PPRuNe Forums - View Single Post - MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures
Old 16th Dec 2019, 06:31
  #4542 (permalink)  
MechEngr
 
Join Date: Oct 2019
Location: USA
Posts: 841
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Originally Posted by 568
"The AoA system that feeds it lies and also lies to the stall warning and stick shaker does not make sense".

With respect, how do you know the AoA lies?
Have you flown the 737?
Thanks.
We have two crashes because the AoA system lied. I don't need to fly a plane to know that.
It should have told the truth and signaled the equivalent of "The data is wrong" instead of reporting an erroneous 70 degree nose up AoA (ET302).

In both crashes the stall warning system, based on the AoA lie, caused aural and stick shaker warnings and disabled the autopilot, confusing the pilots about the status of the planes, which were not near stalling. The pilot's ability to detect MCAS actuation was adversely affected by the false warnings. Had that status been available to the MCAS systems engineers they are very likely to have added that state as a consideration in inhibiting the operation of the stabilizer trim motor, but they apparently believed AoA was reliable. It was an error to believe that, but the AoA subsystem developers would be the ones most familiar with the reliability of the AoA system.

So why didn't the aural stall warning group, the stick shaker group, or the autopilot group ever notice that the AoA could be unreliable and force the development of a clear indicator to the pilots about the reason for all three of them dumping on the pilots at the same time?
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