Hi Robert,

You are right Robert. The glider is unaware of groundspeed.
Looked several times at the short film of the crash where it is
obvious that the DG500 is flying to slow relative to the fast moving
air rather then to slow relative to the ground while having a lot of
tailwind (which is not very fast either).


I showed the film to one of our airobatic pilots.
His comment was:
- the airflow may have been very turbulent at low altitude due to
several obstructions in the field
- at the last moment the pilot tried to line up the glider with the
runway or his selected landing spot and therefore applied a lot of
right rudder and some right stick input
- when he observed the right wingtip to get rather low he tried to
move it up using left stick input
- so then you had the classic spin inputs: low speed and crossed
controls
- the right wing stalled first because of the aileron deflection
downwards; the full rudder deflection to the right made it worse; a
spin became unavoidable.
- undisciplined glider pilot

Though my calculation of pitch down input during the 180° turn back
curve to the field was based on a wrong supposition (sorry for that)
it would have helped the pilot a lot to speed up his glider which
might have been just enough to make a safe landing. No excuse though.

Karel, NL