Accident to Education: Dangers of Side Pull


When we educate new mobile crane operators, one of the many topics we cover is the importance of lifting from directly above the load’s center of gravity.  However, it’s easy to forget until something goes wrong.

So why does this sheave look like this?

In the case of this sheave, which was taken from a rough terrain telescopic boom crane, it shows severe damage not just to the flange of the sheave, but to the outside of the sheave as well. Not only did the operator side pull the load crane once or just a little bit, the operator had to side pull enough to bend the wire rope keeper so that the wire rope could jump off the sheave.

Now instead of working around the proper D/d ratio of the sheave, the rope was bending over the sheave pin and causing severe damage there too.  The interesting part is that when you look at this sheave closer not only does one side have damage, the other side shows the same shearing effect.   Meaning at some point after the wire rope jumped the sheave, it was discovered and placed back onto the sheave. At that time, not only should the sheave been replaced, maybe it should have been asked why is this happening?  But this question was either not asked or the operator didn’t know the importance of this damage.

Not only did the operator continue to run the crane after the rope was re-reeved, they continued to operate it improperly as the rope jumped off the sheave again. This caused the damage on the other side of the sheave.

Unfortunately, there was a fatality at this location. During the accident investigation, it was determined that the leading cause was due to operator error and lack of proper training. During the operator training that occurred after the incident, an impassioned operator stated, “if we’d only known about the dangers of side loading, our co-worker would be here today.” His reasoning was sound, as shows the importance of having properly trained and qualified operators running equipment to keep your site safe.

Remember, Safety through Education is more than just Crane Tech’s motto it is our guiding principle. If we can help with your training needs for qualified or certified operators, whether on mobile or overhead cranes we are here for you.  We have both open enrollment courses, which are cost effective for a couple of operators, or on-site training for your entire crew.


Previous Posts in the Accident to Education Series

Third Times A Charm

Small Loads Can Cause Tipping

Plate Clamp Safety


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