http://home.nps.gov/applications/digest/...larea=incidents

Report from the NPS on the accident

Doesn't really add much.

Supposedly the story from Supertopo is that he used to girth hitch the slings his aiders were attached to directly to his belay loop instead of through his tie-in points. A girth hitch is the sharpest knot we use. Jugging is the hardest, most regular bouncing we do. It's not hard to see how that would wear through your belay loop over time.

I'm willing to accept that as an answer to "how does something infalliable fail?"

Forget about this.

Burying your head in the sand is about the saddest reaction I've seen so far. What's the point of discussing the causes of an accident, if at the end you arrive at "won't happen to me, don't think about it, la la la" denial? Sometimes it seems that's almost the goal - to find a reason to dismiss an accident as "couldn't happen to me!"

There are several worthwhile take-home messages from this thread:

Belay loops rarely fail, but do require a second glance every now and then.

Most cavers will hold backups above the device open, but it is an unresolved issue for backups below the device and for whether this depends on users' experience level with the backup.

Backups clipped to a leg loop may rip that loop apart (I suspect this depends on the type of leg loop - buckle vs. stitched, one-piece vs. independent loops).

Girth hitches can break Dyneema. Girth hitched daisies can fix your belay loop in place, possibly causing accelerated wear in a less noticable place.

Replace slings when they need it. Soft goods wear out, period end.

Just because the accident investigation didn't arrive at "abandon your belay loops!" doesn't translate into "forget aobut it" for me.

Did you change the batteries in your smoke detector last week?

Recent tests on joining two slings together, from Kolin Powick at BD:

http://www.bdel.com/scene/beta/qc_kp.php

Because local code requires it, my smoke detectors are hard-wired. But thanks for your concern.

I thought even the hard-wired ones had battery backup. What happens if the electricity is out?