The Blackhawk tie down is about the same shape size as a regular caribiner, not a
d-ring. The top end is cut out and a blade fitting is put in so that it swivels back and forth. The blade fitting has a two part pin that fits into a corresponding point in the blade. the rope is tied to this fotting and to the a/c tie dowm rings. I'm SURE that this clears everything up
. Hopefully someone will be able to post a picture so that you can see how the tie down works.
Mac