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

Attributes
ACN	112465
Time
Date	198905
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : tth
State Reference	IN
Altitude	msl bound lower : 31500 msl bound upper : 33000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Route In Use	enroute : on vectors enroute airway : zid
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : flight data
Qualification	controller : non radar
Experience	controller non radar : 1
ASRS Report	112465
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	other
Consequence	Other
Miss Distance	horizontal : 15000 vertical : 1500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X southbound J73 FL330. Air carrier Y initially descended to FL330. Approximately 90 seconds later air carrier Y was descended to FL310 and issued a 20 degree left turn. At this point I looked at the pvd. Air carrier X was issued a heading, then air carrier Y was told to report reaching FL310. Until the point at which I looked at the pvd, I was moderately busy performing standard manual controller duties.

Original NASA ASRS Text

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

Narrative: ACR X SBND J73 FL330. ACR Y INITIALLY DESCENDED TO FL330. APPROX 90 SECONDS LATER ACR Y WAS DESCENDED TO FL310 AND ISSUED A 20 DEG LEFT TURN. AT THIS POINT I LOOKED AT THE PVD. ACR X WAS ISSUED A HDG, THEN ACR Y WAS TOLD TO REPORT REACHING FL310. UNTIL THE POINT AT WHICH I LOOKED AT THE PVD, I WAS MODERATELY BUSY PERFORMING STANDARD MANUAL CTLR DUTIES.

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.