Originally Posted by
bearfoil
(Of course "Flight" can only be used advisedly, the BEA concludes accelerations and velocities that preclude this a/c from "flight").
As far as I can see they've stopped using "flight" in that context in the second report - very likely because it wasn't understood. It was a translation of the french that may make more sense in conext in that language, but didn't in english.
As efficiently as the VS was designed, it wasn't meant to survive much vertical acceleration of any description, only side forces. So on the one hand, its strength to weight ratio defines the engineering consideration, and the architecture of the three joins. Sudden decelaration in a vertical manner suggests that the VS would be driven into its mounts, not "pulled away".
Agreed, but the VS
was driven into the forward mount,
and there was other evidence of sudden vertical acceleration - vertical load pickup arm showing large loads "in the rudder hinge axis".
To think that the VS/Rudder "rolled forward" around its forward attachment, after the aft two were sheared, is a challenge; the forward velocity was not high (?).
There would be a sudden pitch down in the event of a tail-first imapct though ?
Possible. At .83 Mach an upset in Pitch caused by high speed Stall would be followed by an almost certain wing drop, resultant Roll, and then Yaw. It isn't necessary to consider a control input to have been the cause of catastrophic failure of the VS/Rudder. Any upset at this a/s would be a bag of snakes, it is highly likely that more than one attitude would be out of limits, not just Pitch.
Agreed, and I agree that structural failure of VS and/or other parts of the a/c would be quite possible in that event.
However, I don't see how you are going to generate the large force through the rudder hinge axis in that case. I was also going to hold-up lack of depressurisation - but having looked again I think that we don't have a fuselage forward of the aft bulkhead ripped out with the VS (as in I think one attachment
is forward of the bulkhead, but it is not still attached to the VS).
We know what an airbus VS ripped off by side loads looks like (587) - and I don't think this one matches up. Also, this one was found with other wreckage, wheras if it separated before impact I'd expect to find it some way back along the track (although I do appreciate that it
could separate during an upset in which most horizontal speed has been lost).
We also know that the VS
can separate during impact with water -(XL in the Med - BEA probably still have that one to compare).