Narrative:

Had 12-15 aircraft on frequency at time. WX ahead and pilots were concerned. It was a complex operation. I was working several aircraft, no strips, and the ones we had were hard to find. There were about 2 1/2 bays of them. Air carrier X eastbound was at FL290 and requested FL330. I advised that I was unable, traffic 4 mi in trail at FL330 and faster. He wanted FL330 badly, so I advised him that the only way I could honor his request was to give him an off-course vector and bring him in behind the traffic, which he excepted. I gave him an 030 degree turn from what he was on, which was about 120 degrees. Then gave him an 090 degree heading and there was another aircraft at FL330 in the way. Turned him 180 degrees direct bae VOR on course which put him behind the original traffic. Had overlooked air carrier Y west of bae VORTAC at FL330. Had been concentrating east of bae where WX and most of the aircraft were. The manual controller brought air carrier Y to my attention. When I realized the situation, I called air carrier Y to turn to a 180 degree heading. He did not answer. I issued an 090 degree heading to air carrier X, thinking I would get him turning and go back to air carrier Y. Air carrier X questioned the turn and air carrier Y never did answer until the seventh call, which was well clear of the near miss. When I realized nothing was working I issued traffic to air carrier X 1 O'clock and 4 mi. He advised he had traffic in sight and declared a near miss a few mins later. Traffic had been heavy during the shift. I had been working west/O a break for about 1 1/2 hours and think I was getting tired. There were more aircraft in my sector besides the ones I was working. The super high sector, FL350 and up, and I were sequencing dtos traffic and some were deviating for WX. Supplemental information from acn 149438: working manual position at badger high sector. Observed potential loss of sep between air carrier X and air carrier Y and asked the radar controller, 'are you going to have enough room with that pair at 3-3-0?' the radar controller replied that he was aware of the situation and felt he was ok. About 1 min later it became apparent that the pair the radar controller was talking about wasacr Z and air carrier X, which I was talking about air carrier X and air carrier Y. The radar man called traffic to air carrier X at 1 O'clock and 4 mi. Air carrier X spotted the traffic and evaded. Radar targets were perfectly superimposed at FL330. Ntap later showed 9/10 NM and 200' sep. In retrospect, the radar controller had completely forgotten about air carrier Y. If instead of asking about 'that pair' at FL330, I had used the call signs of the 2 aircraft, the entire situation would have been avoided. Supplemental information from acn 149060: air carrier X shifted to ZAU frequency 133.32 and on initial call, 'level 290, requesting higher.' there was no response to the 'higher' request. Waited a few more mins and asked controller when air carrier X could expect a higher or FL330. He answered this time that I had traffic at FL330, 11 mi at 6 O'clock, faster, and if I would accept a vector off course he would be able to initiate the climb sooner. I accepted the offer and was vectored to 070 degrees. Several mins later he said that if I slowed down, that would help. We did and were cleared to FL330. Reaching FL330, after several mins, we were vectored 180 degrees. At this time we were 16 NM due north of badger VOR. Before the turn was complete we were further vectored to 200 degrees. (In the turn we noticed traffic 7-8 mi way, eastbound, and felt that what appeared to be a widebody transport was the traffic we were being vectored to follow.) the first officer was flying and as our aircraft heading approached 180 degrees he spotted air carrier Y, an large transport, traffic at his 1-2 O'clock position, eastbound at our altitude, 1-2 mi away. It took a few seconds for him to decide the evasive action, which was to steepen the turn and descend 200'. The aircraft was smooth and a normal maneuver. Aircraft Y passed directly in front of us at 1000-1200' latitude and 200' above. The controller had been trying to establish contact with air carrier Y, but there had been some confusion as to the correct call sign #south. Supplemental information from acn 149066: air carrier Y deviating around thunderstorms. When we finally were pretty much clear I left my seat to use the restroom. I returned to my seat as soon as I could. As I sat down and putmy headset back in I heard the controller say we had just had a near miss with aircraft at our same altitude. He said he had tried to call us 2 or 3 times with no response. The captain said he heard another flight # similar to ours and questioned the controller and asked if he was calling us. He said negative. The next he said he heard was a traffic call to air carrier X of traffic 12 O'clock, 4 mi. As stated I was not in my seat at this time, but in the restroom another set of ears would probably have avoided the problem.

