|Quoting garpd (Reply 2):|
and would have corrected his actions.
Your reasoning, and that of the article, seems to be
- PNF did not react to the situation (did not push the SS
forward) [observation O1]
- If he had seen the stick being held back by PF
he would have understood the problem. That's totally obvious ! [Hypothesis H1]
From O1 and H1, we deduce that PNF did not know what PF
was doing [conclusion C1]
- The **only** way a PNF can know what commands a PF
is giving is to observe his stick movements [Hypothesis H2
- On Airbus that is not possible because of non-coupled sticks [Hypothesis H3]
From C1, H2
and H3, you deduce that the Airbus cockpit architecture prevented PNF from reacting : he could not see the other side, so could not possibly know what was going on, and so could not realize what he had to do.
Therefore the Airbus cockpit ergonomy contributed to the crash. QED
However I see all 3 hypotheses as questionable:
# H3 (not being able to observe the other SS
) might be true, but see PGNCS’ post in reply 8. It’s not as clear-cut as “you can’t see anything of what the other pilot is doing”.
(you can **only** observe control inputs by observing the other SS
) is the main point of misunderstanding behind all the arguments about the A cockpit. It is crucial here to understand that the control devices of a FBW aircraft are fundamentally different from those in a non FBW airplane.
In a none FBW, the pilot controls directly the surfaces, which are only indirectly linked to attitude etc…through the airplane’s dynamics. More simply, there is no direct transposition between what you see (instruments) and what you command (controls).
On FBW aircraft the computers take care of this "translation" for the pilot, and so the controls are actually directly linked to the aircraft attitude, speed etc…. Which means that the pilot can directly “see” what commands are being input into the system simply by looking at the PFD.
Caveat : once the plane was waaaaay outside its envelope that did quite not hold true anymore, because the plane could physically not obey the commands of the pilot. But it was true for a relatively long time into the accident.
# H1 is the hypothesis I would be most careful with. I just don’t think one can consider as “obvious” that PNF would have seen a yoke movement, immediately shouted Eureka ! and reacted correctly to save the day.
I mean, you could state as “obvious” that any pilot flying at 35 000 ft would b every careful about the possibility of stalling if the plane suddenly climbs 3000ft with no additional thrust.
And yet, it seems it isn’t that obvious...
Actually nothing is very obvious here. Because we simply don’t know what the pilots were thinking and so why they acted as they did.
Just for the PNF :
He waited 30 seconds before reacting to the initial climb and ordering the PF
to descend. Why wait so long ?
Why did he concentrate on calling the captain, instead of helping the PF
fly the plane (procedures, suggestions) ?
Why did he never ask the PF
to explain clearly what he was trying to do ?
Why did he not react at all to the stall warning ?
Why did he wait so long before trying to do something with the controls ?
Why did he not suggest anything, and instead made a short and feeble attempt to take over the controls ?
And so on…
I think the AF447 discussions always come back to the same thing : we need to know what was going on inside the pilots’ minds if we are to make any definitive conclusions. About Airbus ergonomic choices, or about anything else. But for that, you need to gather experts in psychology, ergonomics, flight ops, and aircraft systems …
Oh wait, that rings a bell…
What did the BEA decide to do ?
Conclusion : the final report should be interesting !