Narrative:

Departed atl runway 27R on initial heading of 25 degrees. Passing 6000 ft MSL, departure control gave us left turn to 160 degrees. There was a line of thunderstorm cells running east/west just south of the departure corridor. About 20 degrees into the turn, I got a 'traffic, traffic' TCASII alert. I looked up and saw an ATR in my forward windscreen dead ahead and appearing level, fairly close. I could see detail on the aircraft -- propellers, ailerons, etc. I watched for a second or two looking for relative motion and saw none. Also, because of the flat gray cloud backgnd, I could not be certain of his heading. I reversed my turn hard to the right, using 45 degrees angle of bank for about 20-30 degrees of turn, then rolled level to visually reacquire the traffic. The copilot told ATC we were returning to a westerly heading and advised them of the traffic. ATC told us to maintain 7000 ft. We were passing 7500 ft climbing and accelerating past 280 KIAS in climb power (we were previously cleared to 10000 ft). I pulled the power back and let the aircraft slow a little, then started down to 7000 ft. We topped out around 8000 ft. We reported the conflict and asked ATC to 'mark the tape.' we got their phone number and I called.

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Original NASA ASRS Text

Title: AFTER DEPARTING ATL, A B767 CREW OVERTAKE AN ATR72 CAUSING A TCASII ALERT AND REQUIRING EVASIVE ACTION.

Narrative: DEPARTED ATL RWY 27R ON INITIAL HDG OF 25 DEGS. PASSING 6000 FT MSL, DEP CTL GAVE US L TURN TO 160 DEGS. THERE WAS A LINE OF TSTM CELLS RUNNING E/W JUST S OF THE DEP CORRIDOR. ABOUT 20 DEGS INTO THE TURN, I GOT A 'TFC, TFC' TCASII ALERT. I LOOKED UP AND SAW AN ATR IN MY FORWARD WINDSCREEN DEAD AHEAD AND APPEARING LEVEL, FAIRLY CLOSE. I COULD SEE DETAIL ON THE ACFT -- PROPS, AILERONS, ETC. I WATCHED FOR A SECOND OR TWO LOOKING FOR RELATIVE MOTION AND SAW NONE. ALSO, BECAUSE OF THE FLAT GRAY CLOUD BACKGND, I COULD NOT BE CERTAIN OF HIS HDG. I REVERSED MY TURN HARD TO THE R, USING 45 DEGS ANGLE OF BANK FOR ABOUT 20-30 DEGS OF TURN, THEN ROLLED LEVEL TO VISUALLY REACQUIRE THE TFC. THE COPLT TOLD ATC WE WERE RETURNING TO A WESTERLY HDG AND ADVISED THEM OF THE TFC. ATC TOLD US TO MAINTAIN 7000 FT. WE WERE PASSING 7500 FT CLBING AND ACCELERATING PAST 280 KIAS IN CLB PWR (WE WERE PREVIOUSLY CLRED TO 10000 FT). I PULLED THE PWR BACK AND LET THE ACFT SLOW A LITTLE, THEN STARTED DOWN TO 7000 FT. WE TOPPED OUT AROUND 8000 FT. WE RPTED THE CONFLICT AND ASKED ATC TO 'MARK THE TAPE.' WE GOT THEIR PHONE NUMBER AND I CALLED.

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.