Air carrier came in close proximity to another air carrier on a converging course.

Attributes
ACN	113735
Time
Date	198906
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : ind
State Reference	IN
Altitude	msl bound lower : 34400 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zid
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 8
ASRS Report	113735
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
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	Other
Miss Distance	vertical : 600
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Relieved radar controller and trainee. Was told air carrier X on present heading looking for direct hvq. I cleared air carrier Y direct hvq. 2 1/2 minutes later conflict alert activated. I turned air carrier X left. I turned air carrier Y left, transmission blocked. I turned air carrier Y left again, air carrier Y questioned if clearance for him. I turned air carrier Y left and descended. I turned air carrier X further left. Was unable to maintain separation.

Original NASA ASRS Text

Title: ACR CAME IN CLOSE PROX TO ANOTHER ACR ON A CONVERGING COURSE.

Narrative: RELIEVED RADAR CTLR AND TRAINEE. WAS TOLD ACR X ON PRESENT HDG LOOKING FOR DIRECT HVQ. I CLRED ACR Y DIRECT HVQ. 2 1/2 MINUTES LATER CONFLICT ALERT ACTIVATED. I TURNED ACR X LEFT. I TURNED ACR Y LEFT, XMISSION BLOCKED. I TURNED ACR Y LEFT AGAIN, ACR Y QUESTIONED IF CLRNC FOR HIM. I TURNED ACR Y LEFT AND DESCENDED. I TURNED ACR X FURTHER LEFT. WAS UNABLE TO MAINTAIN 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.