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It's not aerodynamically unstable. It's aerodynamically different than the 737-800 but Boeing decided instead of new pilot training and possibly re-certificatio

by kawfey 7y ago

It's not aerodynamically unstable. It's aerodynamically different than the 737-800 but Boeing decided instead of new pilot training and possibly re-certification, they would address the difference in it's flight characteristics by automatically adjusting the elevator trim when the aircraft is in a specific off-nominal situation such that the 737 MAX 8 feels and behaves just like the 737-800 (MCAS). That's not a bad engineering design decision IMO, but the follow-on decisions (or mistakes) made by Boeing (one AoA truth source instead of two, no extra training, zero indications, basically don't tell anyone about it) is the problem. Once those problems are fixed, no 737 MAX 8 will ever fail due to MCAS again. In fact it's going to be one of the - if not the - most scrutinized (and thereby safer) aircraft ever made.

hhas01 7y ago
I exaggerate slightly for [black] humor, but the point is hanging those huge engines so far forward puts its center of thrust uncomfortably ahead of its center of gravity, making it naturally want to pitch nose-up in flight. All the rest—dodgy sensors, crappy software kludge, no pilot retraining—is hacks laid on top of that initial flaw just to pretend it isn’t there. A lot of us here build complex systems for a living; if that isn’t a “smell”, what is? (Aerodynamically unstable design is a thing, btw, e.g. Typhoon. But that’s Military, which can afford fly-by-wire software that works.) A stable design might’ve lifted the airframe further from the ground to give those huge engines the clearance they need under the wing, keeping them to the COG and thus ensuring the plane continues to fly naturally level as per its original design. (Any air geeks want to check me on that?) But obviously that would’ve cost more, and now Boeing’s run by short-term profit chasers, not adult engineers, the attitude is “What can we get away with?”, not “What do we need to build?” That alone’s reason not to trust their bloody product any more. Not least cos what else might they be tempted to cut corners on? I mean, a shitty iPhone will screw up your day; a shitty Boeing will screw up the rest of your life. This is why Corporate Manslaughter laws should include hanging the Board by its heels.

by kawfey 7y ago

hhas01 7y ago

I exaggerate slightly for [black] humor, but the point is hanging those huge engines so far forward puts its center of thrust uncomfortably ahead of its center of gravity, making it naturally want to pitch nose-up in flight. All the rest—dodgy sensors, crappy software kludge, no pilot retraining—is hacks laid on top of that initial flaw just to pretend it isn’t there. A lot of us here build complex systems for a living; if that isn’t a “smell”, what is? (Aerodynamically unstable design is a thing, btw, e.g. Typhoon. But that’s Military, which can afford fly-by-wire software that works.) A stable design might’ve lifted the airframe further from the ground to give those huge engines the clearance they need under the wing, keeping them to the COG and thus ensuring the plane continues to fly naturally level as per its original design. (Any air geeks want to check me on that?) But obviously that would’ve cost more, and now Boeing’s run by short-term profit chasers, not adult engineers, the attitude is “What can we get away with?”, not “What do we need to build?” That alone’s reason not to trust their bloody product any more. Not least cos what else might they be tempted to cut corners on? I mean, a shitty iPhone will screw up your day; a shitty Boeing will screw up the rest of your life. This is why Corporate Manslaughter laws should include hanging the Board by its heels.