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> The automated stall-prevention system on Boeing 737 MAX 8 and MAX 9 models ... can push it down unexpectedly and so strongly that flight crews can’t pull it

> The automated stall-prevention system on Boeing 737 MAX 8 and MAX 9 models ... can push it down unexpectedly and so strongly that flight crews can’t pull it back up. I'm surprised that Boeing designed a system that could override the strength of the pilot. I don't know how strong the normal autopilot controls are on a B-737-800 but on lighter aircraft it's a normal part of the preflight to make sure that you can overpower the autopilot with muscle if it fails.

cmurf 8y ago
These are all fly by wire airplanes, muscle has exactly zero to do with simply ignoring the input. You have to know what system is confused, and possibly why, in order to know what component or system needs to be reset or disabled. And these are the kinds of scenarios that continue to make me think autonomous cars in a hybrid environment (i.e. with human drivers) is just absurd. Flying planes is a standardized environment, and we can't even automate it end to end with available technology in idealized conditions, let alone in emergencies. And car driving is way more complicated (and I say that as a pilot). Having one inch precision for every bit of concrete, light bulb, paint on every airport in the world, is less data than what you'd see in one town, let alone a city, let alone all of them. The infrastructure standardization within a city is poor let alone across the country, and it evolves daily perhaps even by the hour.
- cjbprime 8y ago
  This doesn't sound right. Boeing planes are much less fly-by-wire than Airbus, and this is especially true for the older models such as the 757 in this crash.
  - sitharus 8y ago
    This crash involves a 737 MAX - a very modern fully fly-by-wire aeroplane. I think the 777 was the last Boeing jet with mechanical backup flight controls. The difference you're probably thinking of is the Boeing philosophy of ultimate pilot control vs the Airbus one of software restrictions. A pilot can fly a Boeing aircraft outside of its designed envelope, but an Airbus will restrict the inputs.
    - inferiorhuman 8y ago
      > This doesn't sound right. Boeing planes are much less fly-by-wire than Airbus, and this is especially true for the older models such as the 757 in this crash. The plane that crashed was not a 757 it was a 737 MAX. > This crash involves a 737 MAX - a very modern fully fly-by-wire aeroplane. The 737 MAX is NOT a fully FBW airplane. The MAX does have a FBW spoiler which the previous 737s (Jurassic, Classic, NG) lack. > The difference you're probably thinking of is the Boeing philosophy of ultimate pilot control vs the Airbus one of software restrictions. A pilot can fly a Boeing aircraft outside of its designed envelope, but an Airbus will restrict the inputs. That's not entirely true, all 737s will put additional pressure on the yoke when a stall is detected. You can fly a 737 into a stall, but with quite a bit of effort. Similarly you can fly a modern Airbus into a stall provided you're in one of the degraded "laws". Air France pilots did just that with an A330. Where the MAX differs from other 737s is that when a stall is detected it will trim the stabilizer -- even worse when the computer predicts a stall the 737 may end up trimming the stabilizer to the point that you cannot overcome it with the elevator. On a 737 the elevators respond quickly while the trim adjustments are much, much slower. If you're 5,000 ft in the air and Boeing decides to trim the stabilizer full down you may already crash by the time you can re-trim the plane and regain control. Previous 737s did NOT do this. I believe that LOT specifically emphasizes this in their MAX training, unsure if Lion Air did/does.
      - FabHK 8y ago
        inferiorhuman appears to know what he is talking about; you can safely ignore the comments preceding his (except the useful alternative link).
    - Serow225 8y ago
      737MAX is not fully FBW. Trim is one example...
- jhall1468 8y ago
  > Flying planes is a standardized environment, and we can't even automate it end to end with available technology in idealized conditions, let alone in emergencies. Well, it's not that we can't, it's that we haven't yet. Both Boeing and Airbus have treaded lightly into this territory. Hard to blame them, since most polling indicates a overwhelming majority of the public wouldn't get on an unmanned airplane. Furthermore, there's a few misconceptions here. Weather at 30,000 feet is nothing like weather on the surface of the earth. That said, the tech is pretty close to a reality, but when you have to drag the public along it slows the process down.
deleted 8y ago
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cmurf 8y ago

