Less than standard separation between air carrier X and Y. System error.

Attributes
ACN	125531
Time
Date	198910
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : iiu
State Reference	KY
Altitude	msl bound lower : 37000 msl bound upper : 37000
Environment
Flight Conditions	IMC
Light	Night
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
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller radar : 11
ASRS Report	125531
Person 2
Affiliation	government : faa
Function	controller : flight data
Qualification	controller : non radar
Experience	controller non radar : 1
ASRS Report	125542
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 : 24000 vertical : 200
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Air carrier X was on a vector to the west for spacing to ord. Air carrier Y was northeast bound on J29. Although I did not initially recognize the 2 aircraft as a potential conflict, the vector took air carrier X behind air carrier Y. When spacing was accomplished I cleared air carrier X on course. Shortly thereafter I recognized the problem but initially judged that air carrier X would still go behind air carrier Y but when air carrier X turned he picked up speed and 'caught' the crw on the backside. When I saw it was not going to clear, I turned air carrier Y and descended air carrier X too late. In short, I screwed up! Supplemental information from acn 125542: conflict alert flashed with air carrier Y. The radar person immediately told air carrier X to descend to FL350 and he acknowledged. The radar controller then told air carrier Y to turn 30 degree left several times, but he didn't reply.

Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION BETWEEN ACR X AND Y. SYSTEM ERROR.

Narrative: ACR X WAS ON A VECTOR TO THE W FOR SPACING TO ORD. ACR Y WAS NE BOUND ON J29. ALTHOUGH I DID NOT INITIALLY RECOGNIZE THE 2 ACFT AS A POTENTIAL CONFLICT, THE VECTOR TOOK ACR X BEHIND ACR Y. WHEN SPACING WAS ACCOMPLISHED I CLRED ACR X ON COURSE. SHORTLY THEREAFTER I RECOGNIZED THE PROBLEM BUT INITIALLY JUDGED THAT ACR X WOULD STILL GO BEHIND ACR Y BUT WHEN ACR X TURNED HE PICKED UP SPEED AND 'CAUGHT' THE CRW ON THE BACKSIDE. WHEN I SAW IT WAS NOT GOING TO CLEAR, I TURNED ACR Y AND DESCENDED ACR X TOO LATE. IN SHORT, I SCREWED UP! SUPPLEMENTAL INFORMATION FROM ACN 125542: CONFLICT ALERT FLASHED WITH ACR Y. THE RADAR PERSON IMMEDIATELY TOLD ACR X TO DSND TO FL350 AND HE ACKNOWLEDGED. THE RADAR CTLR THEN TOLD ACR Y TO TURN 30 DEG LEFT SEVERAL TIMES, BUT HE DIDN'T REPLY.

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.