This is a very bad design - at a bare minimum an incredibly loud and annoying alarm should go off if the pilots are fighting controls, because neither knows what the plane is receiving as an input.
You can see it used here: https://youtube.com/shorts/nBmPXrBpp3Y
You hear the normal 50.. 30.. etc. callouts and then when the captain goes full thrust you hear "priority left" which is the override button being pressed to pitch for go-around.
That's much nicer than what we have teaching with traditional controls. Because at that point overpowering a startled pilot is a bit hard.
FDR visualization: https://www.youtube.com/watch?v=0a06A78iXnQ
Interesting that the FO flying from the left seat did not recognise that callout as a big thing to react to.
(Unless you manage to hit the priority button for 40 seconds - but I assume that's for locking out a broken stick that's doing inputs at rest)
It's a bit different for a training captain like in the video. They know these are the first officer's first landings on the real aircraft, so when things go wrong they take over.
Section 6
> When a dual input situation is detected, the two green priority lights located on the cockpit front panel flash simultaneously.
> After the visual indication has been triggered, a synthetic voice “DUAL INPUT” comes up every 5 sec, as long as the dual input condition persists.
According to Wikipedia, this warning system worked as intended:
> Confused, Bonin exclaimed, "I don't have control of the airplane any more now", and two seconds later, "I don't have control of the airplane at all!"[42] Robert responded to this by saying, "controls to the left", and took over control of the aircraft.[83][44]
> He pushed his side-stick forward to lower the nose and recover from the stall; however, Bonin was still pulling his side-stick back. The inputs cancelled each other out and triggered an audible "dual input" warning.
> ...
> Bonin heard this and replied, "But I've been at maximum nose-up for a while!" When Captain Dubois heard this, he realized Bonin was causing the stall, and shouted, "No no no, don't climb! No No No!"[85][44]
> When Robert heard this, he told Bonin to give him control of the airplane.[2] In response to this, Bonin temporarily gave the controls to Robert.[44][85][2] Robert pushed his side-stick forward to try to regain lift for the airplane to exit the stall. However, the aircraft was too low to recover from the stall. Shortly thereafter, the ground proximity warning system sounded an alarm, warning the crew about the aircraft's imminent crash with the ocean.
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.
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.
The only solution would have been physical restraint. Bonin was an active threat
If he doesn't, then I guess then you can resort to force.
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.
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.
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.
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"
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.
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?
here is the story - https://en.wikipedia.org/wiki/Disappearance_of_Frederick_Val...
American 587 is another example where, in response to normal wake turbulence, the pilot mashed the rudder back and forth so hard it broke the stabilizer.
There is an airspeed, called maneuvering speed (Va), at or below which it should not be possible to use the flight controls to remove parts of the aircraft. (The aircraft should run out of control authority or stall prior to exceeding any load limits [which is well before the removal of parts].) Every student pilot is taught this prior to passing their first knowledge test and checkride.
The problem with that is the certification rules for Va are for a single input, not for a cyclically reversing sequence of inputs (which is what the first officer of AA 587 did).
As the details became clear, this was a big topic of learning for many pilots, including myself. AA 587 was caused by the flight crew, but I don't put it into the "insane pilot error" category.
This is factually incorrect.
If you read the Final Report you will see that the FP1 (the one that have placed the abnormal inputs in the side stick) did not had the appropriate training; actually the scenario that happen has not even in the trainings (Nightly mid-atlantic flight with screen disagreement with one of the FP missing that I’m normal law).
At least for me, this accident was one of the top 3 most important in terms of safety measures and changes in aviation because the entire industry needed to think about the role of automation, training design, cockpit design, etc.
Two possible reasons in this case.
1) Bonin might not have understood he was in full manual control, and that the computer was no longer restricting his pitch up command to the maximum advisable pitch.
2) The stall warning was intermittent on the way down, because it turns off below a certain air speed. Of course, low air speed contributes to stalling. They were stalling the whole time, but ironically as they started to gain air speed (a good thing) the stall warning would kick in because it was no longer below the lower limit for a stall warning.
Also there's the ever present reason of panic, brain-lock, confusion, etc.
In this case, ultimately, the pilot and the co-pilot were exerting opposite controls. One to pull up, one to push the nose down. In a stall you push the nose down to gain aerodynamic lift. That's like Flying 101. But I guess when you panic, the natural instinct of wanting to pull up kicks in when you're rapidly losing altitude. Still, training?
I saw another one the other day: Ethiopian Air Flight 961 [1] from 1996. This accidently ultimately came down to a single switch being on: manual cabin pressurization. This was on because a pilot reported an error in a previous flight and maintenance were trying to replicate it. The pilots (and passengers) passed out from hypoxia and didn't put on their oxygen masks. Again, not putting on your mask? Pretty basic. Also, Flying 101. If you lose (or don't have) pressurization, drop your altitutde. You get below 8000 feet and you're fine.
There was an error but it wasn't ignored and it wasn't entirely obvious, causing revisions to be made. Also, hypoxia can impair judgement very quickly. But why keep climbing when something is wrong?
[1]: https://en.wikipedia.org/wiki/Ethiopian_Airlines_Flight_961