Narrative:

I cleared an air carrier X into holding for metering and then asked him to meet a metering time inbound over the fix he was holding at but did not actually clear the aircraft inbound on the arrival. After transferring communications with air carrier X to seattle approach, the aircraft turned around (in holding) head-on with another air carrier Y at the same altitude. I turned air carrier Y (I was still talking to) immediately away and climbed him, however, separation was lost at 4.6 mi. The aircraft I was in communications with had the first aircraft in sight.

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Original NASA ASRS Text

Title: ACR X HOLDING AT SAME ALT HAD LTSS FROM ACR Y. SYS ERROR.

Narrative: I CLRED AN ACR X INTO HOLDING FOR METERING AND THEN ASKED HIM TO MEET A METERING TIME INBOUND OVER THE FIX HE WAS HOLDING AT BUT DID NOT ACTUALLY CLR THE ACFT INBOUND ON THE ARR. AFTER TRANSFERRING COMS WITH ACR X TO SEATTLE APCH, THE ACFT TURNED AROUND (IN HOLDING) HEAD-ON WITH ANOTHER ACR Y AT THE SAME ALT. I TURNED ACR Y (I WAS STILL TALKING TO) IMMEDIATELY AWAY AND CLBED HIM, HOWEVER, SEPARATION WAS LOST AT 4.6 MI. THE ACFT I WAS IN COMS WITH HAD THE FIRST ACFT IN SIGHT.

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.