These are all fly by wire airplanes, muscle has exactly zero to do with simply ignoring the input. You have to know what system is confused, and possibly why, in order to know what component or system needs to be reset or disabled. And these are the kinds of scenarios that continue to make me think autonomous cars in a hybrid environment (i.e. with human drivers) is just absurd. Flying planes is a standardized environment, and we can't even automate it end to end with available technology in idealized conditions, let alone in emergencies. And car driving is way more complicated (and I say that as a pilot). Having one inch precision for every bit of concrete, light bulb, paint on every airport in the world, is less data than what you'd see in one town, let alone a city, let alone all of them. The infrastructure standardization within a city is poor let alone across the country, and it evolves daily perhaps even by the hour.

cjbprime 8y ago
This doesn't sound right. Boeing planes are much less fly-by-wire than Airbus, and this is especially true for the older models such as the 757 in this crash.
- sitharus 8y ago
  This crash involves a 737 MAX - a very modern fully fly-by-wire aeroplane. I think the 777 was the last Boeing jet with mechanical backup flight controls. The difference you're probably thinking of is the Boeing philosophy of ultimate pilot control vs the Airbus one of software restrictions. A pilot can fly a Boeing aircraft outside of its designed envelope, but an Airbus will restrict the inputs.
  - inferiorhuman 8y ago
    > This doesn't sound right. Boeing planes are much less fly-by-wire than Airbus, and this is especially true for the older models such as the 757 in this crash. The plane that crashed was not a 757 it was a 737 MAX. > This crash involves a 737 MAX - a very modern fully fly-by-wire aeroplane. The 737 MAX is NOT a fully FBW airplane. The MAX does have a FBW spoiler which the previous 737s (Jurassic, Classic, NG) lack. > The difference you're probably thinking of is the Boeing philosophy of ultimate pilot control vs the Airbus one of software restrictions. A pilot can fly a Boeing aircraft outside of its designed envelope, but an Airbus will restrict the inputs. That's not entirely true, all 737s will put additional pressure on the yoke when a stall is detected. You can fly a 737 into a stall, but with quite a bit of effort. Similarly you can fly a modern Airbus into a stall provided you're in one of the degraded "laws". Air France pilots did just that with an A330. Where the MAX differs from other 737s is that when a stall is detected it will trim the stabilizer -- even worse when the computer predicts a stall the 737 may end up trimming the stabilizer to the point that you cannot overcome it with the elevator. On a 737 the elevators respond quickly while the trim adjustments are much, much slower. If you're 5,000 ft in the air and Boeing decides to trim the stabilizer full down you may already crash by the time you can re-trim the plane and regain control. Previous 737s did NOT do this. I believe that LOT specifically emphasizes this in their MAX training, unsure if Lion Air did/does.
    - FabHK 8y ago
      inferiorhuman appears to know what he is talking about; you can safely ignore the comments preceding his (except the useful alternative link).
  - Serow225 8y ago
    737MAX is not fully FBW. Trim is one example...
jhall1468 8y ago
> Flying planes is a standardized environment, and we can't even automate it end to end with available technology in idealized conditions, let alone in emergencies. Well, it's not that we can't, it's that we haven't yet. Both Boeing and Airbus have treaded lightly into this territory. Hard to blame them, since most polling indicates a overwhelming majority of the public wouldn't get on an unmanned airplane. Furthermore, there's a few misconceptions here. Weather at 30,000 feet is nothing like weather on the surface of the earth. That said, the tech is pretty close to a reality, but when you have to drag the public along it slows the process down.

deleted 8y ago

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