3 ms·

This and other sources disagrees with you: http://www.b737.org.uk/mcas.htm http://www.b737.org.uk/mcas.htm >This abnormal nose-up pitching is not allowable und

by dTal 6y ago

This and other sources disagrees with you: http://www.b737.org.uk/mcas.htm http://www.b737.org.uk/mcas.htm >This abnormal nose-up pitching is not allowable under 14CFR §25.203(a) "Stall characteristics". Several aerodynamic solutions were introduced such as revising the leading edge stall strip and modifying the leading edge vortilons but they were insufficient to pass regulation. MCAS was therefore introduced to give an automatic nose down stabilizer input during elevated AoA when flaps are up. The 737 Max was not certifiable without MCAS at all.

throwaway0a5e 6y ago
The law states: >it must be possible to produce and to correct roll and yaw by unreversed use of the aileron and rudder controls, up to the time the airplane is stalled. No abnormal nose-up pitching may occur. The longitudinal control force must be positive up to and throughout the stall. In addition, it must be possible to promptly prevent stalling and to recover from a stall by normal use of the controls. Pretty much all commercial airliners are gonna pitch up if you're nose high and have the throttle pinned. Arguably the degree to which the MAX does this is novel. I think it likely handles like shit in that part of the flight envelope but does it really handle like such shit that it's not safe? I don't think so. Remember, this is basically a company truck. You just have to know it's an issue and be trained to operate it properly. Most people would be appalled at the braking characteristics of unladen semi-trucks but it's a non-issue because everyone who has to drive one knows that in those specific circumstances it will handle like crap. At the end of the day it is a matter of degree and opinion. Yes, you can win some quick virtue points by taking a stand in the name of safety and saying that nothing more than the most minor pitch up is acceptable but I think that had this aircraft gone for a FAA certification as a new type it would have passed just fine.
- Swenrekcah 6y ago
  Not the one you responded to but: I don't know enough about airplanes to say if the MAX could have certified as it's own type. I'd like to hope it could because if not then that would show a very sorry state of affairs indeed. But the big issue with the MAX is not that it handles differently, it is that Boeing lied to everyone about that fact. Then they made another semi-unforgivable error by masking the handling with software, ok, but didn't even take the most basic steps available to ensure some redundancy in that software. It is just so very very bad engineering and mindset that it's hard to describe. Would I fly on a MAX if and when they get clearance again? Maybe after it's been flying for a year or so, and depending on what some trusted people and institutions say about it.
  - throwaway0a5e 6y ago
    >But the big issue with the MAX is not that it handles differently, it is that Boeing lied to everyone about that fact. Then they made another semi-unforgivable error by masking the handling with software, ok, but didn't even take the most basic steps available to ensure some redundancy in that software. Which is exactly what I'm saying and the opposite of what the author and DTAL are saying. >It is just so very very bad engineering and mindset that it's hard to describe. I don't think it's even a mindset. It's that sort of "nobody is responsible for a large enough part of the system to be able to stop things and force things to be done right" situation that a lot of big-cos get into that results in them crapping out half baked products. >Would I fly on a MAX if and when they get clearance again? Maybe after it's been flying for a year or so, and depending on what some trusted people and institutions say about it. For me the decision would hinge on what training the pilots get.
    - Swenrekcah 6y ago
      >I don't think it's even a mindset. It's that sort of "nobody is responsible for a large enough part of the system to be able to stop things and force things to be done right" situation that a lot of big-cos get into that results in them crapping out half baked products. I agree that plays a part. But the people in charge of the flight computer software should know better than to have no redundancy. And the executives definately are able to stop things and force them to be done right, and instill in their employees a mentality of safety-first. But their bonuses might have suffered, so...

by dTal 6y ago

throwaway0a5e 6y ago

The law states: >it must be possible to produce and to correct roll and yaw by unreversed use of the aileron and rudder controls, up to the time the airplane is stalled. No abnormal nose-up pitching may occur. The longitudinal control force must be positive up to and throughout the stall. In addition, it must be possible to promptly prevent stalling and to recover from a stall by normal use of the controls. Pretty much all commercial airliners are gonna pitch up if you're nose high and have the throttle pinned. Arguably the degree to which the MAX does this is novel. I think it likely handles like shit in that part of the flight envelope but does it really handle like such shit that it's not safe? I don't think so. Remember, this is basically a company truck. You just have to know it's an issue and be trained to operate it properly. Most people would be appalled at the braking characteristics of unladen semi-trucks but it's a non-issue because everyone who has to drive one knows that in those specific circumstances it will handle like crap. At the end of the day it is a matter of degree and opinion. Yes, you can win some quick virtue points by taking a stand in the name of safety and saying that nothing more than the most minor pitch up is acceptable but I think that had this aircraft gone for a FAA certification as a new type it would have passed just fine.

Swenrekcah 6y ago
Not the one you responded to but: I don't know enough about airplanes to say if the MAX could have certified as it's own type. I'd like to hope it could because if not then that would show a very sorry state of affairs indeed. But the big issue with the MAX is not that it handles differently, it is that Boeing lied to everyone about that fact. Then they made another semi-unforgivable error by masking the handling with software, ok, but didn't even take the most basic steps available to ensure some redundancy in that software. It is just so very very bad engineering and mindset that it's hard to describe. Would I fly on a MAX if and when they get clearance again? Maybe after it's been flying for a year or so, and depending on what some trusted people and institutions say about it.
- throwaway0a5e 6y ago
  >But the big issue with the MAX is not that it handles differently, it is that Boeing lied to everyone about that fact. Then they made another semi-unforgivable error by masking the handling with software, ok, but didn't even take the most basic steps available to ensure some redundancy in that software. Which is exactly what I'm saying and the opposite of what the author and DTAL are saying. >It is just so very very bad engineering and mindset that it's hard to describe. I don't think it's even a mindset. It's that sort of "nobody is responsible for a large enough part of the system to be able to stop things and force things to be done right" situation that a lot of big-cos get into that results in them crapping out half baked products. >Would I fly on a MAX if and when they get clearance again? Maybe after it's been flying for a year or so, and depending on what some trusted people and institutions say about it. For me the decision would hinge on what training the pilots get.
  - Swenrekcah 6y ago
    >I don't think it's even a mindset. It's that sort of "nobody is responsible for a large enough part of the system to be able to stop things and force things to be done right" situation that a lot of big-cos get into that results in them crapping out half baked products. I agree that plays a part. But the people in charge of the flight computer software should know better than to have no redundancy. And the executives definately are able to stop things and force them to be done right, and instill in their employees a mentality of safety-first. But their bonuses might have suffered, so...