In reply to druss:
> Thanks. I'm familiar with that setup but sometimes the situation is more suited to create a equalised anchor using slings/cordlette and tieing the ab rope using a figure of eight (purple rope) like at the link below.
> Instead of the fig 8 in the above picture, can you use an alpine butterfly instead with a tied-off tail (no tension)?
The Alpine Butterfly is easier to untie when rigged as per other's have mentioned - a Y hang, where the loop and a leg/strand are both loaded. Your suggestion of just using the loop with the leg/strand tied off (to what, if not an anchor forming a Y hang?) would end up being just as uneasy to untie.
If what you're after is a loop knot, that is easy to untie after being weighted, then the standard response would be figure of nine loop.
There is load data for the AB when used as an end loop. It's less strong than a figure of eight loop. (It won't break but some people get wound up about such stuff).
Post edited at 19:46