In normal law an Airbus doesn't stall with full back stick, that would just result in maximum AoA not a stall.

In this case it had degraded to loose some of those protections due to icing of the sensors.

That was confusing to the junior co-pilot, and they skipped basic procedures on who has control resulting in opposite inputs and a loss of control.

Yeah, I guess as someone who's had minimal instruction it seemed obvious. But reading the article it's clear that the junior FO was trained basically exclusively on the fly-by-wire Airbuses and probably didn't have that intuitive understanding when that protection was stripped away.

The plane in this case doesn't matter. No training for stalls ever tells you to pull up. It's directly opposed to how stalls ARE trained. This pilot was a chaos monkey, and the other pilots were unable or unwilling to get the chaos monkey out of the situation. He had completely reverted to human instinct, which is terrible for flying, and also was letting himself override his copilot, who was handling the situation much better.

People act like this situation wouldn't have happened had they had boeing style connected controls, but it's pretty likely that in this state, Bonin would have actively been wrestling with the controls to point the nose up in that state too. The only way to keep Bonin from killing everyone would have been to restrain him. There is no reliable way to "knock" someone out of that kind of panic state.

Perhaps the physical effort of struggling against his co-pilot would have made him realize he was doing something wrong. It's too easy to pull back full on a fully non-mechanical control, and just lock up there.

No, this situation is the same as when lifeguards are warned about saving panicking and drowning people, in that if you don't handle them in specific ways they will happily drown you in their panic. You cannot rely on "shaking someone out of it" in these circumstances because there is no reliable way to force the brain to reject it's panic instincts and return to rational thought.

The only solution would have been physical restraint. Bonin was an active threat

Locking him out of the controls would have been enough (if the technology allowed it). Even just relieving him of his duty would have been enough. If Captain Dubois had been there early enough and decided to relieve him, Bonin would have almost certainly obeyed.

If he doesn't, then I guess then you can resort to force.

Indeed. Other controls would have caused a wrestling match over the controls with probably the same outcome.

I believe the best solution is what Airbus implemented after this incident. An alert if there is dual input, and a button for the captain's side to override the other side. No need to wrestle, press the priority button and take over control.

Those existed before this accident. Bonin pressed the priority button to steal control from the other pilot, who was fixing things, at least once, and "dual input" alarms sounded pretty much the entire time the plane was falling out of the sky.

The ONLY way to have prevented Bonin from crashing the plane would have been to remove him from the controls. He was doing the same thing that lifeguards are warned about; when the human brain is in that kind of panic state, it will happily do things that it should know will inevitably lead to it's own death, like scrambling in such a way that you drown the lifeguard trying to rescue you.

With linked controls the captain would have instantly been able to tell what inputs the copilot was making and could have taken appropriate actions.

Aircraft UX should be made in such a way that there's never the slightest of doubts about something as fundamental to its function as where the inputs that its using are coming from.

But if you are in a stall at 35k feet, there is never a situation in which the corrective action is to pull up, especially not to max AoA. You aren't anywhere near the water, you should be trying to gain speed.

Bonin just went to primal instincts, full fight or flight, and was "taking matters into his own hands" even despite the fact that he was aware he wasn't doing anything useful. The other pilot even told him to stop, but he didn't. He wasn't a copilot in this scenario, but rather a direct adversary to recovery of the plane.

He should have been treated as a rogue pilot the second he started panicking, but the other guy was kinda busy. He was not acting rationally in any way. Had he dropped dead from a heart attack, AF447 would be an interesting anecdote instead of a tragedy.

How do you train pilots for: "In very rare cases, especially during a crisis, you may need to physically harm your coworker to prevent them from causing the death of hundreds of people, but definitely don't do it if you're the one causing the problem, which you will never figure out if you ARE the one causing the problem"

I have an instructor rating, part of training is exactly that. If someone freezes up at the wrong moment, be prepared to use violence to get them off the controls.

One trick that often works is to put your hand in front of their eyes. Humans have a deep instinct to want to see at all times, so they'll let go of the controls and use their hands to remove yours. No need for physical harm.

Bonin was showing himself to be extremely resilient to coming back to reality and rationality. He needed to be physically restrained. He was far too stuck in his head to rely on anything less.

Alternatively, we just kinda have an understanding that if your pilot goes into panic, and the copilot can't figure out a way to get them out of it, everyone dies.

Of course, then what if they panicking pilot decides they have to restrain you so they can continue what they are doing?