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Controller descended air carrier medium large transport to avoid one air carrier large transport into another air carrier large transport resulting in less than standard separation.
| Attributes | |
| ACN | 80099 |
| Time | |
| Date | 198801 |
| Day | Sat |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : ekn |
| State Reference | WV |
| Altitude | msl bound lower : 31000 msl bound upper : 32500 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdc artcc : zob |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | climbout : intermediate altitude cruise other descent other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 3 Turbojet Eng |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller military : 4 controller radar : 19 |
| ASRS Report | 80099 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : non radar |
| Qualification | controller : radar |
| Experience | controller radar : 19 |
| ASRS Report | 80100 |
| 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 none taken : insufficient time |
| Consequence | faa : investigated faa : reviewed incident with flight crew |
| Miss Distance | horizontal : 11400 vertical : 1500 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Traffic heavy and complex. Medium large transport X converging with large transport Z at FL330. I descended medium large transport X to FL290, conflict alert was activated with medium large transport X and large transport Y at FL310. Medium large transport X was told to climb immediately back to FL330, resulting in a system error of 1500' vertical and 1.9 horizontal. At the same time of this incident an aircraft flight northbound to pit was NORAC, another air carrier flight also northbound to pit temporarily lost his transponder(the all primary was being displayed), and large transport Z had not been switched over from ZID crw-high. Due to continuous frequency problem I was transmitting on the ekn rcag and receiving on the bucks elbow rcag site. The immediate alert readout showed a lateral separation of 1.9 NM. This incident occurred in an area of frequently reported beacon splits. For several computer updates during this occurrence. There were five or more targets in this immediate area. There may have been more or less than the 1.9 NM separation.
Original NASA ASRS Text
Title: CTLR DESCENDED ACR MLG TO AVOID ONE ACR LGT INTO ANOTHER ACR LGT RESULTING IN LESS THAN STANDARD SEPARATION.
Narrative: TFC HEAVY AND COMPLEX. MLG X CONVERGING WITH LGT Z AT FL330. I DESCENDED MLG X TO FL290, CONFLICT ALERT WAS ACTIVATED WITH MLG X AND LGT Y AT FL310. MLG X WAS TOLD TO CLIMB IMMEDIATELY BACK TO FL330, RESULTING IN A SYSTEM ERROR OF 1500' VERTICAL AND 1.9 HORIZONTAL. AT THE SAME TIME OF THIS INCIDENT AN ACFT FLIGHT NBOUND TO PIT WAS NORAC, ANOTHER ACR FLT ALSO NBOUND TO PIT TEMPORARILY LOST HIS TRANSPONDER(THE ALL PRIMARY WAS BEING DISPLAYED), AND LGT Z HAD NOT BEEN SWITCHED OVER FROM ZID CRW-HIGH. DUE TO CONTINUOUS FREQUENCY PROBLEM I WAS TRANSMITTING ON THE EKN RCAG AND RECEIVING ON THE BUCKS ELBOW RCAG SITE. THE IMMEDIATE ALERT READOUT SHOWED A LATERAL SEPARATION OF 1.9 NM. THIS INCIDENT OCCURRED IN AN AREA OF FREQUENTLY REPORTED BEACON SPLITS. FOR SEVERAL COMPUTER UPDATES DURING THIS OCCURRENCE. THERE WERE FIVE OR MORE TARGETS IN THIS IMMEDIATE AREA. THERE MAY HAVE BEEN MORE OR LESS THAN THE 1.9 NM SEPARATION.
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.