I had a hang gliding bridle not release from the tow. The problem was that I incorrectly attached the link to the tow line. These 3 pictures show the correct and incorrect attachments, and what happened when I messed up. The pics are from Pat Denevan.
This is how the tow link is supposed to look. It attaches from the pilot's bridle to the tow line.
I got the two white linkes reversed like this.
You can see that the loop that's through the grommet is quite long. Long enough so that it's going to get caught in the loop that it's holding. What should happen is that the short loop (through the grommet) runs out before the 2nd loop gets to the release point of the main loop. That didn't happen.
This shows what happened with the reversed the middle and short links, after I pulled the pin to release the tow line.
I'd used this bridle half a dozen times before, and had been careful with it. I just wasn't thinking this time. Bad idea when one's life, literally, hangs in the balance.