3 ms·

[0] explains that fuel efficiency considerations prompted Boeing to push the altered 737's larger new engines well forward compared to prior iterations, causing

[0] explains that fuel efficiency considerations prompted Boeing to push the altered 737's larger new engines well forward compared to prior iterations, causing the airplane to pitch nose up in some maneuvers in unstable fashion. The MCAS system was introduced to compensate, and is the component that failed in both crashes. [0] https://hackaday.com/2019/03/14/mcas-and-the-737-when-small-changes-have-huge-consequences/ https://hackaday.com/2019/03/14/mcas-and-the-737-when-small-...

sbradford26 8y ago
Basically all planes have flight profiles where they are stable and unstable. Just because a plane is unstable in certain conditions, does not make it an unstable plane. A stable plane is a plane that is aerodynamically stable for most of its flight profile. The 737 MAX is just not stable in every condition that the old 737 NG was. And it probably goes the other way, there are most likely flight conditions where the 737 MAX is stable but the 737 NG is not. The difference is that pilots had been trained and have flown the old one for many years and trained to avoid the unstable conditions for the old 737. *Flight conditions meaning: air speed, AOA, bank angle, total thrust, altitude.
- VBprogrammer 8y ago
  > The difference is that pilots had been trained and have flown the old one for many years and trained to avoid the unstable conditions for the old 737. I don't think that's the case. MCAS was added to satisfy a requirement in the airworthiness certifications that requires positive control forces to increase AoA. The lift generated by the engine nacelles caused this to not be the case at high AoA. None of what has been revealed so far indicates that the pilots had issues related to the symptom, rather they had issues with MCAS. In a way the cure has been worse than the disease.

3 ms·

[0] explains that fuel efficiency considerations prompted Boeing to push the altered 737's larger new engines well forward compared to prior iterations, causing

by nwatson 8y ago

sbradford26 8y ago
Basically all planes have flight profiles where they are stable and unstable. Just because a plane is unstable in certain conditions, does not make it an unstable plane. A stable plane is a plane that is aerodynamically stable for most of its flight profile. The 737 MAX is just not stable in every condition that the old 737 NG was. And it probably goes the other way, there are most likely flight conditions where the 737 MAX is stable but the 737 NG is not. The difference is that pilots had been trained and have flown the old one for many years and trained to avoid the unstable conditions for the old 737. *Flight conditions meaning: air speed, AOA, bank angle, total thrust, altitude.
- VBprogrammer 8y ago
  > The difference is that pilots had been trained and have flown the old one for many years and trained to avoid the unstable conditions for the old 737. I don't think that's the case. MCAS was added to satisfy a requirement in the airworthiness certifications that requires positive control forces to increase AoA. The lift generated by the engine nacelles caused this to not be the case at high AoA. None of what has been revealed so far indicates that the pilots had issues related to the symptom, rather they had issues with MCAS. In a way the cure has been worse than the disease.