B777-300
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 9
Distraction
Conflict Ground Conflict; Critical; Ground Incursion Runway
Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew Returned To Clearance; Flight Crew Executed Go Around / Missed Approach
Aircraft; Human Factors
I told Aircraft X to hold short of RWY 28L. The pilot read back the hold short instructions. At the same time a Controller was opening up Local Assist. Getting his chair; and was getting paper. In the process blocking the view of TWY H. Not an issue since I heard the feedback. Aircraft X slowly started to cross 28L. Ground Controller said 'He is moving.' I sent Aircraft Y around. Told Aircraft X to stop. Fabulous team work.Hard to say because if Local Assist had been opened 2 minutes later; I would have seen Aircraft X moving sooner. Ground did a great job of notifying me of the situation progressing.
SFO Tower Controller reported a runway incursion that possibly would have been missed if it weren't for the Ground Controller advising the Local Controller.