Several years ago in soaring magazine
there was an article about a glider kiting and the
tow pilot was unable to release. However the cause
was not that the schweizer release jammed, it was the
result of a poorly installed and secured release cable
housing. The cable ties used to secure the release
cable housing to the airframe failed, which then resulted
in excessive slack in the release cable. This excessive
slack meant that the tow pilots release handle was
incapable of pulling on the schweizer release lever.


Many years ago there were tests of Schwiezer releases that showed that
they did, indeed jam. These should all be replaced ASAP. Anyone with
a brain can look at a Schwiezer release and see why it will jam under
high loads.

2c