Having worked on both mobile and stationary cranes for nearly 15 years my question here is how/why did the operator allow the crane to pull the cable in that far? In my experience an emergency shutdown is designed to shut off EVERYTHING if something goes wrong, like say a function control sticks, etc and it will do it at ANY hook height. Now if your talking about the ATB (anti two block) switch that's designed to keep the block from getting pulled into the drum like happened here, that's a different story. In that case, it's true, it only works with the hook block at the top to pick up the weight. Even then the weight should be hanging far enough down to give the winch drum/line time to decelerate from speed and stop before the hook block gets sucked in.
That said, if it was a true emergency shutoff and not an ATB switch, why did any the function controls even have to be activated like they were to test it? If the emergency shutoff was activated, and if it worked, then once activated no function would work. In other words no power, no go, so no accident. This, in effect, would then prove that it did work.
Not knowing if your meaning a true emergency switch or if your meaning an ATB switch, I'll say this also. I don't know whether the crane has a winch speed control but if it did then it should have been being tested at a low speed. Even if it is a single speed control being activated manually (I assume it has no automatic function) the operator really should have no excuse for not paying attention and therefore not being able to release the function control before it sucked the block into the drum. To test under power he should have eased the line to the top and let it bump and slightly pick up the weight to activate the ATB switch and cut off the winch. If the line speed was too high for that to be done safely then the weight whould have been picked up in another "safe" manner to test the switch. Either way something simply wasn't right about this "test"
That said I agree with the heading of the post to never stand under a suspended load. In this case though there wasn't really a "suspended load" there was just the hook block which I'm sure gets walked under a million times a day. Granted getting under any load is not the safest place to be but there are times when it is a necessary evil in order to crib the load, cut off temporary bracing, etc. In the case of the hook block it's technically not considered a load and you pretty much have to get under it in order to rig a load...
Whatever the case, or load, the main thing is that that you use quality, tested cable and rigging, and have both an operator and, if needed, a signal man/men that know what they are doing. In the case of the snag breaking the strap, it sounds like the signal man/men wasn't properly watching the load in this instance...although I have been doing this long enough to know that occasionally $hit does happen..... As far as the cable breaking and droppng the hook block I think the fault for that can be placed squarely on the shoulders of the operator. Had he been either paying attention or simply using a little common sense to do the test safely that would have never happened.
Even though I don't really care for many of their tactics/policies myself, and whatever the final cause of this incident is judged to be, I'm sure OSHA will have a field day with their investigation. Good luck on that.
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