Narrative:

Air carrier X was assigned a 345 degree heading to join J51 northeast crg. Air carrier Y checked on frequency, turning from a n-erly heading direct crg out of FL314 to FL410. I stopped air carrier Y turn and assigned a 355 degree heading. I realize the jet stream was strong. I assumed approximately 100 KTS out of w--in fact, they were closer to 150 KTS. I then turned air carrier X to 355 degrees to parallel air carrier Y. At that point, I asked air carrier Y his heading, which he replied passing through 015. At this point I told him to expedite his turn, but with the wind it pushed him into air carrier X. In my professional opinion, there are 2 critical points: 1) I assumed a heading for air carrier Y to crg, based on air carrier Y position of crg. A heading for crg should have been 015 right 020 degrees. The air carrier Y, when checking in, said he was still turning toward crg. Therefore, his new heading should have only been about 20 degrees left, and taken less than 1 min to get there. Over 1 1/2 mins later, air carrier Y was going through a 015, which must have made his original heading to crg about 030 or 040 degrees, which was too far to the east for crg. 2) I knew the winds were strong (about 100 KTS), but in fact they were closer to 150-160 KTS, I later found out.

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Original NASA ASRS Text

Title: ACR Y HAD LESS THAN STANDARD SEPARATION FROM ACR X. SYSTEM ERROR.

Narrative: ACR X WAS ASSIGNED A 345 DEG HDG TO JOIN J51 NE CRG. ACR Y CHKED ON FREQ, TURNING FROM A N-ERLY HDG DIRECT CRG OUT OF FL314 TO FL410. I STOPPED ACR Y TURN AND ASSIGNED A 355 DEG HDG. I REALIZE THE JET STREAM WAS STRONG. I ASSUMED APPROX 100 KTS OUT OF W--IN FACT, THEY WERE CLOSER TO 150 KTS. I THEN TURNED ACR X TO 355 DEGS TO PARALLEL ACR Y. AT THAT POINT, I ASKED ACR Y HIS HDG, WHICH HE REPLIED PASSING THROUGH 015. AT THIS POINT I TOLD HIM TO EXPEDITE HIS TURN, BUT WITH THE WIND IT PUSHED HIM INTO ACR X. IN MY PROFESSIONAL OPINION, THERE ARE 2 CRITICAL POINTS: 1) I ASSUMED A HDG FOR ACR Y TO CRG, BASED ON ACR Y POS OF CRG. A HDG FOR CRG SHOULD HAVE BEEN 015 R 020 DEGS. THE ACR Y, WHEN CHKING IN, SAID HE WAS STILL TURNING TOWARD CRG. THEREFORE, HIS NEW HDG SHOULD HAVE ONLY BEEN ABOUT 20 DEGS LEFT, AND TAKEN LESS THAN 1 MIN TO GET THERE. OVER 1 1/2 MINS LATER, ACR Y WAS GOING THROUGH A 015, WHICH MUST HAVE MADE HIS ORIGINAL HDG TO CRG ABOUT 030 OR 040 DEGS, WHICH WAS TOO FAR TO THE E FOR CRG. 2) I KNEW THE WINDS WERE STRONG (ABOUT 100 KTS), BUT IN FACT THEY WERE CLOSER TO 150-160 KTS, I LATER FOUND OUT.

Data retrieved from NASA's ASRS site as of August 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.