What might cause a tear to an internal rib?
If you drop your glider on the leading edge, closing off the ports, the weight and momentum can create enough pressure inside to separate the top and bottom surfaces. The damage is not always apparent. On a lot of the rib repairs I do the pilot did not know that it was damaged until another pilot noticed a bulge in the glider. If you beak your glider and it makes that characteristic WHOOMP sound, you should check inside for center and V-rib damage.
