Two controllers and a flight crew involved describe a TCAS RA event at FL345 in ZID airspace.

Attributes
ACN	1122731
Time
Date	201310
Local Time Of Day	0001-0600
Place
Locale Reference	ZID.ARTCC
State Reference	IN
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Aircraft 2
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Person 2
Function	First Officer Pilot Not Flying
Experience	Flight Crew Last 90 Days 120 Flight Crew Total 14000 Flight Crew Type 3500
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy

Narrative:

I was working a heavy amount of traffic; but the complexity was low. I handed air carrier X off to sector 76 level at FL340; air carrier X had no issues. As air carrier X was entering sector 76 I took a handoff on air carrier Y level at FL350. Air carrier Y had no request and I left him on his route. At the point that air carrier X was 10 miles into sector 76 and air carrier Y was around 20 to 15 miles still within sector 76 I noticed the conflict alert activate. Air carrier X showed climbing through FL343 while I was talking to air carrier Y at FL350 only 7 miles apart head to head. Air carrier Y immediately reported that he may have to respond to a TCAS from the aircraft climbing in front of him. I responded 'air carrier Y roger; turn 20 degrees left vectors for traffic.' I prevented the targets from merging; it was to late prevent the loss of separation. Air carrier Y never responded to an RA and remained level at FL350. I was told that the aircraft came within 3.5 miles and 400 ft. I think this was a simple case of missed traffic. I do not have any procedural recommendations to prevent this situation.

Original NASA ASRS Text

Title: Two controllers and a flight crew involved describe a TCAS RA event at FL345 in ZID airspace.

Narrative: I was working a heavy amount of traffic; but the complexity was low. I handed Air Carrier X off to Sector 76 level at FL340; Air Carrier X had no issues. As Air Carrier X was entering Sector 76 I took a handoff on Air Carrier Y level at FL350. Air Carrier Y had no request and I left him on his route. At the point that Air Carrier X was 10 miles into Sector 76 and Air Carrier Y was around 20 to 15 miles still within Sector 76 I noticed the conflict alert activate. Air Carrier X showed climbing through FL343 while I was talking to Air Carrier Y at FL350 only 7 miles apart head to head. Air Carrier Y immediately reported that he may have to respond to a TCAS from the aircraft climbing in front of him. I responded 'Air Carrier Y Roger; turn 20 degrees left vectors for traffic.' I prevented the targets from merging; it was to late prevent the loss of separation. Air Carrier Y never responded to an RA and remained level at FL350. I was told that the aircraft came within 3.5 miles and 400 FT. I think this was a simple case of missed traffic. I do not have any procedural recommendations to prevent this situation.

Data retrieved from NASA's ASRS site as of July 2013 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.