B737 crew have a conflict during climb with traffic not initially seen by the controller.

Attributes
ACN	560716
Time
Date	200209
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ztl.artcc
State Reference	NC
Altitude	msl single value : 12500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl.artcc
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Route In Use	departure sid : hornet 1
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Baron 58/58TC
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	None
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar pilot : instrument
Experience	controller radar : 18 controller time certified in position1 : 10 flight time total : 1400
ASRS Report	560716
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	other anomaly other
Independent Detector	aircraft equipment : tcas other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Miss Distance	horizontal : 1000 vertical : 300
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	Ambiguous

Narrative:

Flight xyz departed clt via naley transition of hornet 1 departure procedure. Aircraft checked on climbing to 14000 ft. Aircraft was reclred to FL230. Shortly thereafter, flight xyz advised he was taking evasive action for traffic. I observed a VFR target at 12500 ft tracking wbound. The targets appeared to merge and then resolve. Mode C intruder alert never activated during the entire event. Pilot of air carrier flight xyz advised he never saw the other aircraft. Other aircraft was subsequently idented as aircraft Y. He also stated that he did not see the B737.

Original NASA ASRS Text

Title: B737 CREW HAVE A CONFLICT DURING CLB WITH TFC NOT INITIALLY SEEN BY THE CTLR.

Narrative: FLT XYZ DEPARTED CLT VIA NALEY TRANSITION OF HORNET 1 DEP PROC. ACFT CHKED ON CLBING TO 14000 FT. ACFT WAS RECLRED TO FL230. SHORTLY THEREAFTER, FLT XYZ ADVISED HE WAS TAKING EVASIVE ACTION FOR TFC. I OBSERVED A VFR TARGET AT 12500 FT TRACKING WBOUND. THE TARGETS APPEARED TO MERGE AND THEN RESOLVE. MODE C INTRUDER ALERT NEVER ACTIVATED DURING THE ENTIRE EVENT. PLT OF ACR FLT XYZ ADVISED HE NEVER SAW THE OTHER ACFT. OTHER ACFT WAS SUBSEQUENTLY IDENTED AS ACFT Y. HE ALSO STATED THAT HE DID NOT SEE THE B737.

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