3 ms·

It's not something that can be changed on airbus cockpits, since the nature of side sticks makes them impossible to be mechanically linked, unless there was som

It's not something that can be changed on airbus cockpits, since the nature of side sticks makes them impossible to be mechanically linked, unless there was some very complex motor system built into each stick that provided force feedback equal in strength to a pilot tugging hard on it.

masklinn 3y ago
> unless there was some very complex motor system built into each stick that provided force feedback equal in strength to a pilot tugging hard on it It does not have to be “equal in strength to a pilot tugging hard on it” since there is normally no significant load applied by the stick to the hand (only the centering springs). So most every feedback should be noticeable. And force feedback is being deployed right now on commercial planes. The Irkut MC-21 was supposed to be the first airliner featuring them, but the invasion of ukraine and subsequent sanctions nixed that (as the provider of the sticks is the french company Ratier-Figeac). Gulfstream’s 7th gen (GVII) also have active sticks, provided by BAE.
- MichaelZuo 3y ago
  Yes, but then no one would consider the feedback to be the equivalent of a mechanically linked system, like what Boeing uses.
  - masklinn 3y ago
    Of course they would: the problem is that there is a lack of feedback when incompatible input is entered. Audio feedback was added since AF 447 but as well known sound is one of the first thing to be blanked out in high stress situations. Physical feedback provides a second stimulus, and one which does not get ignored as much. The planes are FBW, the side sticks have no mechanical linkage outside their control box, there is no cause for a pilot to input significant force on the stick, and thus most every feedback would be sensible. Unlike a 737, the pilots are not physically moving the control surfaces.
    - MichaelZuo 3y ago
      The moment one pilot does tug hard on the stick though, then the same problem is still there. So it will work most of the time except when you really need to, when the other pilot is panicking and won't provide accurate answers.
      - masklinn 3y ago
        > The moment one pilot does tug hard on the stick though, then the same problem is still there. No, because the point is that the other pilot will feel the action and thus know that there are conflicting input. The sticks can even synchronise their movements, that way pilots can both see and feel that their copilot is inputting. That is the point, making the existence of conflicting input clearer. > So it will work most of the time except when you really need to No. > when the other pilot is panicking and won't provide accurate answers. The sticks support taking priority, so a pilot seeing that their copilot is panic-inputting would be trained to press and hold the priority takeover button, deactivating their copilot’s stick.
        MichaelZuo 3y ago
        You seem to be confused, obviously it won't work 100% of the time due to shear probability, it's not physically linked up so there will always be a possibility of one or both pilots ignoring every possible warning, shaking, vibration, mild pushback, etc... regardless of how well they've been trained on detecting these. Whether it works the vast majority of the time, in practical situations, remains to be seen. Confusing a known, physically guaranteed, aspect of a system with an estimated likelihood of actual system performance is a common mistake. Even with the most ideal deployment scenario, assuming it does get widely deployed one day, the real world performance reliability will likely not get anywhere near six sigma, let alone 100%.
hn8305823 3y ago
The Cirrus SR-22 (the best selling general aviation plane every year since 2003) has mechanically linked side sticks. They aren't fly by wire like the Airbus but it shows they can be linked without a complex motor system.
- rootusrootus 3y ago
  > Cirrus SR-22 Are those really side sticks, though? They look much more like one half a yoke than the kind of side stick you'd see in, for example, an Airbus or an F-16.
rbanffy 3y ago
> It's not something that can be changed on airbus cockpits You'd need to run cables between them and redesign the sticks to have mechanical hooks, and it'd be a very ugly hack, but it's hardly impossible.
- MichaelZuo 3y ago
  Impossible for it to still be viable for a commercial airliner competing on costs, especially long term upkeep costs. Not impossible for an unlimited budget.
  - rbanffy 3y ago
    I think the biggest no-nos on this hack would be that it'd need to be certified and since it fundamentally changes the UI for the pilots, everyone would need to be retrained. The hack itself would be a small detail line on the overall budget for the changes.
    - masklinn 3y ago
      The retraining would barely be a concern. It would be a new input similar (but not identical) to the stick shaker, or a new audio alert (as was literally introduced for the dual-input issue after AF447). The hack is the entirety of the cost, it would require completely redesigning the side-stick, updating their entire maintenance procedure (currently side-stick can trivially be unscrewed and swapped out), as well as redesigning the cabin cell to provide routing for the cables such that they keep tension and don't get damaged. Stick manufacturers have been working on active sticks for more than two decades, and they're getting released right now. While force feedback on PC joysticks was introduced in 1997.
  - deleted 3y ago
    [deleted]
KennyBlanken 3y ago
...it's a spring and a servo. Or a brushless motor. https://github.com/scottbez1/smartknob https://github.com/scottbez1/smartknob ...or any not-bottom-end-of-market steering wheel for driving video games.
- outworlder 3y ago
  It's not just "a spring and a servo" when we are talking about aviation. Redesigning GA aircraft and rectifying is already bad enough. An airliner, and something as crucial as flight controls? Yeah, good luck jury rigging some servos.
cco 3y ago
I believe Airbus is planning to add force feedback to the side sticks for this error case. But I don't know that. Many aircraft controls already have force feedback in the form of stick pushers [1], a device to violently shake the control yoke when the aircraft is at risk of stalling. Those have been around since the 60's. So this is not only possible, but it's been around for a long time though Airbus had chosen to use a verbal warning only instead of a stick shaker.
thescriptkiddie 3y ago
is there really no mechanical connection between the stick and the control surfaces on an airbus? that seems really dangerous.
- jaywalk 3y ago
  There really is no mechanical connection. And the Airbus A320 (first airliner with no mechanical backup) has been flying this way since 1988, so it's not anywhere near as dangerous as you think.

masklinn 3y ago

> unless there was some very complex motor system built into each stick that provided force feedback equal in strength to a pilot tugging hard on it It does not have to be “equal in strength to a pilot tugging hard on it” since there is normally no significant load applied by the stick to the hand (only the centering springs). So most every feedback should be noticeable. And force feedback is being deployed right now on commercial planes. The Irkut MC-21 was supposed to be the first airliner featuring them, but the invasion of ukraine and subsequent sanctions nixed that (as the provider of the sticks is the french company Ratier-Figeac). Gulfstream’s 7th gen (GVII) also have active sticks, provided by BAE.

