3 ms·

The biggest advantage of the Boeing approach is that the controls are linked; if one moves, so does the other. Mismatched inputs are impossible. I truly don't

The biggest advantage of the Boeing approach is that the controls are linked; if one moves, so does the other. Mismatched inputs are impossible. I truly don't understand the Airbus approach... There is no method of resolving conflicts between the sticks that make sense... Sum them? Average them? Take the last seen input? Prefer the left side always?

mikekchar 10y ago
Not knowing anything about it, it seemed to me from the article that the system takes mismatched input as an indication that the autonomous systems need to be engaged. Though if it subsequently decides not to engage, I'm not sure what you should do...
fryguy 10y ago
I don't work in avionics, but in another field with two pilots. Most things are done by exclusive control meaning there is a selector for which station has the flight stick. But for shared control the way it works is the first station that has non-zero inputs takes exclusive control until they have zero inputs for a short period of time. Although in our case, the availability of two sticks is for hardware redundancy rather than pilot redundancy so the Boeing approach seems safer.
FabHK 10y ago
Of course there is a system, and it's sophisticated. Averages are taken in case of inputs on both, and there's a priority button to take precedence (so that the other is ignored). There's more to it than that, but of course there's a system and a lot of thought has gone into it. In the AF 447 case, the left pilot did take priority, but the dude on the right took it back. Had the left one taken it and held it (by keeping the button pressed), the accident might have been avoided. So the system is hardly foolproof, and one can argue about the particular implementation of the interface and the merits vis-a-vis hardware-linked yokes, but any notion that Airbus haven't thought carefully about it is complete bogus. http://aviation.stackexchange.com/questions/3455/why-is-the-priority-takeover-button-used http://aviation.stackexchange.com/questions/3455/why-is-the-...
- JshWright 10y ago
  I'm not saying it wasn't thought out, I'm saying that no amount of thought could result in a system that made sense in every situation... Having two independent control inputs means there is always room for subtle failure modes (either technical or operator related). Multi-master is a tricky problem to solve. When it comes to flying a plane, sitting here in my armchair, I think the the simpler solution (linked yokes) is likely the better one.
  - FabHK 10y ago
    Fair enough. I tend to agree, in particular as there was not only AF 447, but also the AirAsia from Surabaya to Singapore, Indonesia AirAsia Flight 8501, with basically the same failure mode. So: * KISS... but: * Airbus engineers are certainly aware of it, though... but: * they have thousands of Airbuses deployed out in the field though with the current tech, so it's unlikely to be changed anytime soon. Is even more training the answer? Dunno. My take: Today's jets are incredibly well designed and safe. If something goes wrong, though, still better to have rather competent crew sitting at the pointy end.

mikekchar 10y ago

Not knowing anything about it, it seemed to me from the article that the system takes mismatched input as an indication that the autonomous systems need to be engaged. Though if it subsequently decides not to engage, I'm not sure what you should do...

fryguy 10y ago

I don't work in avionics, but in another field with two pilots. Most things are done by exclusive control meaning there is a selector for which station has the flight stick. But for shared control the way it works is the first station that has non-zero inputs takes exclusive control until they have zero inputs for a short period of time. Although in our case, the availability of two sticks is for hardware redundancy rather than pilot redundancy so the Boeing approach seems safer.

FabHK 10y ago

Of course there is a system, and it's sophisticated. Averages are taken in case of inputs on both, and there's a priority button to take precedence (so that the other is ignored). There's more to it than that, but of course there's a system and a lot of thought has gone into it. In the AF 447 case, the left pilot did take priority, but the dude on the right took it back. Had the left one taken it and held it (by keeping the button pressed), the accident might have been avoided. So the system is hardly foolproof, and one can argue about the particular implementation of the interface and the merits vis-a-vis hardware-linked yokes, but any notion that Airbus haven't thought carefully about it is complete bogus. http://aviation.stackexchange.com/questions/3455/why-is-the-priority-takeover-button-used http://aviation.stackexchange.com/questions/3455/why-is-the-...

JshWright 10y ago
I'm not saying it wasn't thought out, I'm saying that no amount of thought could result in a system that made sense in every situation... Having two independent control inputs means there is always room for subtle failure modes (either technical or operator related). Multi-master is a tricky problem to solve. When it comes to flying a plane, sitting here in my armchair, I think the the simpler solution (linked yokes) is likely the better one.
- FabHK 10y ago
  Fair enough. I tend to agree, in particular as there was not only AF 447, but also the AirAsia from Surabaya to Singapore, Indonesia AirAsia Flight 8501, with basically the same failure mode. So: * KISS... but: * Airbus engineers are certainly aware of it, though... but: * they have thousands of Airbuses deployed out in the field though with the current tech, so it's unlikely to be changed anytime soon. Is even more training the answer? Dunno. My take: Today's jets are incredibly well designed and safe. If something goes wrong, though, still better to have rather competent crew sitting at the pointy end.