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ARTCC controller had less than standard separation between 2 widebody transport aircraft while trying to establish in trail spacing.
| Attributes | |
| ACN | 91237 |
| Time | |
| Date | 198807 |
| Day | Wed |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : buf |
| State Reference | NY |
| Altitude | msl bound lower : 31000 msl bound upper : 31000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob |
| Operator | common carrier : air carrier |
| Make Model Name | Widebody, Low Wing, 3 Turbojet Eng |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Route In Use | enroute : on vectors enroute airway : zob |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Widebody, Low Wing, 3 Turbojet Eng |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| ASRS Report | 91237 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation |
| Independent Detector | atc equipment other atc equipment : unspecified other controllera |
| Resolutory Action | controller : issued new clearance other |
| Consequence | Other |
| Miss Distance | horizontal : 29034 vertical : 0 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Widebody transport X and widebody transport Y at FL280 and FL310 respectively were nwbound towards buf VOR/grb (wbound). The widebody transport X asked for, and received, a vector away from widebody transport Y directly overhead. A 280 degree heading was assigned. When the aircraft were horizontal separated by more than 5 mi, widebody transport X was cleared to maintain FL310 and assigned a 295 degree heading while widebody transport Y was on a 300 degree heading. In order to put widebody transport X intrail over buf with widebody transport Y, I assigned widebody transport Y a 330 degree heading and widebody transport X a 340 degree heading. Abeam bur I turned widebody transport Y to a 300 degree heading. With some closure of targets observed (6/7 mi) I turned widebody transport X 30 degrees further right (010 degree heading). When it appeared that widebody transport Y's beacon would touch the polygon (5 mi) around widebody transport X, I descended widebody transport X to FL290.
Original NASA ASRS Text
Title: ARTCC CTLR HAD LESS THAN STANDARD SEPARATION BETWEEN 2 WDB ACFT WHILE TRYING TO ESTABLISH IN TRAIL SPACING.
Narrative: WDB X AND WDB Y AT FL280 AND FL310 RESPECTIVELY WERE NWBOUND TOWARDS BUF VOR/GRB (WBOUND). THE WDB X ASKED FOR, AND RECEIVED, A VECTOR AWAY FROM WDB Y DIRECTLY OVERHEAD. A 280 DEG HDG WAS ASSIGNED. WHEN THE ACFT WERE HORIZ SEPARATED BY MORE THAN 5 MI, WDB X WAS CLRED TO MAINTAIN FL310 AND ASSIGNED A 295 DEG HDG WHILE WDB Y WAS ON A 300 DEG HDG. IN ORDER TO PUT WDB X INTRAIL OVER BUF WITH WDB Y, I ASSIGNED WDB Y A 330 DEG HDG AND WDB X A 340 DEG HDG. ABEAM BUR I TURNED WDB Y TO A 300 DEG HDG. WITH SOME CLOSURE OF TARGETS OBSERVED (6/7 MI) I TURNED WDB X 30 DEGS FURTHER RIGHT (010 DEG HDG). WHEN IT APPEARED THAT WDB Y'S BEACON WOULD TOUCH THE POLYGON (5 MI) AROUND WDB X, I DSNDED WDB X TO FL290.
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.