Helicopter
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 1
Situational Awareness; Confusion; Distraction
ATC Issue All Types; Conflict Airborne Conflict
Air Traffic Control Provided Assistance
ATC Equipment / Nav Facility / Buildings; Aircraft
Aircraft X was on approach to runway 19L when Local 1 coordinated a crossing of an aircraft.  When the aircraft was exiting 19L to hold short of 19R Aircraft X appeared on the ASDE-X to be over the threshold but was on short final.  The ASDE-X never went off and since we could visually see Aircraft X he continues his approach.  In this situation even though he was on final the ASDE should have alerted us.  It was enough to make myself and other controllers concerned about our equipment and lack of safety. If certain equipment is used for safety it should be tested and checked regularly.
SNA Tower Controller reports of the ASDE-X not reporting an aircraft over the threshold while an aircraft is on the runway.