Nimbus 4 Accident

Roy Bourgeois a écrit :
My my own experience (32 years soaring , 2000 hrs, active
CFI-G) leads me to doubt that the pilot reaches for the dive brake while
plummeting down in a dive. More likely, he over stresses by a too dramatic
pull out during which an un commanded dive brake pop out occurs that
destroys the wing. Because of the location of the dive brakes on the
Nimbus 2 and 4 (they are quite far inboard) - this creates loads that would
not be found on a 15m ship pulling the same G load.

It is not unlikely that speed be very close to VNE increasing and in
such a case most pilots would extend the airbrakes if not all. That's
what airbrakes are for.

The wisest manouever in such case would be to extend the airbrakes as
soon as the glider is nose down, that would avoid the need for too much
g-load on recovery.

Note that in the case of an uncommanded pop out the airbrakes do *not*
increase the loads on the wing because they *decrease* the g-load - only
for the same g-load factor the wing root bending stress is increased.
Therefore, if there is a pop-up and the pilot does not pull more to get
the same g-load again, there should be no increased risk.

--
Denis

R. Parce que ça rompt le cours normal de la conversation !!!
Q. Pourquoi ne faut-il pas répondre au-dessus de la question ?