Narrative:

Talking to ZNY. Clear night. Descending cleared to FL210. At approximately FL220 center informed us that there was traffic at FL200 at 5 mi. We would get lower when we passed him. Captain was flying. We both looked out the window to clear. I looked down and saw him passing FL202 at a slow rate. I said, 'your altitude' just as center cut in and asked us our altitude. I told him we had overshot and that we were correcting to FL210. He came back and said, 'well the traffic was 3 mi away and increasing. You're cleared to 11000'.' the captain had corrected to FL210 very quickly. The traffic was visible now. They were also at FL200. The closest we came was 300' and 3 mi.

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Original NASA ASRS Text

Title: FLT CREW OF MLG CLEARED DESCENT TO FL210, OVERSHOT ON DESCENT AND BECAME CONFLICT WITH TRAFFIC AT FL200.

Narrative: TALKING TO ZNY. CLEAR NIGHT. DSNDING CLRED TO FL210. AT APPROX FL220 CENTER INFORMED US THAT THERE WAS TFC AT FL200 AT 5 MI. WE WOULD GET LOWER WHEN WE PASSED HIM. CAPT WAS FLYING. WE BOTH LOOKED OUT THE WINDOW TO CLR. I LOOKED DOWN AND SAW HIM PASSING FL202 AT A SLOW RATE. I SAID, 'YOUR ALT' JUST AS CENTER CUT IN AND ASKED US OUR ALT. I TOLD HIM WE HAD OVERSHOT AND THAT WE WERE CORRECTING TO FL210. HE CAME BACK AND SAID, 'WELL THE TFC WAS 3 MI AWAY AND INCREASING. YOU'RE CLRED TO 11000'.' THE CAPT HAD CORRECTED TO FL210 VERY QUICKLY. THE TFC WAS VISIBLE NOW. THEY WERE ALSO AT FL200. THE CLOSEST WE CAME WAS 300' AND 3 MI.

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