Narrative:

Aircraft X, descending to 11000 ft inbound to ord, was crossing near a VFR aircraft on squawk code XXXX, normally used by parachute jump aircraft. I gave aircraft X (nebound) 15 degrees left. Subsequently the VFR code YYYY (nebound) turned left 90 degrees or more (northwest) across the path of the descending aircraft X. Aircraft X announced RA, turned left and climbed to avoid. Aircraft Y (squawk code YYYY) declared stopping climb at 13000 ft. This is an ongoing daily problem at ZAU plano sector.

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Original NASA ASRS Text

Title: RPTR CONTENDS THAT CLBING VFR ACFT Y TURNED WITHOUT NOTICE INTO ACFT X, WHO WAS DSNDING AND BEING VECTORED AROUND ACFT Y. ACFT X RECEIVED AN RA AND TOOK EVASIVE ACTION TO CLR ACFT Y.

Narrative: ACFT X, DSNDING TO 11000 FT INBOUND TO ORD, WAS XING NEAR A VFR ACFT ON SQUAWK CODE XXXX, NORMALLY USED BY PARACHUTE JUMP ACFT. I GAVE ACFT X (NEBOUND) 15 DEGS L. SUBSEQUENTLY THE VFR CODE YYYY (NEBOUND) TURNED L 90 DEGS OR MORE (NW) ACROSS THE PATH OF THE DSNDING ACFT X. ACFT X ANNOUNCED RA, TURNED L AND CLBED TO AVOID. ACFT Y (SQUAWK CODE YYYY) DECLARED STOPPING CLB AT 13000 FT. THIS IS AN ONGOING DAILY PROB AT ZAU PLANO SECTOR.

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.