Narrative:

I was the controller working at fwa high altitude radar sector. Traffic was heavy and complex due to WX in outlying sectors. I initially descended air carrier X to FL280 to start descent into columbus. I also had air carrier Y on frequency at FL280 en route to ord on a vector. Neither myself, nor the manual controller (radar qualified) recognized the problem at this time. A few seconds later, I recognized the problem and began to issue clrncs to effect separation. This began while the aircraft were 12-14 mi separated though head on. I issued air carrier X a left turn to a 360 degree heading (he was on a 135 degree heading at time, in descent to FL280 out of FL284). I immediately issued a clearance to air carrier Y to make a left turn to heading of 180 degrees, hoping to save situation by providing lateral separation. Air carrier Y acknowledged turn, air carrier X did not. I reclred air carrier X to expedite to FL270 and eventually to FL250 thinking that an aircraft already in descent can increase rate quickly while aircraft in level flight couldn't. No response from air carrier X. At this time I noticed air carrier Y altitude readout now showed FL275. My first inclination was a mode 'C' swap due to other aircraft in vicinity but I queried air carrier Y without adequate response. The air carrier Y also had not started turn nor had air carrier X. I again restated altitude clearance to air carrier X figuring air carrier Y was into turn and level at FL280, got a garbled response. I then saw air carrier Y altitude readout showing FL271 and then air carrier Y altitude now showed FL274. I immediately asked for altitude on air carrier Y again and restated he was supposed to be at FL280. He replied he was at FL268 and responding to TCASII 'RA.' by this time, the aircraft were past each other safely. I do not know whether air carrier X also responded to TCASII 'RA' and shallowed out his descent or just never got the first and second clrncs for an expedited descent or turn. Throughout the whole sequence, I believed air carrier Y flight was in the turn away from air carrier X. There was 25 seconds from clearance to loss of 5 mi separation and if air carrier Y had turned and air carrier X not turned, air carrier X would have passed behind. Whatever else occurred, massive confusion was caused when neither aircraft turned and then air carrier Y descended while I still thought air carrier X was expediting to a lower altitude. I have been doing this for 25 yrs and have never been so scared, confused and mad all at the same time. I literally had no idea what else to do to try and separate those aircraft. How to prevent this particular scenario from re-occurring I'm not quite sure. I'm human and mistakes happen. In this case, I thought I had caught the mistake in time to keep the aircraft from being as close as they were but nothing I did seemed to take any effect. Supplemental information from acn 314160: center told us to make 'an immediate left turn to 180 degrees, keep it tight.' after 2-3 seconds into the left turn, we got a TCASII RA, 'descend, descend!' captain took aircraft, deployed spdbrakes, dumped the nose and brought power levers to idle, to comply with RA. There was a lot of chatter on the radio, and I do not remember anything that was said after our 'turn to 180 degrees,' though I do remember that the controller's voice was 'panicky.' we were about FL265 when I saw the aircraft go over the top of us. The controller had vectored us into the traffic, and if it wasn't for the TCASII system, we would have flown head-on into the other aircraft at a closure rate of over 1000 mph! Passenger and flight attendants were startled but uninjured. Supplemental information from acn 313652: our TCASII issued a TA, followed immediately by a 'descend' RA commanding approximately a 2000 FPM descent. I immediately began to search for the traffic indicated on the TCASII. I do not recall what else was said by ZAU, however, I do know the controller was talking to several aircraft. I believe he called us more than once and we did not answer the call due to the approaching traffic. Approximately 15-20 seconds after the initial TCASII RA, I saw another aircraft pass overhead and to the left of our aircraft. I also believe our left turn, instructed by ATC, probably caused us to come closer to the other aircraft. I believe we turned left to at least 200 degrees before turning right again. When initially seen on our TCASII, the other aircraft was directly off our nose, opposite direction, approximately 600 ft above us, descending. Our aircraft was initially slow to respond to the TCASII alert (1-3 seconds delay). Supplemental information from acn 313660: at cruise, FL290, center told us to descend to FL240. Approximately 10 seconds later while on a 120 degree heading, center told us to turn 360 degrees and get to FL240. He told air carrier Y flight to turn a heading and altitude. Approximately 5 seconds later our TCASII alerted us of traffic. TCASII then went into a RA. It gave us a monitor vertical speed alert. Center was still yelling to turn to 360 degrees and descend to FL240. We could tell his voice was quite frazzled. TCASII RA changed to 'climb, climb.' we stopped our turn and started a shallow climb. We looked to see the B727 in a right turn approximately 800 ft from us. We both are totally convinced that because of TCASII we avoided getting closer to the B727. We followed the RA as displayed and everything worked out great.

