Narrative:

Chicago center, on frequency 134.02, cleared air carrier X direct to fam at FL350 (FL390 filed altitude and was requested but center was unable due to traffic). Just east of bdf chicago center asked us for a tight left turn of 40 degree (from 210 degree left to 170 degree) for crossing traffic at FL350. Traffic was noted at the extreme range of TCASII and visual at 1 O'clock passing well clear to our right. We then advised center of a second aircraft at FL350 in our 1 O'clock position observed both visual and on TCASII. No further turns or altitude changes were given by ATC. TCASII indicated a min of 2 mi with RA to climb as the crossing aircraft passed left to right. Evasive action was not taken as visual contact indicated no need. Supplemental information from acn 189295: approximately 5 mins later, on frequency 134.02 the controller requested a 40 degree turn to the left and said 'make it tight'. He told us of traffic passing in front of us left to right at FL350. We observed an medium large transport passing at our 1 O'clock and 6 mi according to the TCASII indications. Moments later we observed another air carrier Y at 11 O'clock passing left to right again at the same altitude. The 40 degree turn we had done put us behind the second aircraft. The TCASII indicated that aircraft at 2 mi. We also had a TCASII RA but did not follow the indications as we were visual and clear of the aircraft. Supplemental information from acn 189290: I was controling the roberts (fbs) high altitude sector just to the south of chicago. North of my sector was thunderstorms with tops to 40000 ft. Msp flts were rerted through my sector, to the west of the storms. Ord arrs were rerted through my sector, south and west of the WX. Air carrier X departed mke, sbound for mem. Air carrier X came on my frequency requesting FL390. I had traffic at 390 so cleared air carrier X to FL350. He then started deviating swesterly around storms. Air carrier medium large transport and air carrier Y wbound for msp 20 NM in trail came on my frequency as well as ord flts. Both acrs were at FL350. It had been my intention to climb air carrier X to FL370, which I neglected to do because of other duties. Conflict alert activated between first medium large transport and air carrier X. I turned air carrier X left 40 degree which effectively separated him from first medium large transport. Conflict alert activated between air carrier X and Y while air carrier X was still in his turn. Air carrier X and Y passed with 2.5 NM separation at FL350. Because of the speed of jet aircraft at cruising altitude, I believe conflict alert should be activated 3 min prior to target merge instead of 2 min.

Google
 

Original NASA ASRS Text

Title: ACR X HAD LTSS FROM ACR Y. SYS ERROR. TCASII TA RA EVASIVE ACTION NOT TAKEN. FLC VIGILANCE HAD RA ACFT VISUALLY.

Narrative: CHICAGO CENTER, ON FREQ 134.02, CLRED ACR X DIRECT TO FAM AT FL350 (FL390 FILED ALT AND WAS REQUESTED BUT CENTER WAS UNABLE DUE TO TFC). JUST E OF BDF CHICAGO CENTER ASKED US FOR A TIGHT L TURN OF 40 DEG (FROM 210 DEG L TO 170 DEG) FOR XING TFC AT FL350. TFC WAS NOTED AT THE EXTREME RANGE OF TCASII AND VISUAL AT 1 O'CLOCK PASSING WELL CLR TO OUR R. WE THEN ADVISED CENTER OF A SECOND ACFT AT FL350 IN OUR 1 O'CLOCK POS OBSERVED BOTH VISUAL AND ON TCASII. NO FURTHER TURNS OR ALT CHANGES WERE GIVEN BY ATC. TCASII INDICATED A MIN OF 2 MI WITH RA TO CLB AS THE XING ACFT PASSED L TO R. EVASIVE ACTION WAS NOT TAKEN AS VISUAL CONTACT INDICATED NO NEED. SUPPLEMENTAL INFO FROM ACN 189295: APPROX 5 MINS LATER, ON FREQ 134.02 THE CTLR REQUESTED A 40 DEG TURN TO THE L AND SAID 'MAKE IT TIGHT'. HE TOLD US OF TFC PASSING IN FRONT OF US L TO R AT FL350. WE OBSERVED AN MLG PASSING AT OUR 1 O'CLOCK AND 6 MI ACCORDING TO THE TCASII INDICATIONS. MOMENTS LATER WE OBSERVED ANOTHER ACR Y AT 11 O'CLOCK PASSING L TO R AGAIN AT THE SAME ALT. THE 40 DEG TURN WE HAD DONE PUT US BEHIND THE SECOND ACFT. THE TCASII INDICATED THAT ACFT AT 2 MI. WE ALSO HAD A TCASII RA BUT DID NOT FOLLOW THE INDICATIONS AS WE WERE VISUAL AND CLR OF THE ACFT. SUPPLEMENTAL INFO FROM ACN 189290: I WAS CTLING THE ROBERTS (FBS) HIGH ALT SECTOR JUST TO THE S OF CHICAGO. N OF MY SECTOR WAS TSTMS WITH TOPS TO 40000 FT. MSP FLTS WERE RERTED THROUGH MY SECTOR, TO THE W OF THE STORMS. ORD ARRS WERE RERTED THROUGH MY SECTOR, S AND W OF THE WX. ACR X DEPARTED MKE, SBOUND FOR MEM. ACR X CAME ON MY FREQ REQUESTING FL390. I HAD TFC AT 390 SO CLRED ACR X TO FL350. HE THEN STARTED DEVIATING SWESTERLY AROUND STORMS. ACR MLG AND ACR Y WBOUND FOR MSP 20 NM IN TRAIL CAME ON MY FREQ AS WELL AS ORD FLTS. BOTH ACRS WERE AT FL350. IT HAD BEEN MY INTENTION TO CLB ACR X TO FL370, WHICH I NEGLECTED TO DO BECAUSE OF OTHER DUTIES. CONFLICT ALERT ACTIVATED BTWN FIRST MLG AND ACR X. I TURNED ACR X L 40 DEG WHICH EFFECTIVELY SEPARATED HIM FROM FIRST MLG. CONFLICT ALERT ACTIVATED BTWN ACR X AND Y WHILE ACR X WAS STILL IN HIS TURN. ACR X AND Y PASSED WITH 2.5 NM SEPARATION AT FL350. BECAUSE OF THE SPD OF JET ACFT AT CRUISING ALT, I BELIEVE CONFLICT ALERT SHOULD BE ACTIVATED 3 MIN PRIOR TO TARGET MERGE INSTEAD OF 2 MIN.

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.