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Old 7th Dec 2018, 12:23
  #81 (permalink)  
safetypee
 
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More thoughts about system’s architecture and input sensors; primarily relating to MCAS, but perhaps some may relate to STS.

Although the aircraft airspeed system has ‘triplex’ integrity, this depends on the pilots selection of the best 2 out of 3 displays. However, I assume that the inputs into the trim computations are only dual (digital), and thus with a ‘speed disagreement’, in might be possible for an erroneous low value to activate trim.
Similarly an erroneous high thrust input, affecting MCAS.

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