5 ms·

In all seriousness, i believe the reason why many think the crashes would not have happened in the US is because Southwest and others all ordered the planes wit

In all seriousness, i believe the reason why many think the crashes would not have happened in the US is because Southwest and others all ordered the planes with redundant sensors (in the area where it pertains to these crashes) whereas many overseas airlines did not.

simion314 7y ago
But did the checklist had the correct instructions on what to do in the case the extra alarm light would turn on? I think since MCAS was not disclosed there must not have been mentioned in the checklists either
- privateSFacct 7y ago
  The checklist for runaway stab trim is the same with MCAS -> but more likely and so a much more critical issue. Boeing should have updated pilots for sure - BUT many MCAS events may have occurred and been saved by the existing checklist which overlaps the issue.
temac 7y ago
It was my understanding that such redundancy for automation purposes did not even exist, and that despite having 2 AoA sensors only one was selected before a flight, with the computer switching the one to be used between each flight. Also Southwest certainly did not have all of the indicators at first, because they added some: https://theaircurrent.com/aviation-safety/southwest-airlines-is-adding-new-angle-of-attack-indicators-to-its-737-max-fleet/ https://theaircurrent.com/aviation-safety/southwest-airlines... (note that pretty much nobody used that kind of indicator before, so I don't say that to put blame on Southwest) It was also my understanding that some alarms including the AoA disagree were optional and for a fee even though probably activated by only needing to switch a bit somewhere in the software. So if Southwest had AoA disagree from the beginning (I don't know), well that's cool, but my interpretation is more like: that's not cool that some other airlines did not have it because of the dubious commercial practices of Boeing.
- privateSFacct 7y ago
  Correct - limited / no redundancy tech side. The design redundancy was the pilot in the loop - ie, in a stab trim situation pilot would follow a memory item. So this meant much less automation protection compared to systems without pilot in loop.

simion314 7y ago

But did the checklist had the correct instructions on what to do in the case the extra alarm light would turn on? I think since MCAS was not disclosed there must not have been mentioned in the checklists either

privateSFacct 7y ago
The checklist for runaway stab trim is the same with MCAS -> but more likely and so a much more critical issue. Boeing should have updated pilots for sure - BUT many MCAS events may have occurred and been saved by the existing checklist which overlaps the issue.

temac 7y ago

It was my understanding that such redundancy for automation purposes did not even exist, and that despite having 2 AoA sensors only one was selected before a flight, with the computer switching the one to be used between each flight. Also Southwest certainly did not have all of the indicators at first, because they added some: https://theaircurrent.com/aviation-safety/southwest-airlines-is-adding-new-angle-of-attack-indicators-to-its-737-max-fleet/ https://theaircurrent.com/aviation-safety/southwest-airlines... (note that pretty much nobody used that kind of indicator before, so I don't say that to put blame on Southwest) It was also my understanding that some alarms including the AoA disagree were optional and for a fee even though probably activated by only needing to switch a bit somewhere in the software. So if Southwest had AoA disagree from the beginning (I don't know), well that's cool, but my interpretation is more like: that's not cool that some other airlines did not have it because of the dubious commercial practices of Boeing.

privateSFacct 7y ago
Correct - limited / no redundancy tech side. The design redundancy was the pilot in the loop - ie, in a stab trim situation pilot would follow a memory item. So this meant much less automation protection compared to systems without pilot in loop.