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Don't airplanes have an equivalent of 'power steering' like we have in cars? It seems strange that pilots have to use actual physical force to move the control

Don't airplanes have an equivalent of 'power steering' like we have in cars? It seems strange that pilots have to use actual physical force to move the control surfaces, and that there is a point where the physical force of a human is not enough anymore to move them. I get that Boeing wants to give pilots feedback of what is going on in and around the airplane. But putting pilots into a situation where they can't command the airplane even if they want to is a bit extreme.

tomglynch 7y ago
> putting pilots into a situation where they can't command the airplane even if they want to is a bit extreme. I agree, this is the main issue. In both cases if pilots had a clear option to just switch off MCAS we would have not lost over 500 lives.
- gok 7y ago
  Unlikely. In the case of the first crash, they didn't even get as far as switching off the stab trim (they were flipping through the flight manual to find it as the plane crashed). A second switch would have done nothing if they couldn't remember how to use the first one. Yet another switch in a cockpit (which already has hundreds of them) would also have been yet another way to create an emergency by having a switch accidentally flipped the wrong way. In an emergency it has repeatedly been shown that pilots often forget complicated/rare recovery procedures. We need to stop relying on humans to perform at a superhuman level in these situations; better automation is the only way out.
  - infecto 7y ago
    Better automation like MCAS?
  - zubspace 7y ago
    On the other hand, there are many who believe, that automation got us into this. The more we automate, the more we depend on it which leads to problems if exceptional situations occur. [1] Maybe the 737 Max is just too complex and relies too much on automation to fly correctly? I'm reminded of the Quantas QF32 flight, where pilots were nearly overwhelmed by the endless amount of errors and checklists they had to perform. [2] [1] https://www.youtube.com/watch?v=lIusD6Z-3cU https://www.youtube.com/watch?v=lIusD6Z-3cU [2] https://www.news.com.au/travel/travel-advice/flights/inside-the-cockpit-on-qf32-how-the-worlds-worst-aviation-disaster-was-averted/news-story/62f3b73db38751b6ae0b3769058a48da https://www.news.com.au/travel/travel-advice/flights/inside-...
    - dredmorbius 7y ago
      Very good points. And in the case of MCAS, physically unable to exert the effort to overcome the automated trim settings. (Posted above): https://youtube.com/watch?v=aoNOVlxJmow https://youtube.com/watch?v=aoNOVlxJmow
  - burfog 7y ago
    That first crash is a good example of multiple minor problems joining together to create a disaster. 1. "they didn't even get as far as switching off the stab trim" means they were incompetent. 2. MCAS, obviously, was a bad design 3. there was a physical issue with the sensor, possibly due to a bird strike Fix any one of those, and the flight wouldn't have crashed.
    - pbhjpbhj 7y ago
      >means they were incompetent // I thought a central part of this was that there was according to Boeing no need to train on this particular aircraft because it was so close operationally to the 737NG. But that in fact the correct response in the particular situation is vastly different. So yes, kinda "incompetence" but more "ignorant due to Boeing's assertions that training wasn't needed"; ie the blame should not primarily rest on the pilots.(?) I'm ignorant on the details, but this sort of article seems convincing: > It’s probably this counterintuitive characteristic, which goes against what has been trained many times in the simulator for unwanted autopilot trim or manual trim runaway, which has confused the pilots of JT610. They learned that holding against the trim stopped the nose down, and then they could take action, like counter-trimming or outright CUTOUT the trim servo. But it didn’t. After a 10 second trim to a 2.5° nose down stabilizer position, the trimming started again despite the Pilots pulling against it. The faulty high AOA signal was still present. > How should they know that pulling on the Yoke didn’t stop the trim? It was described nowhere; neither in the aircraft’s manual, the AFM, nor in the Pilot’s manual, the FCOM. This has created strong reactions from airlines with the 737 MAX on the flight line and their Pilots. They have learned the NG and the MAX flies the same. They fly them interchangeably during the week. > (https://leehamnews.com/2018/11/14/boeings-automatic-trim-for-the-737-max-was-not-disclosed-to-the-pilots/ https://leehamnews.com/2018/11/14/boeings-automatic-trim-for...) //
  - mjevans 7y ago
    I agree with the better automation line. If a human is pulling back on the thing that says "plane needs to go UP" believe what they're requesting.
    - erobbins 7y ago
