Originally Posted by Machinbird
The problem with the trim is that it moved to a high aircraft nose up setting without crew awareness.
Any pilot flying an aircraft with autotrim should know that his trim will follow his stick imputs, shouldn't he?
Originally Posted by Machinbird
It appears that a FBW aircraft requires the pilot to know exactly what mode the aircraft is operating in or else the question arises, "What's it doing now?"
Isn't it one of the basic skill needed for one wanting to be rated for a specific type? What makes you think that many FBW pilots don't know exactly in what mode their aircraft is operating?
Originally Posted by Machinbird
In the case of the AF447 crew, they had no attention to spare to consider what the trim might be doing
Well, considering that the trim was doing what a type rated PF asked, and what it is always supposed to do in such a case, what would be the point to consider that it would take more "attention" than usually?
Originally Posted by Machinbird
thus the nose up demands caused the trim to run silently to a high setting
Hence, as usual when imputs ask for a lot of nose up, what is wrong with that?
Originally Posted by Machinbird
without the knowledge or anticipation of the crew.
What make you believe that a type rated crew would not anticipate it or lacked the knowledge that it will do exactly that? Do you think that it wasn't what they wanted, nose up?
Originally Posted by Machinbird
Once at a high setting, the trim acted to stabilize the aircraft in the deep stall that they eventually achieved.
Right, the PF achieved a full stall with the help of the side stick, thrust and THS trim. Hence, what's wrong with the side stick, the thrust lever and the THS trim?
Originally Posted by Machinbird
When the Captain arrived on the flight deck, he had to puzzle out what he was seeing. From the jump seat, the indications were essentially hidden by the wheels themselves.
Beside hindsight, what makes you believe that the Captain would have immediately recovered the situation with all the trim settings displayed under his nose? He wasn't there from the begining of the crisis and still possibly far behind the other pilots. He also might have seen the Flight Control page, where the THS trim setting is displayed, right in front of him...
Originally Posted by Machinbird
The THS autotrim system has virtually eliminated the problem of trim-runaway, but it has replaced that problem with a new set of problems.
I still can see the problem with the THS trim. If they had acknowlegded their stalled situation in time, they would have immediately applied full and sustained nose down imputs, hence, THS trim would very likely follow that. If, for whatever reason, THS trim would not follow those imputs, not enough elvators authority should have attracted PF attention about considering that trimming nose down could help him... at least, theoretically if his training level wasn't the issue.