mattm wrote:
However, I will point out that a student pilot's actions are
considered
to be up to the instructor's judgement, even if the student is flying
solo. The instructor must have suitably trained the student to handle
the flight before turning them loose, and must supervise all their
flights
until their checkride. I think that's part of the NTSB attitude in
the
report, although they don't mention the instructor.

I know the instructor (and I knew the tow pilot and have met the glider
pilot.) The CFIG in fact had flown three flights with me while I was a
glider student. Of the three CFIGs in the club I flew with, he provided the
most detailed feedback and critiques. In fact whereas my primary instructor
considered me ready for solo, but had to travel on the weekend I hoped to
solo, he stepped in and flew three flights with me. But he did not sign me
off for solo. So I would judge his standards higher than the average CFIG
(he happens to be chief pilot for a businesss and pilots a company King Air
for them.)