      the AF flight that was lost over the Atlantic years back (10 years now maybe?) did just that, when the pilots believed that the plane's automation was in a state that would not allow them to do anything that would result in unrecoverable flight... so they stalled it all the way into the ocean. The problem here is nearly identical to the problems with self driving cars. The automation is capable of handling 95% of situations, but the 5% it's not capable of is not clear to either the operators or the software itself. I firmly believe that both car and air travel need to be either 100% completely automated, or 100% under the control of the operators with well defined areas where the automation systems will ASSIST but always yield to the well trained (pilots) or poorly trained (car drivers) when requested. A human operator is able to think outside the box, and is not limited to what code has been conceived and written.
      - mjevans 7y ago
        That sounds more like an issue of not correctly communicating the detected problem to the humans. In any event, the situation where the humans aren't processing the data correctly and doing illogical things as a result would always lead to failure outcomes, until the point where we no longer allow humans to be pilots/operators at all.
        nikanj 7y ago
        The cockpit recording had a very loud stall alarm going in the background. The human brain is absolutely amazing in it's ability to tune out signals
Zancarius 7y ago
Depends on the aircraft. Some modern jetliners are using fly-by-wire, while others have hydraulically-boosted controls. Some still rely on cable-and-pulley. Either way, as I understand, it wouldn't matter with the MCAS-related MAX aircraft crashes. The elevator trim is able to move the entire elevator (literally, the entire elevator moves in response to the jackscrew controlled by the trim system) to such an extent that, depending on CG, airspeed, and other factors, it cannot be overpowered by moving the control surface to its full deflection. So whether or not the MAX had boosted controls or fly-by-wire probably wouldn't have mattered in the case the aircraft were trimmed fully nose-down. The pilots would have been struggling to maintain control either way. That's why there's stabilizer trim cut-out switches and manual trim. I'd highly recommend Mentour Pilot's videos on the subject, links below: Runaway Stabilizer: How to stop MCAS - https://www.youtube.com/watch?v=xixM_cwSLcQ https://www.youtube.com/watch?v=xixM_cwSLcQ Boeing 737 Unable to Trim! Cockpit video (full flight sim) - https://www.youtube.com/watch?v=aoNOVlxJmow https://www.youtube.com/watch?v=aoNOVlxJmow Five questions about the Boeing 737 MAX Answered - https://www.youtube.com/watch?v=CD0JabYjF3A https://www.youtube.com/watch?v=CD0JabYjF3A
- lisper 7y ago
  > Boeing 737 Unable to Trim! Cockpit video (full flight sim) - https://www.youtube.com/watch?v=aoNOVlxJmow https://www.youtube.com/watch?v=aoNOVlxJmow Start at 13:20 to skip straight to the relevant bit.
  - Zancarius 7y ago
    Thank you so much, lisper! I didn't have a chance to re-watch to post timestamps. Much appreciated!
    - lisper 7y ago
      You bet.
computerex 7y ago
Boeing went complete retard with this. Which is funny, because historically Boeing is the company known to give final authority of the plane to the pilot, in contrast to their rival Airbus which relies more on the onboard fly-by-wire system. Modern planes have hydraulics and fly-by-wire, so pilots don't get the feedback they'd get if their controls were directly connected to the airfoils. To give pilots this feedback, Boeing simulates it mechanically by exerting force on the yoke. Normally this is fine and dandy, until the critical AoA sensor malfunctions and makes the computer think the plane is in a different attitude than it actually is in.
- foldr 7y ago
  MCAS has nothing to do with force feedback on the yoke. MCAS adjusts the trim. The 737 does not have artificial feel in any case, as far as I know. There's a direct mechanical linkage from the yoke to the control surfaces, so no artificial feel is necessary.
  - computerex 7y ago
    > MCAS has nothing to do with force feedback on the yoke When did I say it has anything to do with it? > The 737 does not have artificial feel in any case, as far as I know. There's a direct mechanical linkage from the yoke to the control surfaces, so no artificial feel is necessary. Modern planes come with stick shaker-pusher systems: https://www.flyingmag.com/how-it-works-stick-shaker-pusher https://www.flyingmag.com/how-it-works-stick-shaker-pusher That's what I was referring to. Also whilst the 737 does have mechanical linkages to the control surfaces, they are there primarily for redundancy so the plane is flyable in case of hydraulics/power failure. By definition any hydraulics assisted system requires artificial force feedback.
    - foldr 7y ago
      > Modern planes come with stick shaker-pusher systems. That's what I was referring to. Hmm? You were talking about systems that mimic the yoke feel of an aircraft with manual controls. A stick shaker is an emergency warning system that would never once activate on a normal flight. It has no effect on the feel of the controls. >When did I say it has anything to do with it? In the comment I replied to: "To give pilots this feedback, Boeing simulates it mechanically by exerting force on the yoke. Normally this is fine and dandy, until the critical AoA sensor malfunctions and makes the computer think the plane is in a different attitude than it actually is in."

