3 ms·

> MCAS did not exist because the 737 Max was unsafe, just different. You're saying the plane is "safe, just different" without MCAS? But Wikipedia says: "The

> MCAS did not exist because the 737 Max was unsafe, just different. You're saying the plane is "safe, just different" without MCAS? But Wikipedia says: "The MCAS flight control law was implemented on the 737 MAX to mitigate the aircraft's tendency to pitch up [...]" I'm a layman but it sure doesn't sound like safe or normal behavior for a passenger airplane to be fundamentally designed so that it "tends to pitch up"... is it? Are there other airliners that do such a thing?

l33tman 6y ago
The placements of the engines affected tendencies at some pretty extreme parts of the flight envelope as far as I understood, and MCAS helped make these tendencies similar to the previous 737. I guess an analogy could be that depending on the weight distribution and drive train in your car, it will have tendencies to oversteer or understeer when you go too fast into a turn in bad weather, or something. All cars have different behaviours and tendencies in these extreme circumstances. So the 737Max would not "pitch up" in most normal flying, this is under high AoA situations, like a tight overspeed banking turn I think.
deleted 6y ago
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roelschroeven 6y ago
All jet airliners have a tendency to pitch up under thrust, because of the low position of the engines. The 737 Max has a whole other issue separate from that, caused by the aerodynamic effects of the engines placed far forward of the wings. Airplanes are not allowed to pitch up more unless the pilot applies progressively more and more backward stick force. The 737 Max has a tendency in certain conditions (high angle of attack) to pitch up even when the pilot keeps applying a constant force. Some people argue that that behavior, without measures to prevent it, would disqualify the plane from certification completely. Others say that those measures are only needed to keep the Max under the same type rating as previous 737 generations. I'm inclined to the former, but I'm no expert so that's certainly not definitive.
choffa 6y ago
This tendency being different from previous versions. > The MCAS is intended to compensate in such cases [where the aircraft pitches up], modeling the pitching behavior of previous models, and meet a certain certification requirement, in order to enhance handling characteristics and thus minimizing the need for significant pilot retraining. With proper training/re-certification pilots would be trained in the _actual_ characteristics of the plane, thus being able to correct for this behaviour.
- design-material 6y ago
  Except Boeing also aggressively pitched that pilots didn't need to be extensively re-trained for the 737

l33tman 6y ago

The placements of the engines affected tendencies at some pretty extreme parts of the flight envelope as far as I understood, and MCAS helped make these tendencies similar to the previous 737. I guess an analogy could be that depending on the weight distribution and drive train in your car, it will have tendencies to oversteer or understeer when you go too fast into a turn in bad weather, or something. All cars have different behaviours and tendencies in these extreme circumstances. So the 737Max would not "pitch up" in most normal flying, this is under high AoA situations, like a tight overspeed banking turn I think.

deleted 6y ago

[deleted]

roelschroeven 6y ago

All jet airliners have a tendency to pitch up under thrust, because of the low position of the engines. The 737 Max has a whole other issue separate from that, caused by the aerodynamic effects of the engines placed far forward of the wings. Airplanes are not allowed to pitch up more unless the pilot applies progressively more and more backward stick force. The 737 Max has a tendency in certain conditions (high angle of attack) to pitch up even when the pilot keeps applying a constant force. Some people argue that that behavior, without measures to prevent it, would disqualify the plane from certification completely. Others say that those measures are only needed to keep the Max under the same type rating as previous 737 generations. I'm inclined to the former, but I'm no expert so that's certainly not definitive.

choffa 6y ago

This tendency being different from previous versions. > The MCAS is intended to compensate in such cases [where the aircraft pitches up], modeling the pitching behavior of previous models, and meet a certain certification requirement, in order to enhance handling characteristics and thus minimizing the need for significant pilot retraining. With proper training/re-certification pilots would be trained in the _actual_ characteristics of the plane, thus being able to correct for this behaviour.

design-material 6y ago
Except Boeing also aggressively pitched that pilots didn't need to be extensively re-trained for the 737