Narrative:

I was sitting on the d-side at 22/31/60 combined. R-side gave frequency change to aircraft X. Aircraft X took frequency then quickly came back to say 'center; we just almost had a mid air; did you see that guy?' to which the r-side responded; 'no; I see him now coming out behind you.'aircraft Y was on a 1200 code; no data block information was shown; no traffic alert went off; and the target wasn't observed until after aircraft X brought it to our attention. At the time of the event; the sectors were combined and fairly busy with lots of VFR traffic in the surrounding area.split 22 out from 31/60 when there's moderate volume at 22.

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Original NASA ASRS Text

Title: ZDC Center Controller reported a NMAC with an aircraft they had just given a frequency change to and a VFR aircraft they did not see.

Narrative: I was sitting on the D-side at 22/31/60 combined. R-side gave frequency change to Aircraft X. Aircraft X took frequency then quickly came back to say 'Center; we just almost had a mid air; did you see that guy?' To which the R-side responded; 'No; I see him now coming out behind you.'Aircraft Y was on a 1200 code; no data block information was shown; no traffic alert went off; and the target wasn't observed until after Aircraft X brought it to our attention. At the time of the event; the sectors were combined and fairly busy with lots of VFR traffic in the surrounding area.Split 22 out from 31/60 when there's moderate volume at 22.

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.