tomglynch 7y ago

> putting pilots into a situation where they can't command the airplane even if they want to is a bit extreme. I agree, this is the main issue. In both cases if pilots had a clear option to just switch off MCAS we would have not lost over 500 lives.

gok 7y ago
Unlikely. In the case of the first crash, they didn't even get as far as switching off the stab trim (they were flipping through the flight manual to find it as the plane crashed). A second switch would have done nothing if they couldn't remember how to use the first one. Yet another switch in a cockpit (which already has hundreds of them) would also have been yet another way to create an emergency by having a switch accidentally flipped the wrong way. In an emergency it has repeatedly been shown that pilots often forget complicated/rare recovery procedures. We need to stop relying on humans to perform at a superhuman level in these situations; better automation is the only way out.
- infecto 7y ago
  Better automation like MCAS?
- zubspace 7y ago
  On the other hand, there are many who believe, that automation got us into this. The more we automate, the more we depend on it which leads to problems if exceptional situations occur. [1] Maybe the 737 Max is just too complex and relies too much on automation to fly correctly? I'm reminded of the Quantas QF32 flight, where pilots were nearly overwhelmed by the endless amount of errors and checklists they had to perform. [2] [1] https://www.youtube.com/watch?v=lIusD6Z-3cU https://www.youtube.com/watch?v=lIusD6Z-3cU [2] https://www.news.com.au/travel/travel-advice/flights/inside-the-cockpit-on-qf32-how-the-worlds-worst-aviation-disaster-was-averted/news-story/62f3b73db38751b6ae0b3769058a48da https://www.news.com.au/travel/travel-advice/flights/inside-...
  - dredmorbius 7y ago
    Very good points. And in the case of MCAS, physically unable to exert the effort to overcome the automated trim settings. (Posted above): https://youtube.com/watch?v=aoNOVlxJmow https://youtube.com/watch?v=aoNOVlxJmow
- burfog 7y ago
  That first crash is a good example of multiple minor problems joining together to create a disaster. 1. "they didn't even get as far as switching off the stab trim" means they were incompetent. 2. MCAS, obviously, was a bad design 3. there was a physical issue with the sensor, possibly due to a bird strike Fix any one of those, and the flight wouldn't have crashed.
  - pbhjpbhj 7y ago
    >means they were incompetent // I thought a central part of this was that there was according to Boeing no need to train on this particular aircraft because it was so close operationally to the 737NG. But that in fact the correct response in the particular situation is vastly different. So yes, kinda "incompetence" but more "ignorant due to Boeing's assertions that training wasn't needed"; ie the blame should not primarily rest on the pilots.(?) I'm ignorant on the details, but this sort of article seems convincing: > It’s probably this counterintuitive characteristic, which goes against what has been trained many times in the simulator for unwanted autopilot trim or manual trim runaway, which has confused the pilots of JT610. They learned that holding against the trim stopped the nose down, and then they could take action, like counter-trimming or outright CUTOUT the trim servo. But it didn’t. After a 10 second trim to a 2.5° nose down stabilizer position, the trimming started again despite the Pilots pulling against it. The faulty high AOA signal was still present. > How should they know that pulling on the Yoke didn’t stop the trim? It was described nowhere; neither in the aircraft’s manual, the AFM, nor in the Pilot’s manual, the FCOM. This has created strong reactions from airlines with the 737 MAX on the flight line and their Pilots. They have learned the NG and the MAX flies the same. They fly them interchangeably during the week. > (https://leehamnews.com/2018/11/14/boeings-automatic-trim-for-the-737-max-was-not-disclosed-to-the-pilots/ https://leehamnews.com/2018/11/14/boeings-automatic-trim-for...) //
- mjevans 7y ago
  I agree with the better automation line. If a human is pulling back on the thing that says "plane needs to go UP" believe what they're requesting.
  - erobbins 7y ago
    the AF flight that was lost over the Atlantic years back (10 years now maybe?) did just that, when the pilots believed that the plane's automation was in a state that would not allow them to do anything that would result in unrecoverable flight... so they stalled it all the way into the ocean. The problem here is nearly identical to the problems with self driving cars. The automation is capable of handling 95% of situations, but the 5% it's not capable of is not clear to either the operators or the software itself. I firmly believe that both car and air travel need to be either 100% completely automated, or 100% under the control of the operators with well defined areas where the automation systems will ASSIST but always yield to the well trained (pilots) or poorly trained (car drivers) when requested. A human operator is able to think outside the box, and is not limited to what code has been conceived and written.
    - mjevans 7y ago
      That sounds more like an issue of not correctly communicating the detected problem to the humans. In any event, the situation where the humans aren't processing the data correctly and doing illogical things as a result would always lead to failure outcomes, until the point where we no longer allow humans to be pilots/operators at all.
      - nikanj 7y ago
        The cockpit recording had a very loud stall alarm going in the background. The human brain is absolutely amazing in it's ability to tune out signals

