Narrative:

Air carrier X was being vectored from the southeast to enter a downwind at auburn intersection for sea runway 34R. I forgot him on a 270 degree heading, which placed him in conflict with a departing air carrier Y west of sea VOR, climbing sebound (140 degree heading) out of about 7300 ft. Conflict alert activated very late (aircraft possibly within a mi of each other). I then vectored air carrier X onto the west downwind leg. The arrival procedures in use of sea call for aircraft to proceed to inner fixes (auburn and fourt intxns) then turn wbound or eastbound, in other words, head on. Fatigue affected my performance, as I had a quick turn-around (9 hour break) between successive shifts the day before. This is routine practice at seattle TRACON. There were numerous data blocks below my airspace. This may also have caused me to lose track of the aircraft in the clutter. I was distracted by an apparent TCA intrusion by an aircraft I had instructed to maintain VFR outside the TCA. Supplemental information from 214810. Loss of separation took place between a departing and an arriving. This occurrence may have been avoided if both controllers would have had a handoff person assisting. Staffing levels in the facility are not adequate. Also to figure into this situation is the fact that both the controllers involved in this incident were low time radar controllers. This being the first radar facility for both controllers.

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Original NASA ASRS Text

Title: CTLR FORGOT ACR X (UNAUTHORIZED UNCOORD PENETRATION OF DEP CTL AIRSPACE) HAD LTSS FROM ACR Y. SYS ERROR.

Narrative: ACR X WAS BEING VECTORED FROM THE SE TO ENTER A DOWNWIND AT AUBURN INTXN FOR SEA RWY 34R. I FORGOT HIM ON A 270 DEG HDG, WHICH PLACED HIM IN CONFLICT WITH A DEPARTING ACR Y W OF SEA VOR, CLBING SEBOUND (140 DEG HDG) OUT OF ABOUT 7300 FT. CONFLICT ALERT ACTIVATED VERY LATE (ACFT POSSIBLY WITHIN A MI OF EACH OTHER). I THEN VECTORED ACR X ONTO THE W DOWNWIND LEG. THE ARR PROCS IN USE OF SEA CALL FOR ACFT TO PROCEED TO INNER FIXES (AUBURN AND FOURT INTXNS) THEN TURN WBOUND OR EBOUND, IN OTHER WORDS, HEAD ON. FATIGUE AFFECTED MY PERFORMANCE, AS I HAD A QUICK TURN-AROUND (9 HR BREAK) BTWN SUCCESSIVE SHIFTS THE DAY BEFORE. THIS IS ROUTINE PRACTICE AT SEATTLE TRACON. THERE WERE NUMEROUS DATA BLOCKS BELOW MY AIRSPACE. THIS MAY ALSO HAVE CAUSED ME TO LOSE TRACK OF THE ACFT IN THE CLUTTER. I WAS DISTRACTED BY AN APPARENT TCA INTRUSION BY AN ACFT I HAD INSTRUCTED TO MAINTAIN VFR OUTSIDE THE TCA. SUPPLEMENTAL INFO FROM 214810. LOSS OF SEPARATION TOOK PLACE BTWN A DEPARTING AND AN ARRIVING. THIS OCCURRENCE MAY HAVE BEEN AVOIDED IF BOTH CTLRS WOULD HAVE HAD A HDOF PERSON ASSISTING. STAFFING LEVELS IN THE FACILITY ARE NOT ADEQUATE. ALSO TO FIGURE INTO THIS SITUATION IS THE FACT THAT BOTH THE CTLRS INVOLVED IN THIS INCIDENT WERE LOW TIME RADAR CTLRS. THIS BEING THE FIRST RADAR FACILITY FOR BOTH CTLRS.

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.