Narrative:

We were flying the downwind leg of the HOBTT2 arrival; runway 27L transition; between foger and hittt intersections; descending from 7;000 feet to 3;000 feet.at approximately 3;800 feet; TRACON amended our assigned altitude to 3;500 feet. I acknowledged the clearance and warned TRACON that we would likely dip slightly below the new assigned altitude in the process of capturing 3;500 feet. TRACON responded 'that's fine;' and advised us of VFR traffic to the northeast of us at 3;000 feet. (I do not recall the distance to the traffic at the initial call.) we briefly descended to 3;300 feet but quickly recovered to 3;500 feet.a few seconds later; a TCAS target appeared at our 11 o'clock position; 5 miles distance; 300 feet below us and climbing. PF (pilot flying) sighted the aircraft a few seconds before I did; and a moment later we received a 'climb!' 1;500 ft-per-minute TCAS RA. PF complied with the RA immediately. At this point I got a good look at the target; rolling into a right bank. According to the TCAS the beechcraft flew 100 feet below us with no lateral separation.after receiving 'clear of conflict' from TCAS; TRACON cleared us to descend to 3;000 feet; and we continued the arrival and approach.we were 'between layers' at the time of this event. It did not appear that the TRACON controller 'working' us at the time was communicating with the beechcraft--we never heard any radio traffic to or from that aircraft. I can't imagine how the operator of the beechcraft thought VFR flight through the atl class B in marginal conditions was a good idea.

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Original NASA ASRS Text

Title: A CRJ-700 Captain reported a NMAC with a Beechcraft on descent into ATL.

Narrative: We were flying the downwind leg of the HOBTT2 arrival; Runway 27L transition; between FOGER and HITTT intersections; descending from 7;000 feet to 3;000 feet.At approximately 3;800 feet; TRACON amended our assigned altitude to 3;500 feet. I acknowledged the clearance and warned TRACON that we would likely dip slightly below the new assigned altitude in the process of capturing 3;500 feet. TRACON responded 'that's fine;' and advised us of VFR traffic to the northeast of us at 3;000 feet. (I do not recall the distance to the traffic at the initial call.) We briefly descended to 3;300 feet but quickly recovered to 3;500 feet.A few seconds later; a TCAS target appeared at our 11 o'clock position; 5 miles distance; 300 feet below us and climbing. PF (Pilot Flying) sighted the aircraft a few seconds before I did; and a moment later we received a 'CLIMB!' 1;500 ft-per-minute TCAS RA. PF complied with the RA immediately. At this point I got a good look at the target; rolling into a right bank. According to the TCAS the Beechcraft flew 100 feet below us with no lateral separation.After receiving 'CLEAR OF CONFLICT' from TCAS; TRACON cleared us to descend to 3;000 feet; and we continued the arrival and approach.We were 'between layers' at the time of this event. It did not appear that the TRACON Controller 'working' us at the time was communicating with the Beechcraft--we never heard any radio traffic to or from that aircraft. I can't imagine how the operator of the Beechcraft thought VFR flight through the ATL Class B in marginal conditions was a good idea.

Data retrieved from NASA's ASRS site 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.