This is a fantastic question. I can think of no situation where this behavior would be desireable, but then again IANAP

I am a pilot (a small one but instrument rated) - there's no time EVER that you want that, and I am shocked the Airbus does not have a warning that says DUAL INPUT BEING RECEIVED. At the very least, it should give priority to the left seat controls.

Was really shocked to read the article.

It does: there's an audible warning that says the words "DUAL INPUT"

The English translation of the BEA's third interim report on the flight is available here: http://www.bea.aero/docspa/2009/f-cp090601e3.en/pdf/f-cp0906...

It includes the full CVR transcript at the end, which shows that the dual input alarm activated five times.

I think that part of the problem here is that the plane is so far out of trim and CRM has gone completely out of the window that psychologically at least the mental workload on the junior pilot has caused him to "freeze".

Far worse, imaging a situation where one of the control inputs fails; i.e. constantly produces nose up input. Can one of the inputs be suspended / turned off?

Then link the sticks mechanically.

Still, if the panicky guy is unconsciously trying to out-muscle you, well, then you reach over and punch him in the face.

If even that fails... uh... I guess you're in deep deep doo-doo at that point.

... so if there was a noise (intercom, radio, talking etc) and you didn't hear the announcement, that's it ,game over.

I'm a pilot and that seems insane.

IAAP (not commercial) and that sounds like an awful way to do things. An important aspect of cockpit resource management is to know who is controlling the airplanes, and part of that is always positively verbally transferring control, with confirmation. "I have the plane." "You have the plane." There is no situation where you want two people to both have input at the same time.

IIRC, that was lesson 1, minute 2 (right after take-off). The previous commenter who said that wouldn't think to ask because it is akin to asking 'is the computer plugged in' is probably right (though the captain should have noticed it when he was observing).

Serious design flaw, and tragic human error with devastating results. :(

I'm actually mildly surprised that it waited until you were in the air. I always brief that before takeoff whenever I take another pilot along. But yes, very basic stuff in any case, and amazing that they were not following this standard procedure.

Same experience. Pre-flight briefing with instructor: "When I say 'I have the plane', do NOT fly the plane".

But then again, that's a VFR flight in decent weather. I'd imagine it's a bit easier to get stressed in the middle of the night in a storm over the Atlantic with electrical failures.

I think another major difference is that in most planes, you can feel when the other guy is screwing around with the controls because they're connected, so you can yell at him to stop doing whatever he's doing.

It seems to me that it would be worthwhile to fake this in a pure fly-by-wire environment. The added cost and weight of a force-feedback system on the control sticks should be minimal compared to the aircraft as a whole.

Wouldn't be surprised if that's one of the outcomes of this - you'll still have the ability to override the other stick, but you'll know you're overriding.

I guess it could be a cheap workaround to always get smooth transitions when changing pilot. Imagine if one pilot holds full left and the other full right and you press a "switch now!"-button. You would need some kind of transition-period of maybe a second to avoid jerk which could be confusing for the pilot to not know when he has full control and when he is in transition.

This is likely the reason, and probably not just as a cheap work around, in most day to day situations it's probably the desired effect since both sticks are independent and don't move in reaction to the other.

Actually if both sticks are actually linked, the person taking over will find his stick already full-left, and have to actually pull it over to the right as part of "taking over". Such simplicity and it would result in none of this insanity.

good point - but I think a 'dual input' mode is the wrong solution to that problem.

Simply is the cheapest when you want to go all digital.

True. But, how would you want to handle the situation of two equally competent(at least in the eyes of the employer) co-pilots vying for control? should it always go to one? always go to the other? have a switch controlled? controlled by whom? not easy questions if you ask me.

edit: I actually can't think of a good way to do that other than have a manual switch on the console that would switch between the two controls. anything else seems amazingly bad.

perhaps have the plane decide which input seems more rational, then announce who has control.

Sounds like a great way to further mess up an emergency by making it harder for people to figure out the impacts of their actions on the situation.