B737 Undifferentiated or Other Model
Air Traffic Control Fully Certified
Communication Breakdown; Situational Awareness
ATC Issue All Types; Conflict Airborne Conflict
Flight Crew Executed Go Around / Missed Approach
Weather; Human Factors; Procedure
The weather at SEA was foggy and visibility was approximately 1/2 mile. A Dash 8 was departing Runway 16L. Per the LOA with S46 with his direction of flight; we have automatic turns to a 230 heading. A B737 was on final for Runway 16R. After relieving the previous Controller off of Local Assist; the B737 stated that they were going around. I heard the Local Controller instruct the pilot to execute the published missed approach. I immediately started the coordination with the 'Y' Sector at S46 about the go-around. I told them the B737 was heading 195 and maintaining an altitude of 2;000. The 'Y' Sector was training and the coordination took a little bit longer than usual. I didn't realize that the Dash 8 was issued a 230 heading and immediately switched to Departure ('Y' Sector) prior to the go-around. I overheard the Local Controller instructing the B737 to maintain visual separation with the Dash 8. 'Y' Sector called and instructed me to keep the B737 climbing; but no altitude was given. I quickly assessed the situation and noticed that the B737 was 2;000 FT and the Dash 8 was above him (I don't remember the exact altitude) and decided not to instruct Local to keep the B737 climbing. The B737 was then switched to 'Y' Sector. Given the weather situation; the Dash 8 should not have been issued the 230 heading until the B737 was landing assured. Another solution was to coordinate with S46 that the Dash 8 would be on a straight out departure to protect the possibility of a go-around. Another solution was to have the B737 fly runway heading instead of having him conduct the published missed approach.
SEA Controller described a go-around conflict event during parallel runway operations. The reporter provided several actions that would would have prevented this incident.