This dramatic highline failure in Lima, Peru looks like somebody tried to go bungee jumping while attached to a Stokes basket loaded with a (previously) uninjured victim.
A couple of points to note:
Just before the track line snaps, you can see the carriage kind of “chugging” along down the line, indicating that something is binding up somewhere. One thought is that the control line used to lower the rescue package down the trackline is on the downhill side of the carriage, which would cause the side cheeks of the pulley to dig into the rope until there was enough force to cause the pulley to move down the rope a bit before binding up again. Hence the chugging motion.
The tension on the trackline seems to be way too tight. While it is a sloping highline, there seems to be very little sag, which would indicate that the trackline was too tight and easily susceptible to being cut by something…like, say, a pulley that is loaded sideways.
There is no horizontal control line on the downhill side. When the basket falls, there is a substantial fall distance as well as one hell of a swing fall at the bottom of the ride. When the basket reaches the bottom of its arc, it starts to swing back up again, only to be stopped by the second floor walkway, which I’m sure did quite a number on the rope.
Had there been a lower horizontal control line, the total fall distance would most likely have been less, and the swing fall most certainly would have been all but eliminated.
Despite all of those things, the system still kept the load from hitting the ground. Not a ringing endorsement, but it does give you an idea of strong our equipment actually is.
I’d seen this video before, but Matt Hunt from Sterling Rope passed along a facebook link to it that caused me to search for a linkable version of it. Thanks for bringing it back to the forefront, Matt.
http://www.youtube.com/watch?v=unF2shRE2KY
And just for kicks, here is a dramatic presentation of what happens when there is not enough sag in the system between your anchors. It’s a good showing of the load pulling the anchors towards each other:
