Air carrier X had less than standard separation from air carrier Y. System error.

Attributes
ACN	148938
Time
Date	199006
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : crg
State Reference	FL
Altitude	msl bound lower : 29000 msl bound upper : 31000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : non radar
Qualification	controller : radar
Experience	controller non radar : 3 controller radar : 13
ASRS Report	148938
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
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 other
Consequence	faa : investigated
Miss Distance	horizontal : 13500 vertical : 1400
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

I was working manual position when aircraft southbound was in conflict with another aircraft northbound. I was not aware of conflict until it happened. Callback conversation with reporter revealed the following: reporter experience: 13 yrs radar, 3 yrs non radar. Aircraft types: medium large transport and large transport. Reporter stated he was not monitoring the radar controller because he was on the interphone. The sector had been busy, but was very light at the time. The radar controller had 3 aircraft, 1 of which needed to be descended to FL240. Air carrier X at FL350 needed to be descended to FL310. Air carrier Y was at FL290, opp direction to air carrier X. The controller looked at the wrong aircraft and descended air carrier X to FL240. He also issued air carrier Y as traffic at 12 O'clock, 7 mi opp direction. He then marked the flight progress strip and entered 310 in the data tag. Air carrier X acknowledged descending to FL240. Controller did not catch mistake. C/a activated. Radar controller told air carrier X to maintain FL310.

Original NASA ASRS Text

Title: ACR X HAD LESS THAN STANDARD SEPARATION FROM ACR Y. SYSTEM ERROR.

Narrative: I WAS WORKING MANUAL POS WHEN ACFT SBND WAS IN CONFLICT WITH ANOTHER ACFT NBND. I WAS NOT AWARE OF CONFLICT UNTIL IT HAPPENED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR EXPERIENCE: 13 YRS RADAR, 3 YRS NON RADAR. ACFT TYPES: MLG AND LGT. RPTR STATED HE WAS NOT MONITORING THE RADAR CTLR BECAUSE HE WAS ON THE INTERPHONE. THE SECTOR HAD BEEN BUSY, BUT WAS VERY LIGHT AT THE TIME. THE RADAR CTLR HAD 3 ACFT, 1 OF WHICH NEEDED TO BE DSNDED TO FL240. ACR X AT FL350 NEEDED TO BE DSNDED TO FL310. ACR Y WAS AT FL290, OPP DIRECTION TO ACR X. THE CTLR LOOKED AT THE WRONG ACFT AND DSNDED ACR X TO FL240. HE ALSO ISSUED ACR Y AS TFC AT 12 O'CLOCK, 7 MI OPP DIRECTION. HE THEN MARKED THE FLT PROGRESS STRIP AND ENTERED 310 IN THE DATA TAG. ACR X ACKNOWLEDGED DSNDING TO FL240. CTLR DID NOT CATCH MISTAKE. C/A ACTIVATED. RADAR CTLR TOLD ACR X TO MAINTAIN FL310.

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.