ZID controller witnessed a loss of separation event when the controller overlooked enroute traffic a...

Narrative:

Several aircraft were deviating around weather. Two of them were landing day; one was a prop and one was a jet. The jet was put on a heading to avoid the prop traffic. The jet unknowingly asked to be turned back into the other traffic due to weather; the controller delayed the turn until the other aircraft was at a safe altitude and a descent to 3000 ft was coordinated with day approach control. The controller descended the aircraft from 12000 to 3000 and told it to contact day approach. Enroute traffic was in level flight at 11000 and was overlooked by the controller. Conflict alert did not go off until the aircraft were in close proximity due to the deviations and heading the aircraft had been on and the route line had not been updated. The controller turned the enroute aircraft 15 degrees left to ensure the aircraft were not merging and no action was taken with the other aircraft because it had already been switched to the approach control. The controller needed to be more aware of the entire picture and not get fixated on only that one particular situation. The traffic and weather situation gave the controller tunnel vision and traffic was overlooked.

Original NASA ASRS Text

Title: ZID Controller witnessed a loss of separation event when the controller overlooked enroute traffic and descended a DAY arrival aircraft through an occupied altitude; tunnel vision was listed as a causal factor.

Narrative: Several aircraft were deviating around weather. Two of them were landing DAY; one was a prop and one was a jet. The jet was put on a heading to avoid the prop traffic. The jet unknowingly asked to be turned back into the other traffic due to weather; the Controller delayed the turn until the other aircraft was at a safe altitude and a descent to 3000 FT was coordinated with DAY Approach Control. The Controller descended the aircraft from 12000 to 3000 and told it to contact DAY approach. Enroute traffic was in level flight at 11000 and was overlooked by the Controller. Conflict alert did not go off until the aircraft were in close proximity due to the deviations and heading the aircraft had been on and the route line had not been updated. The Controller turned the enroute aircraft 15 degrees left to ensure the aircraft were not merging and no action was taken with the other aircraft because it had already been switched to the Approach Control. The Controller needed to be more aware of the entire picture and not get fixated on only that one particular situation. The traffic and weather situation gave the Controller tunnel vision and traffic was overlooked.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	890635
Time
Date	201005
Local Time Of Day	1201-1800
Place
Locale Reference	ZID.ARTCC
State Reference	IN
Aircraft 1
Make Model Name	EMB ERJ 145 ER&LR
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Person 1
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Track / Heading All Types Inflight Event / Encounter Weather / Turbulence

ZID controller witnessed a loss of separation event when the controller overlooked enroute traffic and descended a day arrival aircraft through an occupied altitude; tunnel vision was listed as a causal factor.