Narrative:

As a radar controller I had just taken a position away from a trainee and was attempting to put approximately 12-16 aircraft back into an orderly flow on parallel locs. Air carrier X was vectored off a localizer and climbed to 4000 ft MSL to avoid a possible conflict. However, this vector placed air carrier X in conflict with air carrier Y, another aircraft at 4000 ft. As soon as it was recognized I issued turns to both aircraft, TA's, and gave air carrier X a descent to 3000 ft, and aircraft Y a climb to 5000 ft. However, their TCASII equipment advised them of opposite instructions to mine the end result being that the aircraft merged with 200 ft separation. Contributing factors were: a) the trainee's career was without a doubt on the line during this critical session and knowing this possibly delayed my decision to take over. B) to accomplish training I had chosen to skip a lunch break and had now worked 7 1/2 hours without the lunch break. C) training this particular individual had been particularly stressful and emotional and at the time I took the position from him, I was emotionally drained and then had to contend with 16 aircraft on final approach. D) had my control instructions agreed with those of TCASII I believe more vertical separation would have been obtained. But due to the confusion, the aircraft practically remained at the same altitude. Supplemental information from acn 261808: air carrier Y level at 3000 ft MSL on localizer for runway 19L awaiting approach clearance to execute the ILS. Approach controller was very busy issuing instructions at rapid rate (high pitched voice) sounding very unsure of herself. My first officer was attempting to call company and I was flying on the autoplt while also listening to ATC. The TCASII was very cluttered with aircraft so I reduced the range from 12 mi to 6 mi to clarify the final approach aircraft in front and those on the parallel runway 19R. The first officer returned to the 'loop' at about the time TCASII called 'traffic, traffic' at about 1:30-2 O'clock. We both noticed he was level with our altitude and thought he was on the parallel localizer. The target continued closer. At about 1/2 mi we visually spotted the aircraft an air carrier X dc-9 on a converging heading. We made a descent concurrent with TCASII instructions as the dc-9 passed overhead. The controller realizing the situation informed us to climb immediately to 5000 ft but quickly changed it to 3000 ft cleared approach and call the tower on the landing. I called and was told it was a controller trainee and the instructing controller allowed the situation to occur and removal of the instructor would occur. It is not a regular occurrence to see aircraft like this on an ILS and our complacency that he was parallel and not converging contributed to this along with an unsure controller. If it had not been for TCASII we may not be around to write this report as it told us to descend and X to climb. Due to the conversations between TCASII's had we both climbed or descended I am afraid of what could have happened.

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Original NASA ASRS Text

Title: CTLR TRAINING IN PROGRESS. MULTIPLE RWY OP. PARALLEL RWYS. ACR X CLB TO OCCUPIED ALT TCASII RA HAD NMAC LTSS FROM ACR Y. SYS ERROR. EVASIVE ACTION TAKEN.

Narrative: AS A RADAR CTLR I HAD JUST TAKEN A POS AWAY FROM A TRAINEE AND WAS ATTEMPTING TO PUT APPROX 12-16 ACFT BACK INTO AN ORDERLY FLOW ON PARALLEL LOCS. ACR X WAS VECTORED OFF A LOC AND CLBED TO 4000 FT MSL TO AVOID A POSSIBLE CONFLICT. HOWEVER, THIS VECTOR PLACED ACR X IN CONFLICT WITH ACR Y, ANOTHER ACFT AT 4000 FT. AS SOON AS IT WAS RECOGNIZED I ISSUED TURNS TO BOTH ACFT, TA'S, AND GAVE ACR X A DSCNT TO 3000 FT, AND ACFT Y A CLB TO 5000 FT. HOWEVER, THEIR TCASII EQUIP ADVISED THEM OF OPPOSITE INSTRUCTIONS TO MINE THE END RESULT BEING THAT THE ACFT MERGED WITH 200 FT SEPARATION. CONTRIBUTING FACTORS WERE: A) THE TRAINEE'S CAREER WAS WITHOUT A DOUBT ON THE LINE DURING THIS CRITICAL SESSION AND KNOWING THIS POSSIBLY DELAYED MY DECISION TO TAKE OVER. B) TO ACCOMPLISH TRAINING I HAD CHOSEN TO SKIP A LUNCH BREAK AND HAD NOW WORKED 7 1/2 HRS WITHOUT THE LUNCH BREAK. C) TRAINING THIS PARTICULAR INDIVIDUAL HAD BEEN PARTICULARLY STRESSFUL AND EMOTIONAL AND AT THE TIME I TOOK THE POS FROM HIM, I WAS EMOTIONALLY DRAINED AND THEN HAD TO CONTEND WITH 16 ACFT ON FINAL APCH. D) HAD MY CTL INSTRUCTIONS AGREED WITH THOSE OF TCASII I BELIEVE MORE VERT SEPARATION WOULD HAVE BEEN OBTAINED. BUT DUE TO THE CONFUSION, THE ACFT PRACTICALLY REMAINED AT THE SAME ALT. SUPPLEMENTAL INFO FROM ACN 261808: ACR Y LEVEL AT 3000 FT MSL ON LOC FOR RWY 19L AWAITING APCH CLRNC TO EXECUTE THE ILS. APCH CTLR WAS VERY BUSY ISSUING INSTRUCTIONS AT RAPID RATE (HIGH PITCHED VOICE) SOUNDING VERY UNSURE OF HERSELF. MY FO WAS ATTEMPTING TO CALL COMPANY AND I WAS FLYING ON THE AUTOPLT WHILE ALSO LISTENING TO ATC. THE TCASII WAS VERY CLUTTERED WITH ACFT SO I REDUCED THE RANGE FROM 12 MI TO 6 MI TO CLARIFY THE FINAL APCH ACFT IN FRONT AND THOSE ON THE PARALLEL RWY 19R. THE FO RETURNED TO THE 'LOOP' AT ABOUT THE TIME TCASII CALLED 'TFC, TFC' AT ABOUT 1:30-2 O'CLOCK. WE BOTH NOTICED HE WAS LEVEL WITH OUR ALT AND THOUGHT HE WAS ON THE PARALLEL LOC. THE TARGET CONTINUED CLOSER. AT ABOUT 1/2 MI WE VISUALLY SPOTTED THE ACFT AN ACR X DC-9 ON A CONVERGING HDG. WE MADE A DSCNT CONCURRENT WITH TCASII INSTRUCTIONS AS THE DC-9 PASSED OVERHEAD. THE CTLR REALIZING THE SIT INFORMED US TO CLB IMMEDIATELY TO 5000 FT BUT QUICKLY CHANGED IT TO 3000 FT CLRED APCH AND CALL THE TWR ON THE LNDG. I CALLED AND WAS TOLD IT WAS A CTLR TRAINEE AND THE INSTRUCTING CTLR ALLOWED THE SIT TO OCCUR AND REMOVAL OF THE INSTRUCTOR WOULD OCCUR. IT IS NOT A REGULAR OCCURRENCE TO SEE ACFT LIKE THIS ON AN ILS AND OUR COMPLACENCY THAT HE WAS PARALLEL AND NOT CONVERGING CONTRIBUTED TO THIS ALONG WITH AN UNSURE CTLR. IF IT HAD NOT BEEN FOR TCASII WE MAY NOT BE AROUND TO WRITE THIS RPT AS IT TOLD US TO DSND AND X TO CLB. DUE TO THE CONVERSATIONS BTWN TCASII'S HAD WE BOTH CLBED OR DSNDED I AM AFRAID OF WHAT COULD HAVE HAPPENED.

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.