3 ms·

Doubtful. Older models don't have the oversized, forward-mounted engines, and thus don't have as much of an AoA problem as the MAX does in typical flight condit

Doubtful. Older models don't have the oversized, forward-mounted engines, and thus don't have as much of an AoA problem as the MAX does in typical flight conditions. That's the reason the MAX should have been a separate classification with specific hands-on training.

dsfyu404ed 8y ago
The MAX is stable in normal flight. It's only when you are pitched up does the engine placement make it want to pitch up even more (and it is only a problem at a speed that is low enough that the normal stabilizer control doesn't have enough control authority to push it back) hence MCAS forcing the nose down every so often via the trim. A normal flight does include pitching up but it does not include pitching up at such a low speed that a little more pitch would quickly cause a stall. MCAS (or at least the nose down function) is specifically designed for an edge case (in that it should be sitting there watching, not actually doing anything during a normal flight). edited
- Rooster61 8y ago
  Hence why I said "typical flight conditions", which includes pitching up. Point being, its utterly commonplace for a plane to pitch up at some point during the flight. They weren't doing anything out of the ordinary.
- Rooster61 8y ago
  > MCAS is specifically designed for an edge case Source? That's the first I've heard that it's only for edge cases.
  - dsfyu404ed 8y ago
    If the pilot, who hopefully has thicker skin than people on the internet, moves the buttons and levers properly MCAS should never have to do anything. It's only supposed to actually do anything when you let the nose pitch up a little too much (which the system will detect using the AoA sensors)[0]. It's like automatic braking in a new car, if you drive the way you're "expected to" you shouldn't be activating it often. [0] https://theaircurrent.com/aviation-safety/what-is-the-boeing-737-max-maneuvering-characteristics-augmentation-system-mcas-jt610/ https://theaircurrent.com/aviation-safety/what-is-the-boeing...
    - Rooster61 8y ago
      Again, please post a source backing this claim up. And it would be appreciated if the folks that died commanding this flight were not referred to as "meat bags".
      - dsfyu404ed 8y ago
        Edited the original.
    - Gibbon1 8y ago
      > when you let the nose pitch up a little too much Or flying into windshear changes the angle of attack on you.
  - pdonis 8y ago
    > That's the first I've heard that it's only for edge cases. It's only supposed to activate in a specific edge case (high angle of attack, manual flight, no flaps, low airspeed). That's been discussed plenty online (including previous threads here at HN). But that assumes that the angle of attack sensors are accurate. If the AoA sensors are inaccurate, as they were on this flight (more specifically the left one), MCAS can activate when it's not supposed to. That's what happened here.
    - cjbprime 8y ago
      I don't agree with "low airspeed". You can exceed critical AoA (and therefore stall) at any airspeed.
      - pdonis 8y ago
        > You can exceed critical AoA (and therefore stall) at any airspeed. I wasn't talking about at what airspeeds a stall is possible. I was talking about at what airspeeds MCAS is designed to activate (assuming correct AoA sensor input).
- pdonis 8y ago
  > MCAS (or at least the nose down function) is specifically designed for an edge case Yes, and it will only activate during that edge case if the AoA inputs are accurate. But they weren't. And so MCAS activated when it shouldn't have, and did things that the pilots could not recover from because they were things MCAS should never have done in the first place. That's the problem.

dsfyu404ed 8y ago

The MAX is stable in normal flight. It's only when you are pitched up does the engine placement make it want to pitch up even more (and it is only a problem at a speed that is low enough that the normal stabilizer control doesn't have enough control authority to push it back) hence MCAS forcing the nose down every so often via the trim. A normal flight does include pitching up but it does not include pitching up at such a low speed that a little more pitch would quickly cause a stall. MCAS (or at least the nose down function) is specifically designed for an edge case (in that it should be sitting there watching, not actually doing anything during a normal flight). edited

Rooster61 8y ago
Hence why I said "typical flight conditions", which includes pitching up. Point being, its utterly commonplace for a plane to pitch up at some point during the flight. They weren't doing anything out of the ordinary.
Rooster61 8y ago
> MCAS is specifically designed for an edge case Source? That's the first I've heard that it's only for edge cases.
- dsfyu404ed 8y ago
  If the pilot, who hopefully has thicker skin than people on the internet, moves the buttons and levers properly MCAS should never have to do anything. It's only supposed to actually do anything when you let the nose pitch up a little too much (which the system will detect using the AoA sensors)[0]. It's like automatic braking in a new car, if you drive the way you're "expected to" you shouldn't be activating it often. [0] https://theaircurrent.com/aviation-safety/what-is-the-boeing-737-max-maneuvering-characteristics-augmentation-system-mcas-jt610/ https://theaircurrent.com/aviation-safety/what-is-the-boeing...
  - Rooster61 8y ago
    Again, please post a source backing this claim up. And it would be appreciated if the folks that died commanding this flight were not referred to as "meat bags".
    - dsfyu404ed 8y ago
      Edited the original.
  - Gibbon1 8y ago
    > when you let the nose pitch up a little too much Or flying into windshear changes the angle of attack on you.
- pdonis 8y ago
  > That's the first I've heard that it's only for edge cases. It's only supposed to activate in a specific edge case (high angle of attack, manual flight, no flaps, low airspeed). That's been discussed plenty online (including previous threads here at HN). But that assumes that the angle of attack sensors are accurate. If the AoA sensors are inaccurate, as they were on this flight (more specifically the left one), MCAS can activate when it's not supposed to. That's what happened here.
  - cjbprime 8y ago
    I don't agree with "low airspeed". You can exceed critical AoA (and therefore stall) at any airspeed.
    - pdonis 8y ago
      > You can exceed critical AoA (and therefore stall) at any airspeed. I wasn't talking about at what airspeeds a stall is possible. I was talking about at what airspeeds MCAS is designed to activate (assuming correct AoA sensor input).
pdonis 8y ago
> MCAS (or at least the nose down function) is specifically designed for an edge case Yes, and it will only activate during that edge case if the AoA inputs are accurate. But they weren't. And so MCAS activated when it shouldn't have, and did things that the pilots could not recover from because they were things MCAS should never have done in the first place. That's the problem.