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Less than standard separation occurred when an aircraft was descend below another aircraft with less than 5 miles separation.
| Attributes | |
| ACN | 161261 |
| Time | |
| Date | 199010 |
| Day | Thu |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : mrb |
| State Reference | WV |
| Altitude | msl bound lower : 26000 msl bound upper : 26300 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdc |
| Operator | general aviation : corporate |
| Make Model Name | Light Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | descent other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | general aviation : corporate |
| Make Model Name | Small Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller radar : 1 |
| ASRS Report | 161261 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : instrument pilot : commercial |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure non adherence : required legal separation |
| Independent Detector | atc equipment other atc equipment : unspecified |
| Resolutory Action | controller : issued new clearance other |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 17580 vertical : 300 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Light transport was NORDO at FL270 5 mi west of mrb. I had pointed him out to hagerstown sector and they gave me approval to descent reference a 26000' aircraft nwbnd when the 2 aircraft were 5 mi and diverging I descended the FL270 down to 12000'. Soon after aircraft conflict alerted with small transport at 26000' and aircraft went into coast track. The track headed nebnd which at first made me think light transport started turning right so I climbed the aircraft back to FL270 to reestablish sep as quickly as I could. I asked DME position of light transport and to reset his code when I radar idented him. Aircraft was 15 mi from the traffic in conflict. I then redsnded him back to 12000'. Perception wise, I believe to have 5 mi and increasing on the 2 pieces of traffic and since our ntap only got 1 hit on the less than standard separation and the rest coast track I wonder if that one hit was bad.
Original NASA ASRS Text
Title: LESS THAN STANDARD SEPARATION OCCURRED WHEN AN ACFT WAS DESCEND BELOW ANOTHER ACFT WITH LESS THAN 5 MILES SEPARATION.
Narrative: LTT WAS NORDO AT FL270 5 MI W OF MRB. I HAD POINTED HIM OUT TO HAGERSTOWN SECTOR AND THEY GAVE ME APPROVAL TO DSNT REF A 26000' ACFT NWBND WHEN THE 2 ACFT WERE 5 MI AND DIVERGING I DSNDED THE FL270 DOWN TO 12000'. SOON AFTER ACFT CONFLICT ALERTED WITH SMT AT 26000' AND ACFT WENT INTO COAST TRACK. THE TRACK HEADED NEBND WHICH AT FIRST MADE ME THINK LTT STARTED TURNING RIGHT SO I CLBED THE ACFT BACK TO FL270 TO REESTABLISH SEP AS QUICKLY AS I COULD. I ASKED DME POS OF LTT AND TO RESET HIS CODE WHEN I RADAR IDENTED HIM. ACFT WAS 15 MI FROM THE TFC IN CONFLICT. I THEN REDSNDED HIM BACK TO 12000'. PERCEPTION WISE, I BELIEVE TO HAVE 5 MI AND INCREASING ON THE 2 PIECES OF TFC AND SINCE OUR NTAP ONLY GOT 1 HIT ON THE LTSS AND THE REST COAST TRACK I WONDER IF THAT ONE HIT WAS BAD.
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.