MichaelZuo 3y ago
Yes, but then no one would consider the feedback to be the equivalent of a mechanically linked system, like what Boeing uses.
- masklinn 3y ago
  Of course they would: the problem is that there is a lack of feedback when incompatible input is entered. Audio feedback was added since AF 447 but as well known sound is one of the first thing to be blanked out in high stress situations. Physical feedback provides a second stimulus, and one which does not get ignored as much. The planes are FBW, the side sticks have no mechanical linkage outside their control box, there is no cause for a pilot to input significant force on the stick, and thus most every feedback would be sensible. Unlike a 737, the pilots are not physically moving the control surfaces.
  - MichaelZuo 3y ago
    The moment one pilot does tug hard on the stick though, then the same problem is still there. So it will work most of the time except when you really need to, when the other pilot is panicking and won't provide accurate answers.
    - masklinn 3y ago
      > The moment one pilot does tug hard on the stick though, then the same problem is still there. No, because the point is that the other pilot will feel the action and thus know that there are conflicting input. The sticks can even synchronise their movements, that way pilots can both see and feel that their copilot is inputting. That is the point, making the existence of conflicting input clearer. > So it will work most of the time except when you really need to No. > when the other pilot is panicking and won't provide accurate answers. The sticks support taking priority, so a pilot seeing that their copilot is panic-inputting would be trained to press and hold the priority takeover button, deactivating their copilot’s stick.
      - MichaelZuo 3y ago
        You seem to be confused, obviously it won't work 100% of the time due to shear probability, it's not physically linked up so there will always be a possibility of one or both pilots ignoring every possible warning, shaking, vibration, mild pushback, etc... regardless of how well they've been trained on detecting these. Whether it works the vast majority of the time, in practical situations, remains to be seen. Confusing a known, physically guaranteed, aspect of a system with an estimated likelihood of actual system performance is a common mistake. Even with the most ideal deployment scenario, assuming it does get widely deployed one day, the real world performance reliability will likely not get anywhere near six sigma, let alone 100%.

hn8305823 3y ago

The Cirrus SR-22 (the best selling general aviation plane every year since 2003) has mechanically linked side sticks. They aren't fly by wire like the Airbus but it shows they can be linked without a complex motor system.

rootusrootus 3y ago
> Cirrus SR-22 Are those really side sticks, though? They look much more like one half a yoke than the kind of side stick you'd see in, for example, an Airbus or an F-16.

rbanffy 3y ago

> It's not something that can be changed on airbus cockpits You'd need to run cables between them and redesign the sticks to have mechanical hooks, and it'd be a very ugly hack, but it's hardly impossible.

MichaelZuo 3y ago
Impossible for it to still be viable for a commercial airliner competing on costs, especially long term upkeep costs. Not impossible for an unlimited budget.
- rbanffy 3y ago
  I think the biggest no-nos on this hack would be that it'd need to be certified and since it fundamentally changes the UI for the pilots, everyone would need to be retrained. The hack itself would be a small detail line on the overall budget for the changes.
  - masklinn 3y ago
    The retraining would barely be a concern. It would be a new input similar (but not identical) to the stick shaker, or a new audio alert (as was literally introduced for the dual-input issue after AF447). The hack is the entirety of the cost, it would require completely redesigning the side-stick, updating their entire maintenance procedure (currently side-stick can trivially be unscrewed and swapped out), as well as redesigning the cabin cell to provide routing for the cables such that they keep tension and don't get damaged. Stick manufacturers have been working on active sticks for more than two decades, and they're getting released right now. While force feedback on PC joysticks was introduced in 1997.
- deleted 3y ago
  [deleted]

KennyBlanken 3y ago

...it's a spring and a servo. Or a brushless motor. https://github.com/scottbez1/smartknob https://github.com/scottbez1/smartknob ...or any not-bottom-end-of-market steering wheel for driving video games.

outworlder 3y ago
It's not just "a spring and a servo" when we are talking about aviation. Redesigning GA aircraft and rectifying is already bad enough. An airliner, and something as crucial as flight controls? Yeah, good luck jury rigging some servos.

cco 3y ago

I believe Airbus is planning to add force feedback to the side sticks for this error case. But I don't know that. Many aircraft controls already have force feedback in the form of stick pushers [1], a device to violently shake the control yoke when the aircraft is at risk of stalling. Those have been around since the 60's. So this is not only possible, but it's been around for a long time though Airbus had chosen to use a verbal warning only instead of a stick shaker.

thescriptkiddie 3y ago

is there really no mechanical connection between the stick and the control surfaces on an airbus? that seems really dangerous.

jaywalk 3y ago
There really is no mechanical connection. And the Airbus A320 (first airliner with no mechanical backup) has been flying this way since 1988, so it's not anywhere near as dangerous as you think.