Construction workers hauled up instrument panels through hatches in the floor to the top of the tower. Officials say they are the heartbeat of the communications system.

Everything will be wired up into the consoles where air traffic controllers will be working at the top of the cab.

Workers also replaced a panel of glass on the top floor of the tower. They say they are right on schedule for the May 23 opening.

KBR official Bill Holman said, "From the tower, the FAA coordination that we've got, the other contractor who does the rest of the electronics, we are dead on target, dead on schedule."

Holman says air traffic controllers should begin their training phase in the first week of May.