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Original NASA ASRS Text

Title: ACR X HAD LESS THAN STANDARD SEPARATION FROM ACR Y. ACR X FLT CREW TOOK EVASIVE ACTION. SYSTEM ERROR.

Narrative: HAD 12-15 ACFT ON FREQ AT TIME. WX AHEAD AND PLTS WERE CONCERNED. IT WAS A COMPLEX OPERATION. I WAS WORKING SEVERAL ACFT, NO STRIPS, AND THE ONES WE HAD WERE HARD TO FIND. THERE WERE ABOUT 2 1/2 BAYS OF THEM. ACR X EBND WAS AT FL290 AND REQUESTED FL330. I ADVISED THAT I WAS UNABLE, TFC 4 MI IN TRAIL AT FL330 AND FASTER. HE WANTED FL330 BADLY, SO I ADVISED HIM THAT THE ONLY WAY I COULD HONOR HIS REQUEST WAS TO GIVE HIM AN OFF-COURSE VECTOR AND BRING HIM IN BEHIND THE TFC, WHICH HE EXCEPTED. I GAVE HIM AN 030 DEG TURN FROM WHAT HE WAS ON, WHICH WAS ABOUT 120 DEGS. THEN GAVE HIM AN 090 DEG HDG AND THERE WAS ANOTHER ACFT AT FL330 IN THE WAY. TURNED HIM 180 DEGS DIRECT BAE VOR ON COURSE WHICH PUT HIM BEHIND THE ORIGINAL TFC. HAD OVERLOOKED ACR Y W OF BAE VORTAC AT FL330. HAD BEEN CONCENTRATING E OF BAE WHERE WX AND MOST OF THE ACFT WERE. THE MANUAL CTLR BROUGHT ACR Y TO MY ATTN. WHEN I REALIZED THE SITUATION, I CALLED ACR Y TO TURN TO A 180 DEG HDG. HE DID NOT ANSWER. I ISSUED AN 090 DEG HDG TO ACR X, THINKING I WOULD GET HIM TURNING AND GO BACK TO ACR Y. ACR X QUESTIONED THE TURN AND ACR Y NEVER DID ANSWER UNTIL THE SEVENTH CALL, WHICH WAS WELL CLR OF THE NEAR MISS. WHEN I REALIZED NOTHING WAS WORKING I ISSUED TFC TO ACR X 1 O'CLOCK AND 4 MI. HE ADVISED HE HAD TFC IN SIGHT AND DECLARED A NEAR MISS A FEW MINS LATER. TFC HAD BEEN HEAVY DURING THE SHIFT. I HAD BEEN WORKING W/O A BREAK FOR ABOUT 1 1/2 HRS AND THINK I WAS GETTING TIRED. THERE WERE MORE ACFT IN MY SECTOR BESIDES THE ONES I WAS WORKING. THE SUPER HIGH SECTOR, FL350 AND UP, AND I WERE SEQUENCING DTOS TFC AND SOME WERE DEVIATING FOR WX. SUPPLEMENTAL INFO FROM ACN 149438: WORKING MANUAL POS AT BADGER HIGH SECTOR. OBSERVED POTENTIAL LOSS OF SEP BTWN ACR X AND ACR Y AND ASKED THE RADAR CTLR, 'ARE YOU GOING TO HAVE ENOUGH ROOM WITH THAT PAIR AT 3-3-0?' THE RADAR CTLR REPLIED THAT HE WAS AWARE OF THE SITUATION AND FELT HE WAS OK. ABOUT 1 MIN LATER IT BECAME APPARENT THAT THE PAIR THE RADAR CTLR WAS TALKING ABOUT WASACR Z AND ACR X, WHICH I WAS TALKING ABOUT ACR X AND ACR Y. THE RADAR MAN CALLED TFC TO ACR X AT 1 O'CLOCK AND 4 MI. ACR X SPOTTED THE TFC AND EVADED. RADAR TARGETS WERE