In order to keep this WU from being massive, I'm not explaining all of the technical jargon. Got a question? Just go back to the Stage Rigging Metanode
Do Not Assume Anything when working on a fly system. And always call out what you are doing in a voice loud enough to be heard anywhere onstage.
The rigger will call out "Heads up on stage. Line #X coming in." The rigger will then bring the arbor up to the appropriate level at the loading dock. When the arbor is to the loader, the rigger will lock off the lineset and call out the amount of weight to be added or subtracted from the lineset.
The loader will raise the spreader plates and prepare for loading. Once ready, the loader will yell, "Clear for loading line #X."
At this point everyone on stage should move far away form the area below the platform, preferably to center stage. A 40 or 50 pound steel weight, when dropped from 60 feet will bounce. Getting hit by a 50 pound weight, even after the first or second bounce is not pleasant.
Once the deck is clear, the rigger will call, "You are clear for loading." The loader will the confirm by calling, "Loading line #X."
Once loading is complete the loader will lower the spreader plates and call "Loading complete." After responding with "Thank you," the rigger returns to the lineset to check the weight, again calling out that the lineset is moving to those on stage.
Repeat as necessary to balance the line.
If a counterweight slips or falls, the loader should yell "heads" as quickly as possible, thus alerting those on the stage below to run to the far side of the stage.
It is also customary as a rigger to always attempt to yell "heads" should you happen to fall, thus alerting those below to fetch a mop. This same custom is shared by many rappelers and rock climbers.
Part of the Stage Rigging metanode | 
