Originally Posted by
HazelNuts39
Altitude variations affect IAS via the static ports. "Turbulent air" as such does not.
This may not be apparent as the output of the altitude calculation from the statis prerssure to the altimeter is filtered, but I assure you that it does.
Mach buffet is a violent high frequency shake of the aircraft that is very different from turbulence-induced g-variations. The airplane had left the turbulence before it stalled.
I am talking about the stall buffet. The aircraft was at that point flying too slowly to induce a mach buffet
Once stalled, the airplane is effectively uncontrollable in roll, its reponse to a roll input is often opposite to that commanded, at any rate quite different from normal.
There is most definitely a degree of residual positive roll control in an aircraft of conventional design when deep stalled. How much exactly for a particular aircraft in a particular circumstance is a question nobody can answer for sure as this has to my knowledge never been tried in a large aircraft (and lived through), but the windtunnel data, flight test data and computer models which are used in the aerodynamic models in simulators leave little room for doubt. I will concede however, that this is way beyond what any sim is certified for for flight training.
Originally Posted by
AlphaZuluRomeo
No. In Alternate 2 law, roll is direct. Meaning sidestick deflection gives proportionnal control surfaces deflection. This is different than the normal mode, and FBW doesn't try anything here, no "masking".
Fair enough, it seems I had my modes mixed up.
What flight are you talking about
If still AF447 : sorry, this one never get to overspeed.
Same question. If that's AF447, I fail to see anything suggesting any of the crew members ever understood the stall situation.
Have you read the CVR transcipt?
Two remarks:
- It still remain to be proved that elevators only aren't enough to maintain stall (at a lower AoA than that obtained with the help of the THS, maybe). IIRC knowledgeable peope (of which I'm not) suggested otherwise.
My point was that with elevators alone the aircraft will drop the nose again when the elevator backpressure is released, but this may no longer be the case when the THS is trimmed fully aft.
- What do you mean by "the lack of autotrim on Boeings"?
I know of no Boeing type which has an Airbus type autotrim system that automatically trims the THS to relieve pitch input. In manual flight, even the 777 and 787 have to be trimmed manually for airspeed using the trim switches. This does not take into account some functions where the trim is adjusted automatically with flap and speedbrake deployment, but the fact remains that the pilot is almost completely out of the loop with regards to the THS in the Airbus.