W.J. (Bill) Dean (U.K.). wrote:

There were postings to Rec. Aviation Soaring when the report was published,
from pilots with experience of the Nimbus 4 and similar models who had
experience of inadvertent deployment of the airbrakes. If the brakes
deployed inadvertently while the pilots were recovering from the dive, this
surely may have been the reason for the amount of bending seen; and for the
overload which led to failure. Presumably those investigating the accident
were not aware of these incidents when writing the report.

If airbrakes deploy inadvertently, the first effect (along with the very
high drag) will be a *decrease* in G-loading *and* bending moment), both
due to the loss of lift near the airbrakes. The increase of bending
would happen only after the angle of attack has been further increased
(voluntarily or not) to restore the initial G-loading with more lift on
the outer panels (instead of the airbrakes section), hence the higher
bending.

Denis, you are very scathing.

That is not my intention... all I want is to give my opinion when I
think something is said here that may lead to dangerous flying - such as
sentences like "don't exceed VNE, but no problem if you exceed permitted
G-loading".

What do you think went wrong?

What would you have done?

Do you have any experience in the Nimbus 3 & 4 series? I don't.

Are you more experienced or better than the pilots who did not make it?

I don't know them and I would not pretend to be better (there are no
good pilots, only old pilots...). And although I have some experience in
Nimbus 4D (more on ASH 25) I never experienced a spin recovery and I
hope I never will have to. Therefore I don't know what I would do in
such a situation. All I can say is what I think (sitting comfortably in
my chair) is the better thing to do, as I said in a previous post :

"If your speed is going to exceed VNE within this manoeuvre [pulling
up], you should stop or reduce pulling and apply full airbrakes. At any
dive angle up to 45° this prevents the glider to exceeding VNE, and you
have time to recover pulling gently (under 2 g's). This of course
supposes that there is sufficient ground clearance... "



--
Denis

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