From a 30 year freight Dog:
Cargo straps, as far as I know, have no regular checks, like a fuel control unit may have. They are inspected on a daily basis as used, much like a cargo container. Looking for tears, abrasions, rips, cuts...................
I have very high regard and respect for each of our loadmasters. Not that I don't go down and have a look see now and then, but I have never had a real problem with our loadmasters capabilities and performance.
Nylon Straps stretch, lets say that 100 pounds of tension was put on each strap.... and they relaxed to 50 pounds of tension. They still had a positive tension, forward, aft, up and down. even if the straps slacked off to neutral, the locking mechanisms would hold fast. If the load shifted,it might move a little whichever way, but the movement would not be shocking to the floor fittings due to the nylon stretching. Shock absorbers.
My questions are, the tie down loops on the vehicles, Were the edges sharp/ragged? Who did the cargo mod to the aircraft? Did they install the cargo restraint system properly? Was it previously over stressed somehow ?
I know from personal experience, that even during a tech stop,at minimum, the loadmaster, and one of the copilots take a little walk down stairs........ for a look see! Especially, on the SPECIAL LOADS.
This accident has made the cargo carriers second guess their procedures and SOP's to the NNNNNNth degree.
As sad as this is; hopefully we can learn something positive from this tragedy.