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ARTCC radar controller descended an air carrier B757 through the altitude of an air carrier B737 with less than 5 mi separation. When the error was noted the controller attempted to stop the B757 above the B737, but separation was lost anyway.
| Attributes | |
| ACN | 374662 |
| Time | |
| Date | 199707 |
| Day | Mon |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : duj |
| State Reference | PA |
| Altitude | msl bound lower : 20000 msl bound upper : 20500 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob tower : phl |
| Operator | common carrier : air carrier |
| Make Model Name | B757 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | descent other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar pilot : instrument |
| Experience | controller non radar : 3 controller radar : 6 flight time total : 2500 |
| ASRS Report | 374662 |
| 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 non adherence : published procedure |
| Independent Detector | atc equipment other atc equipment : unspecified other controllera |
| Resolutory Action | controller : issued new clearance none taken : unable other |
| Consequence | Other |
| Miss Distance | horizontal : 18000 vertical : 400 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Was working pit inbound sector. I descended air carrier X (B757) when air carrier Y (B737) was less than 5 mi in trail of air carrier X. When I realized my error, I attempted to reclr air carrier X to FL210 above air carrier Y at FL200. The clearance was blocked twice and when air carrier X finally accepted the clearance the aircraft was already down to FL205. I believe that a 5 mi vector line or some type of quick reference for 5 mi would have helped. Also, air carrier Y was given a vector which he did not receive.
Original NASA ASRS Text
Title: ARTCC RADAR CTLR DSNDED AN ACR B757 THROUGH THE ALT OF AN ACR B737 WITH LESS THAN 5 MI SEPARATION. WHEN THE ERROR WAS NOTED THE CTLR ATTEMPTED TO STOP THE B757 ABOVE THE B737, BUT SEPARATION WAS LOST ANYWAY.
Narrative: WAS WORKING PIT INBOUND SECTOR. I DSNDED ACR X (B757) WHEN ACR Y (B737) WAS LESS THAN 5 MI IN TRAIL OF ACR X. WHEN I REALIZED MY ERROR, I ATTEMPTED TO RECLR ACR X TO FL210 ABOVE ACR Y AT FL200. THE CLRNC WAS BLOCKED TWICE AND WHEN ACR X FINALLY ACCEPTED THE CLRNC THE ACFT WAS ALREADY DOWN TO FL205. I BELIEVE THAT A 5 MI VECTOR LINE OR SOME TYPE OF QUICK REF FOR 5 MI WOULD HAVE HELPED. ALSO, ACR Y WAS GIVEN A VECTOR WHICH HE DID NOT RECEIVE.
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.