Janos Bauer wrote:

What are the standards altitudes for such incident? Here are the list
I learnt: 50 straight landing, 50&100 one 180 degree turn, 180 two
turns or small circle. Of course in strong wind I would increase these
values.

I have been VERY surprised a few times by the effect of a slight
tailwind on my rope break practice. Since then I pay a lot
more attention to when the towplane rotates. If he rotates
much further down the strip, then I know I have either
a tailwind, heavy glider, high density altitude, etc.

Of course this assumes the towplane pilot rotates at the same speed
each time (in my experience they are very consistent).

In the cases when this happens
I know we ain't doin' very much "up" for the amount
"forward." So I SWAG a higher 180 altitude (maybe 300 or 400 feet).
The worst was an open canopy L-13 with two people on a hot
day with a 3-5 knot tailwind and only 180hp towplane. I dunno
if even 400 feet AGL woulda been enough.

Anybody else use the point of towplane rotation as
a hint?

I've wondered why airliners don't have some spot on the
ground (GPS) some distance down the runway, and abort
at that spot if they haven't reached a certain airspeed.
Seems simpler than doing all them calculamications for
wind, density altitude, etc. which may have changed since
you did them. Why not observe instead of predicting?

It doesn't work if you have ice/frost on the wings,
or if the ASI malfunctions (reads too high AS),
or you're misconfigured, but otherwise it seems to make
sense to me...

Of course when's the last time anybody de-iced a towplane or
glider, for goodness sakes! ;O