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Original NASA ASRS Text

Title: OPERROR LOSS OF SEPARATION BTWN ACR X AND ACR Y ON CONVERGING OPPOSITE DIRECTION COURSE AT THE SAME ALT.

Narrative: I WAS THE CTLR WORKING AT FWA HIGH ALT RADAR SECTOR. TFC WAS HVY AND COMPLEX DUE TO WX IN OUTLYING SECTORS. I INITIALLY DSNDED ACR X TO FL280 TO START DSCNT INTO COLUMBUS. I ALSO HAD ACR Y ON FREQ AT FL280 ENRTE TO ORD ON A VECTOR. NEITHER MYSELF, NOR THE MANUAL CTLR (RADAR QUALIFIED) RECOGNIZED THE PROB AT THIS TIME. A FEW SECONDS LATER, I RECOGNIZED THE PROB AND BEGAN TO ISSUE CLRNCS TO EFFECT SEPARATION. THIS BEGAN WHILE THE ACFT WERE 12-14 MI SEPARATED THOUGH HEAD ON. I ISSUED ACR X A L TURN TO A 360 DEG HDG (HE WAS ON A 135 DEG HDG AT TIME, IN DSCNT TO FL280 OUT OF FL284). I IMMEDIATELY ISSUED A CLRNC TO ACR Y TO MAKE A L TURN TO HDG OF 180 DEGS, HOPING TO SAVE SIT BY PROVIDING LATERAL SEPARATION. ACR Y ACKNOWLEDGED TURN, ACR X DID NOT. I RECLRED ACR X TO EXPEDITE TO FL270 AND EVENTUALLY TO FL250 THINKING THAT AN ACFT ALREADY IN DSCNT CAN INCREASE RATE QUICKLY WHILE ACFT IN LEVEL FLT COULDN'T. NO RESPONSE FROM ACR X. AT THIS TIME I NOTICED ACR Y ALT READOUT NOW SHOWED FL275. MY FIRST INCLINATION WAS A MODE 'C' SWAP DUE TO OTHER ACFT IN VICINITY BUT I QUERIED ACR Y WITHOUT ADEQUATE RESPONSE. THE ACR Y ALSO HAD NOT STARTED TURN NOR HAD ACR X. I AGAIN RESTATED ALT CLRNC TO ACR X FIGURING ACR Y WAS INTO TURN AND LEVEL AT FL280, GOT A GARBLED RESPONSE. I THEN SAW ACR Y ALT READOUT SHOWING FL271 AND THEN ACR Y ALT NOW SHOWED FL274. I IMMEDIATELY ASKED FOR ALT ON ACR Y AGAIN AND RESTATED HE WAS SUPPOSED TO BE AT FL280. HE REPLIED HE WAS AT FL268 AND RESPONDING TO TCASII 'RA.' BY THIS TIME, THE ACFT WERE PAST EACH OTHER SAFELY. I DO NOT KNOW WHETHER ACR X ALSO RESPONDED TO TCASII 'RA' AND SHALLOWED OUT HIS DSCNT OR JUST NEVER GOT THE FIRST AND SECOND CLRNCS FOR AN EXPEDITED DSCNT OR TURN. THROUGHOUT THE WHOLE SEQUENCE, I BELIEVED ACR Y FLT WAS IN THE TURN AWAY FROM ACR X. THERE WAS 25 SECONDS FROM CLRNC TO LOSS OF 5 MI SEPARATION AND IF ACR Y HAD TURNED AND ACR X NOT TURNED, ACR X WOULD HAVE PASSED BEHIND. WHATEVER ELSE OCCURRED, MASSIVE CONFUSION WAS CAUSED WHEN NEITHER ACFT TURNED AND THEN ACR Y DSNDED WHILE I STILL THOUGHT ACR X WAS EXPEDITING TO A LOWER ALT. I HAVE BEEN DOING THIS FOR 25 YRS AND HAVE NEVER BEEN SO SCARED, CONFUSED AND MAD ALL AT THE SAME TIME. I LITERALLY HAD NO IDEA WHAT ELSE TO DO TO TRY AND SEPARATE THOSE ACFT. HOW TO PREVENT THIS PARTICULAR SCENARIO FROM RE-OCCURRING I'M NOT QUITE SURE. I'M HUMAN AND