Narrative:

While working the radar associate position, I noticed aircraft #1 in conflict with aircraft #2. I coordinated with the appropriate facilities to get control to turn both aircraft, and advised the radar controller he could turn each aircraft, as needed, to maintain separation. The radar controller turned aircraft #1 5 degrees to the right. He also turned aircraft #2 to a 290 degree heading. The situation was well under control and appeared to be working. I then heard the radar controller assign aircraft #1 a 215 degree heading, then he stated he was going to turn 10 more degrees to the right for aircraft #1 to give even more space, but in doing so, the radar controller turned aircraft #1 35 degrees back into aircraft #2. The drastic left turn appeared at first to be a false indication to me, and I told the radar controller it didn't look good. On the second radar update, I again told the radar controller the situation didn't look good and he should do something. The third radar update looked very bad and as I spoke up again to do something the radar controller initiated a descent to aircraft #1 as well as diverging turns to both aircraft. I believe time on position over the last 4 months has been at an all time high. Controllers consistently work up to 2 hours and 10 mins in one session, sometimes working a busy push and soon fall into the next push. After saying and hearing so many numbers, and concentrating so intently for long periods of time, it is easy to hear what you want to hear, and think you did what you wanted to do. During the incident traffic was slow, unfortunately a period when the controller can take a 'breather', but still must maintain a sharp concentration level.

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Original NASA ASRS Text

Title: ZID CTLR LOST SEPARATION WITH 2 ACFT AT FL310 BECAUSE OF FAULTY AVOIDANCE VECTORS.

Narrative: WHILE WORKING THE RADAR ASSOCIATE POS, I NOTICED ACFT #1 IN CONFLICT WITH ACFT #2. I COORDINATED WITH THE APPROPRIATE FACILITIES TO GET CTL TO TURN BOTH ACFT, AND ADVISED THE RADAR CTLR HE COULD TURN EACH ACFT, AS NEEDED, TO MAINTAIN SEPARATION. THE RADAR CTLR TURNED ACFT #1 5 DEGS TO THE R. HE ALSO TURNED ACFT #2 TO A 290 DEG HDG. THE SIT WAS WELL UNDER CTL AND APPEARED TO BE WORKING. I THEN HEARD THE RADAR CTLR ASSIGN ACFT #1 A 215 DEG HDG, THEN HE STATED HE WAS GOING TO TURN 10 MORE DEGS TO THE R FOR ACFT #1 TO GIVE EVEN MORE SPACE, BUT IN DOING SO, THE RADAR CTLR TURNED ACFT #1 35 DEGS BACK INTO ACFT #2. THE DRASTIC L TURN APPEARED AT FIRST TO BE A FALSE INDICATION TO ME, AND I TOLD THE RADAR CTLR IT DIDN'T LOOK GOOD. ON THE SECOND RADAR UPDATE, I AGAIN TOLD THE RADAR CTLR THE SIT DIDN'T LOOK GOOD AND HE SHOULD DO SOMETHING. THE THIRD RADAR UPDATE LOOKED VERY BAD AND AS I SPOKE UP AGAIN TO DO SOMETHING THE RADAR CTLR INITIATED A DSCNT TO ACFT #1 AS WELL AS DIVERGING TURNS TO BOTH ACFT. I BELIEVE TIME ON POS OVER THE LAST 4 MONTHS HAS BEEN AT AN ALL TIME HIGH. CTLRS CONSISTENTLY WORK UP TO 2 HRS AND 10 MINS IN ONE SESSION, SOMETIMES WORKING A BUSY PUSH AND SOON FALL INTO THE NEXT PUSH. AFTER SAYING AND HEARING SO MANY NUMBERS, AND CONCENTRATING SO INTENTLY FOR LONG PERIODS OF TIME, IT IS EASY TO HEAR WHAT YOU WANT TO HEAR, AND THINK YOU DID WHAT YOU WANTED TO DO. DURING THE INCIDENT TFC WAS SLOW, UNFORTUNATELY A PERIOD WHEN THE CTLR CAN TAKE A 'BREATHER', BUT STILL MUST MAINTAIN A SHARP CONCENTRATION LEVEL.

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.