An MD88 captain reported being surprised by the sudden appearance of an rj in ZTL airspace.

Attributes
ACN	589545
Time
Date	200307
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : rmg.vortac
State Reference	GA
Altitude	msl single value : 29000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl.artcc
Operator	common carrier : air carrier
Make Model Name	MD-88
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : ztl.artcc
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	589545
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	conflict : airborne less severe
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance controller : issued alert
Miss Distance	horizontal : 18000
Supplementary
Problem Areas	ATC Human Performance
Primary Problem	ATC Human Performance

Narrative:

At cruise altitude we saw target on TCASII drifting into 5 mi arc. TCASII gave a TA. At that time, ATC directed 90 degree left turn and descent of 1000 ft. We had a visual on aircraft prior to it reaching 5 mi arc. ATC gave no calls prior to the directive action.

Original NASA ASRS Text

Title: AN MD88 CAPT RPTED BEING SURPRISED BY THE SUDDEN APPEARANCE OF AN RJ IN ZTL AIRSPACE.

Narrative: AT CRUISE ALT WE SAW TARGET ON TCASII DRIFTING INTO 5 MI ARC. TCASII GAVE A TA. AT THAT TIME, ATC DIRECTED 90 DEG L TURN AND DSCNT OF 1000 FT. WE HAD A VISUAL ON ACFT PRIOR TO IT REACHING 5 MI ARC. ATC GAVE NO CALLS PRIOR TO THE DIRECTIVE ACTION.

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.