Le lundi 1 février 2016 20:01:27 UTC+1, Don Johnstone a écrit*:
At 18:23 01 February 2016, Ramy wrote:
There is a list of 7 accidents in the previous post due to loss of control.
Just over 8% of the total built have been lost to loss of control
accidents.
I wonder how many other people have to die or parachute to safety
before someone asks the question, should this glider be flying at all.

That's not totally true.
- Spain: wrong decision (turn back) after engine failure after take off
- Zapala: hitting the rocks at low altitude in turbulent blue thermal day

Vinon 2009 was actually loss of control in spiral dive, inexperienced crew.
Bitterwasser 2016, the future will tell (the crew is alive and is professional).
The others, I don't know.

These gliders cannot undergo a spin or a spiral dive without an almost certain fatal issue (in particular if they have an engine), unless you are an expert test pilot. I was forced to do that in an ASH25E twenty years ago and although I could stop the spin after less than a turn, the recovery was above Vne and the fuselage was over the vertical position (i.e. slightly negative). I said NEVER again!

In the case of the N4D, it happens that the airbrakes will self-open (photo available) during the pull-up due to both the high lift force and the kinematics of the control rod. No way to avoid loosing the outer wings. Amazingly, I have flown 2 500 hrs in my N4DM, almost at the maximum rear CG, and could never enter a involuntary spin, but twice the beginning of a spiral dive because the inexperienced pilot tried to recover using the opposite aileron and pulling, promptly recovered with stick in the middle and little forward, and full opposite rudder, exit at Vne.

Big ships are like this, if you don't like, don't buy!

All the best,
jmc