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ZJX controller experienced operational error at FL390 when failing to note conflicting traffic prior to issuing descent clearance through occupied altitude.
| Attributes | |
| ACN | 778921 |
| Time | |
| Date | 200803 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : amg.airport |
| State Reference | GA |
| Altitude | msl single value : 39000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zjx.artcc |
| Operator | general aviation : corporate |
| Make Model Name | Learjet 35 |
| Operating Under FAR Part | Part 91 |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zjx.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B757 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller radar : 0.4 controller time certified in position1 : 0.4 flight time total : 52 |
| ASRS Report | 778921 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar pilot : instrument |
| Experience | controller radar : 1 flight time total : 165 |
| ASRS Report | 778932 |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation |
| Independent Detector | atc equipment : conflict alert other controllera |
| Resolutory Action | controller : issued alert controller : issued new clearance flight crew : took evasive action |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 15000 vertical : 200 |
| Supplementary | |
| Problem Areas | ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
I was on position for 1 hour 40 mins the entire time with a tracker due to heavy volume at R49. I gave a descent clearance to the LR35 to FL380. The B757 was level at FL390. I continued to work the sector. I had missed the traffic in my scan. Conflict alert went off too late; separation was already lost. The LR35 climbed to FL400 and reported level. The B757 was given descent to FL370. It appeared to have 200 ft and 3.9 mi separation. I had a tracker and a d-side at the time. Neither aircraft responded to a TCAS alert. The B757 did not see the traffic. The LR35 climbed on his own.
Original NASA ASRS Text
Title: ZJX CTLR EXPERIENCED OPERROR AT FL390 WHEN FAILING TO NOTE CONFLICTING TFC PRIOR TO ISSUING DESCENT CLRNC THROUGH OCCUPIED ALT.
Narrative: I WAS ON POS FOR 1 HR 40 MINS THE ENTIRE TIME WITH A TRACKER DUE TO HVY VOLUME AT R49. I GAVE A DSCNT CLRNC TO THE LR35 TO FL380. THE B757 WAS LEVEL AT FL390. I CONTINUED TO WORK THE SECTOR. I HAD MISSED THE TFC IN MY SCAN. CONFLICT ALERT WENT OFF TOO LATE; SEPARATION WAS ALREADY LOST. THE LR35 CLBED TO FL400 AND RPTED LEVEL. THE B757 WAS GIVEN DSCNT TO FL370. IT APPEARED TO HAVE 200 FT AND 3.9 MI SEPARATION. I HAD A TRACKER AND A D-SIDE AT THE TIME. NEITHER ACFT RESPONDED TO A TCAS ALERT. THE B757 DID NOT SEE THE TFC. THE LR35 CLBED ON HIS OWN.
Data retrieved from NASA's ASRS site as of May 2009 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.