(1)An audible signal does not need to be sounded before lines are moved while grapple yarding if employees are not exposed to logs or rigging movement.
(2)Chokers must not be set when using a grapple yarding system during:
(a)Hours of darkness.
(b)Periods when visibility is reduced to such an extent that the yarder operator cannot clearly see the person setting the choker.
(3)One person carrying a whistle signaling device may use voice communications to transmit instructions and directions to the yarder operator when picking up an occasional log with a choker on a grapple yarding system only:
(a)During daylight hours.
(b)When the choker setter is in clear view of the yarder operator at all times.
(c)When all lines are slacked to the ground prior to the choker setter approaching the rigging.
(d)When all lines remain stable until the choker setter returns to a safe location away from any running lines.
(4)Standard yarding system whistle signals must be used when the choker setter is not in clear view of the yarder operator when chokers are set on grapple yarding systems. (See Appendix 7-A.)
Rule 437-007-0930 — Grapple Yarding,