Walk along the fly rails in the designated wing of your theatre (most commonly stage left). Ensure that each batten has been raised to its resting level above the proscenium arch and that each rope lock as been firmly engaged.
Calculate the amount of weight currently distributed on each batten and ensure that the correct quantity of steel weights has been loaded on each arbor. Count the number of lighting instruments and dimmer boxes on each of your "electrics," or lighting battens, and multiply each lighting fixture by the amount of weight each one weighs. Repeat this step for any "soft goods" such as curtains, drapes or cycloramas suspended from battens.
Familiarize yourself with the amount of pounds that each of your steel weights weighs. Count the weights currently loaded into the arbor of each fly rail and ensure that the total weight of each batten load corresponds with the weight applied to each arbor.
Add or remove steel weights from the arbor as necessary---this may involve climbing the stage ladder to the "mid rail" or loading gallery if the arbor is out of reach from the stage floor. Make sure that the stage is clear when loading or unloading from the mid rail.
Test the weight distribution on your fly rails by placing your hand on the purchase line---the rope nearest you when facing the fly rail---and gently releasing the safety ring and rope lock. If your calculations are correct, the rope will remain in place and not move until you pull up or down to bring each batten in. Immediately re-engage the rope lock if the weight has been miscalculated.
Release the rope lock and gently lower each batten that you intend to work on. Shout "line coming in" or another warning to clear the stage as you slowly bring the batten in by pulling up on the purchase line. Engage the rope lock once the batten has been sufficiently lowered. Repeat for all battens requiring work.
Replace, move or suspend lighting, scenery and drops as needed, ensuring that each item has been safely attached to each batten. Calculate the new weight for each fly rail and remove or add weights to the arbor on the mid rail as needed.
Raise each batten by disengaging the rope lock on the fly rail and slowly pulling down on the purchase line until you reach the desired height. Mark this point on the purchase line with a small shoelace or other thin string.