On Tuesday, October 16, 2018 at 6:38:55 PM UTC-7, son_of_flubber wrote:
True story. A couple years ago I ran the wing for a glider that aerotowed into rotor. The rope broke. Both aircraft and both tost rings made it back to the airfield. The rope broke at both ends.

How is that even possible?

That's an interesting puzzle. Here's one way of thinking about it that makes it seem possible...

Polymers are not purely elastic. They have a dynamic modulus. That is to say that stress and strain are not communicated instantaneously. There is effectively a time constant of propagation down the rope. So assuming that the tension in the rope is steeply rising before a break occurs, and assuming that the strength of the rope is pretty well balanced between the two ends; then as the weak end breaks first, the tension at the far end will still be rising for a short period of time while the message is in transit that the rope has already broken. During that propagation interval, the strong end breaks as well as it was only slightly stronger than the weak end. Or, in the limit, the two ends were busy breaking at the same time and neither end knew anything about the trouble at the other end of the rope since the two ends are isolated by the mechanism of the dynamic modulus.