCEANIC OF THE CONFLICT, REQUESTING ALT CHANGE. THE ZNY CTLR SAID HE HAD JUST SAT DOWN, AND SHOWED NO DSNT CLRNC. I RECHKED WITH OTHER PLT AND WITH MLT Y ON COMPANY FREQ. ALL CONFIRMED DSNT CLRNC. ZNY THEN CLAIMED DSNT WAS FOR MLT Z. MLT Z SAID NO DSND CLRNC HAD BEEN RECEIVED. THE MISTAKE THEN BECAME OBVIOUS TO ZNY AND THEY RECLRED US TO FL410. BY THIS TIME WE HAD A VIS ON MLT Y CONTRAILS (45 MI AWAY). AFTER LEVELING AT FL410 WE XED OVER MLT Y AT ABOUT 2000' LATERALLY. THE ZNY OCEANIC OPERATOR WHO GAVE US OUR CLRNC WAS OBVIOUSLY NEW, FROM EARLIER 'STUMBLINGS' WITH US AND OTHER TFC ON THE RADIO. THE UNUSUAL (BUT NOT THAT UNUSUAL) DSNT MADE US MORE AWARE, HENCE WE CAUGHT THE ERROR. WE IDENTED OURSELVES AT LEAST FOUR TIMES USING OUR FULL CALL SIGN. POSSIBLY ZNY WARNING OF 'LIKE CALL SIGNS' WOULD HAVE CAUGHT ZNY'S ATTN.
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.