Narrative:

I was working an overtime mid shift, and after extensive vectoring for over 2 hours around many thunderstorms throughout the area and approach changes (rapid wind shifts), the controller in charge decided to get 3 more aircraft holding at cgt into ord before severe (level 6) thunderstorms hit the airport. I was vectoring to runway 23L when I was handed off air carrier X, and air carrier Y, the third aircraft, was 20 mi behind and no factor. All 3 were cleared for their approach at 4000' (altitude because of turbulence) at 250 KTS to try to beat the WX. When air carrier X was on 15 mi final and air carrier Y 22 mi final, I issued the last of several RVR readings (about 2200') to all aircraft and advised there was a thunderstorm over the airport and requested each one's intentions. All wanted to miss. I issued miss instructions 090 degrees at 6000' to air carrier X and 090 degrees at 7000' to air carrier Y. The lead aircraft closest to the WX turned on a dime and was eastbound. The second air carrier Y didn't seem as concerned with the WX and made a very wide turn to the east, and about 3 or 4 mi east of the localizer came within 1 mi of air carrier X at 5600'. I tried to turn air carrier Y to a 040 degree heading, and told him to level at present altitude to avoid the situation. His reply was that he didn't want the heading because of WX, and kept on about how bad it was. So I cut in and told air carrier Y to turn tight to 130 degrees and expedite climb to 7000'. By then, standard sep had been lost. Controller fatigue, I feel, was a factor, along with what I consider a very poor turn rate by air carrier Y. It also seemed to me that when I leveled air carrier X at present altitude, air carrier Y did the same. I didn't say anything to either pilot on frequency about their turns, until I told air carrier Y to turn tight to 130 degrees and expedite climb.

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Original NASA ASRS Text

Title: ACR LGT MADE A WIDE TURN AND CONFLICTED WITH ACR MLG.

Narrative: I WAS WORKING AN OVERTIME MID SHIFT, AND AFTER EXTENSIVE VECTORING FOR OVER 2 HRS AROUND MANY TSTMS THROUGHOUT THE AREA AND APCH CHANGES (RAPID WIND SHIFTS), THE CTLR IN CHARGE DECIDED TO GET 3 MORE ACFT HOLDING AT CGT INTO ORD BEFORE SEVERE (LEVEL 6) TSTMS HIT THE ARPT. I WAS VECTORING TO RWY 23L WHEN I WAS HANDED OFF ACR X, AND ACR Y, THE THIRD ACFT, WAS 20 MI BEHIND AND NO FACTOR. ALL 3 WERE CLRED FOR THEIR APCH AT 4000' (ALT BECAUSE OF TURB) AT 250 KTS TO TRY TO BEAT THE WX. WHEN ACR X WAS ON 15 MI FINAL AND ACR Y 22 MI FINAL, I ISSUED THE LAST OF SEVERAL RVR READINGS (ABOUT 2200') TO ALL ACFT AND ADVISED THERE WAS A TSTM OVER THE ARPT AND REQUESTED EACH ONE'S INTENTIONS. ALL WANTED TO MISS. I ISSUED MISS INSTRUCTIONS 090 DEGS AT 6000' TO ACR X AND 090 DEGS AT 7000' TO ACR Y. THE LEAD ACFT CLOSEST TO THE WX TURNED ON A DIME AND WAS EBND. THE SECOND ACR Y DIDN'T SEEM AS CONCERNED WITH THE WX AND MADE A VERY WIDE TURN TO THE E, AND ABOUT 3 OR 4 MI E OF THE LOC CAME WITHIN 1 MI OF ACR X AT 5600'. I TRIED TO TURN ACR Y TO A 040 DEG HDG, AND TOLD HIM TO LEVEL AT PRESENT ALT TO AVOID THE SITUATION. HIS REPLY WAS THAT HE DIDN'T WANT THE HDG BECAUSE OF WX, AND KEPT ON ABOUT HOW BAD IT WAS. SO I CUT IN AND TOLD ACR Y TO TURN TIGHT TO 130 DEGS AND EXPEDITE CLB TO 7000'. BY THEN, STANDARD SEP HAD BEEN LOST. CTLR FATIGUE, I FEEL, WAS A FACTOR, ALONG WITH WHAT I CONSIDER A VERY POOR TURN RATE BY ACR Y. IT ALSO SEEMED TO ME THAT WHEN I LEVELED ACR X AT PRESENT ALT, ACR Y DID THE SAME. I DIDN'T SAY ANYTHING TO EITHER PLT ON FREQ ABOUT THEIR TURNS, UNTIL I TOLD ACR Y TO TURN TIGHT TO 130 DEGS AND EXPEDITE CLB.

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.