Zancarius 7y ago

Depends on the aircraft. Some modern jetliners are using fly-by-wire, while others have hydraulically-boosted controls. Some still rely on cable-and-pulley. Either way, as I understand, it wouldn't matter with the MCAS-related MAX aircraft crashes. The elevator trim is able to move the entire elevator (literally, the entire elevator moves in response to the jackscrew controlled by the trim system) to such an extent that, depending on CG, airspeed, and other factors, it cannot be overpowered by moving the control surface to its full deflection. So whether or not the MAX had boosted controls or fly-by-wire probably wouldn't have mattered in the case the aircraft were trimmed fully nose-down. The pilots would have been struggling to maintain control either way. That's why there's stabilizer trim cut-out switches and manual trim. I'd highly recommend Mentour Pilot's videos on the subject, links below: Runaway Stabilizer: How to stop MCAS - https://www.youtube.com/watch?v=xixM_cwSLcQ https://www.youtube.com/watch?v=xixM_cwSLcQ Boeing 737 Unable to Trim! Cockpit video (full flight sim) - https://www.youtube.com/watch?v=aoNOVlxJmow https://www.youtube.com/watch?v=aoNOVlxJmow Five questions about the Boeing 737 MAX Answered - https://www.youtube.com/watch?v=CD0JabYjF3A https://www.youtube.com/watch?v=CD0JabYjF3A

lisper 7y ago
> Boeing 737 Unable to Trim! Cockpit video (full flight sim) - https://www.youtube.com/watch?v=aoNOVlxJmow https://www.youtube.com/watch?v=aoNOVlxJmow Start at 13:20 to skip straight to the relevant bit.
- Zancarius 7y ago
  Thank you so much, lisper! I didn't have a chance to re-watch to post timestamps. Much appreciated!
  - lisper 7y ago
    You bet.

computerex 7y ago

Boeing went complete retard with this. Which is funny, because historically Boeing is the company known to give final authority of the plane to the pilot, in contrast to their rival Airbus which relies more on the onboard fly-by-wire system. Modern planes have hydraulics and fly-by-wire, so pilots don't get the feedback they'd get if their controls were directly connected to the airfoils. To give pilots this feedback, Boeing simulates it mechanically by exerting force on the yoke. Normally this is fine and dandy, until the critical AoA sensor malfunctions and makes the computer think the plane is in a different attitude than it actually is in.

foldr 7y ago
MCAS has nothing to do with force feedback on the yoke. MCAS adjusts the trim. The 737 does not have artificial feel in any case, as far as I know. There's a direct mechanical linkage from the yoke to the control surfaces, so no artificial feel is necessary.
- computerex 7y ago
  > MCAS has nothing to do with force feedback on the yoke When did I say it has anything to do with it? > The 737 does not have artificial feel in any case, as far as I know. There's a direct mechanical linkage from the yoke to the control surfaces, so no artificial feel is necessary. Modern planes come with stick shaker-pusher systems: https://www.flyingmag.com/how-it-works-stick-shaker-pusher https://www.flyingmag.com/how-it-works-stick-shaker-pusher That's what I was referring to. Also whilst the 737 does have mechanical linkages to the control surfaces, they are there primarily for redundancy so the plane is flyable in case of hydraulics/power failure. By definition any hydraulics assisted system requires artificial force feedback.
  - foldr 7y ago
    > Modern planes come with stick shaker-pusher systems. That's what I was referring to. Hmm? You were talking about systems that mimic the yoke feel of an aircraft with manual controls. A stick shaker is an emergency warning system that would never once activate on a normal flight. It has no effect on the feel of the controls. >When did I say it has anything to do with it? In the comment I replied to: "To give pilots this feedback, Boeing simulates it mechanically by exerting force on the yoke. Normally this is fine and dandy, until the critical AoA sensor malfunctions and makes the computer think the plane is in a different attitude than it actually is in."