MISTAKES HAPPEN. IN THIS CASE, I THOUGHT I HAD CAUGHT THE MISTAKE IN TIME TO KEEP THE ACFT FROM BEING AS CLOSE AS THEY WERE BUT NOTHING I DID SEEMED TO TAKE ANY EFFECT. SUPPLEMENTAL INFO FROM ACN 314160: CTR TOLD US TO MAKE 'AN IMMEDIATE L TURN TO 180 DEGS, KEEP IT TIGHT.' AFTER 2-3 SECONDS INTO THE L TURN, WE GOT A TCASII RA, 'DSND, DSND!' CAPT TOOK ACFT, DEPLOYED SPDBRAKES, DUMPED THE NOSE AND BROUGHT PWR LEVERS TO IDLE, TO COMPLY WITH RA. THERE WAS A LOT OF CHATTER ON THE RADIO, AND I DO NOT REMEMBER ANYTHING THAT WAS SAID AFTER OUR 'TURN TO 180 DEGS,' THOUGH I DO REMEMBER THAT THE CTLR'S VOICE WAS 'PANICKY.' WE WERE ABOUT FL265 WHEN I SAW THE ACFT GO OVER THE TOP OF US. THE CTLR HAD VECTORED US INTO THE TFC, AND IF IT WASN'T FOR THE TCASII SYS, WE WOULD HAVE FLOWN HEAD-ON INTO THE OTHER ACFT AT A CLOSURE RATE OF OVER 1000 MPH! PAX AND FLT ATTENDANTS WERE STARTLED BUT UNINJURED. SUPPLEMENTAL INFO FROM ACN 313652: OUR TCASII ISSUED A TA, FOLLOWED IMMEDIATELY BY A 'DSND' RA COMMANDING APPROX A 2000 FPM DSCNT. I IMMEDIATELY BEGAN TO SEARCH FOR THE TFC INDICATED ON THE TCASII. I DO NOT RECALL WHAT ELSE WAS SAID BY ZAU, HOWEVER, I DO KNOW THE CTLR WAS TALKING TO SEVERAL ACFT. I BELIEVE HE CALLED US MORE THAN ONCE AND WE DID NOT ANSWER THE CALL DUE TO THE APCHING TFC. APPROX 15-20 SECONDS AFTER THE INITIAL TCASII RA, I SAW ANOTHER ACFT PASS OVERHEAD AND TO THE L OF OUR ACFT. I ALSO BELIEVE OUR L TURN, INSTRUCTED BY ATC, PROBABLY CAUSED US TO COME CLOSER TO THE OTHER ACFT. I BELIEVE WE TURNED L TO AT LEAST 200 DEGS BEFORE TURNING R AGAIN. WHEN INITIALLY SEEN ON OUR TCASII, THE OTHER ACFT WAS DIRECTLY OFF OUR NOSE, OPPOSITE DIRECTION, APPROX 600 FT ABOVE US, DSNDING. OUR ACFT WAS INITIALLY SLOW TO RESPOND TO THE TCASII ALERT (1-3 SECONDS DELAY). SUPPLEMENTAL INFO FROM ACN 313660: AT CRUISE, FL290, CTR TOLD US TO DSND TO FL240. APPROX 10 SECONDS LATER WHILE ON A 120 DEG HDG, CTR TOLD US TO TURN 360 DEGS AND GET TO FL240. HE TOLD ACR Y FLT TO TURN A HDG AND ALT. APPROX 5 SECONDS LATER OUR TCASII ALERTED US OF TFC. TCASII THEN WENT INTO A RA. IT GAVE US A MONITOR VERT SPD ALERT. CTR WAS STILL YELLING TO TURN TO 360 DEGS AND DSND TO FL240. WE COULD TELL HIS VOICE WAS QUITE FRAZZLED. TCASII RA CHANGED TO 'CLB, CLB.' WE STOPPED OUR TURN AND STARTED A SHALLOW CLB. WE LOOKED TO SEE THE B727 IN A R TURN APPROX 800 FT FROM US. WE BOTH ARE TOTALLY CONVINCED THAT BECAUSE OF TCASII WE AVOIDED GETTING CLOSER TO THE B727. WE FOLLOWED THE RA AS DISPLAYED AND EVERYTHING WORKED OUT GREAT.

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.