PERFECTLY SUPERIMPOSED AT FL330. NTAP LATER SHOWED 9/10 NM AND 200' SEP. IN RETROSPECT, THE RADAR CTLR HAD COMPLETELY FORGOTTEN ABOUT ACR Y. IF INSTEAD OF ASKING ABOUT 'THAT PAIR' AT FL330, I HAD USED THE CALL SIGNS OF THE 2 ACFT, THE ENTIRE SITUATION WOULD HAVE BEEN AVOIDED. SUPPLEMENTAL INFO FROM ACN 149060: ACR X SHIFTED TO ZAU FREQ 133.32 AND ON INITIAL CALL, 'LEVEL 290, REQUESTING HIGHER.' THERE WAS NO RESPONSE TO THE 'HIGHER' REQUEST. WAITED A FEW MORE MINS AND ASKED CTLR WHEN ACR X COULD EXPECT A HIGHER OR FL330. HE ANSWERED THIS TIME THAT I HAD TFC AT FL330, 11 MI AT 6 O'CLOCK, FASTER, AND IF I WOULD ACCEPT A VECTOR OFF COURSE HE WOULD BE ABLE TO INITIATE THE CLB SOONER. I ACCEPTED THE OFFER AND WAS VECTORED TO 070 DEGS. SEVERAL MINS LATER HE SAID THAT IF I SLOWED DOWN, THAT WOULD HELP. WE DID AND WERE CLRED TO FL330. REACHING FL330, AFTER SEVERAL MINS, WE WERE VECTORED 180 DEGS. AT THIS TIME WE WERE 16 NM DUE N OF BADGER VOR. BEFORE THE TURN WAS COMPLETE WE WERE FURTHER VECTORED TO 200 DEGS. (IN THE TURN WE NOTICED TFC 7-8 MI WAY, EBND, AND FELT THAT WHAT APPEARED TO BE A WDB WAS THE TFC WE WERE BEING VECTORED TO FOLLOW.) THE F/O WAS FLYING AND AS OUR ACFT HDG APCHED 180 DEGS HE SPOTTED ACR Y, AN LGT, TFC AT HIS 1-2 O'CLOCK POS, EBND AT OUR ALT, 1-2 MI AWAY. IT TOOK A FEW SECS FOR HIM TO DECIDE THE EVASIVE ACTION, WHICH WAS TO STEEPEN THE TURN AND DSND 200'. THE ACFT WAS SMOOTH AND A NORMAL MANEUVER. ACFT Y PASSED DIRECTLY IN FRONT OF US AT 1000-1200' LAT AND 200' ABOVE. THE CTLR HAD BEEN TRYING TO ESTABLISH CONTACT WITH ACR Y, BUT THERE HAD BEEN SOME CONFUSION AS TO THE CORRECT CALL SIGN #S. SUPPLEMENTAL INFO FROM ACN 149066: ACR Y DEVIATING AROUND TSTMS. WHEN WE FINALLY WERE PRETTY MUCH CLR I LEFT MY SEAT TO USE THE RESTROOM. I RETURNED TO MY SEAT AS SOON AS I COULD. AS I SAT DOWN AND PUTMY HEADSET BACK IN I HEARD THE CTLR SAY WE HAD JUST HAD A NEAR MISS WITH ACFT AT OUR SAME ALT. HE SAID HE HAD TRIED TO CALL US 2 OR 3 TIMES WITH NO RESPONSE. THE CAPT SAID HE HEARD ANOTHER FLT # SIMILAR TO OURS AND QUESTIONED THE CTLR AND ASKED IF HE WAS CALLING US. HE SAID NEGATIVE. THE NEXT HE SAID HE HEARD WAS A TFC CALL TO ACR X OF TFC 12 O'CLOCK, 4 MI. AS STATED I WAS NOT IN MY SEAT AT THIS TIME, BUT IN THE RESTROOM ANOTHER SET OF EARS WOULD PROBABLY HAVE AVOIDED THE PROB.

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.