SFO LCL CTLR BECOMES INVOLVED WITH MULTIPLE TASKS INVOLVING RWY CLOSURE AND FORGETS TO RECONFIGURE AMASS (ARPT MOVEMENT AREA SAFETY SYS) FROM ACTIVE TO INACTIVE.

Narrative

I WAS WORKING LCL CTL ON A MIDSHIFT WITH GND CTL AND RADAR COORDINATOR COMBINED TO MY POS. THE CIC WAS BUSY WORKING THE SUPVR'S DESK AND CLRNC DELIVERY. TFC WAS LIGHT; LNDG RWYS 28; DEPARTING RWYS 1; BUT MY WORKLOAD WAS MODERATE DUE TO WORKING COMBINED POS. THE CITY CALLED ME ON LCL FREQ TO CLOSE RWY 28R/10L; THUS INCREASING MY WORKLOAD. I HAD TO CLR TFC OFF RWY 28R; THEN CLOSE THE RWY VERBALLY WITH THE CITY; GIVE THEM TIME AND INITIALS; TURN OFF THE APCH LIGHTS; TURN OFF THE RWY LIGHTS; NOTIFY THE AS/CIC; ADVISE BAY APCH OF THE CLOSURE; CHANGE LNDG TFC TO RWY 28L (APCH DIDN'T KNOW THE RWY WOULD CLOSE); DISPLAY APPROPRIATE PLACARDS AND LCL CTL AND GND CTL POS. I ALSO HAD A DEP READY TO GO AT RWY 28L WHO I CLRED FOR TKOF. APCH CALLED BACK TO ASK WHY THE RWY HAD CLOSED AND THEN AMASS ALERTED! 'WARNING; RWY 28R OCCUPIED RWY!' THIS REALLY GOT MY ATTN! MY FIRST THOUGHT WAS THAT THE ALERT WAS FOR MY DEPARTING B767 ON RWY 28L; BUT I OBSERVED HIM ROLLING MIDFIELD ON RWY 28L JUST ABOUT TO ROTATE -- TOO LATE TO DO ANYTHING FOR THEM! I LOOKED AT THE ASDE/AMASS AND SAW THE ALERT ON RWY 28R; A TRACKED TARGET MOVING TOWARDS THE CONSTRUCTION EQUIP ON THE RWY. THE AMASS WAS REALLY JUST DOING WHAT IT IS SUPPOSED TO DO. NEITHER I NOR THE CIC HAD SET THE AMASS TO RWY 28R/10C CLOSED. IN THE FUTURE; I WILL NOT GIVE THE CITY CTL OF A RWY UNTIL I HAVE TIME TO ADJUST THE AMASS TO SHOW THE RWY CLOSED.