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Old 11th Mar 2019, 08:29
  #263 (permalink)  
Join Date: Oct 2017
Location: Vienna
Posts: 104
Originally Posted by BRE View Post
MCAS sounds a lot like Airbus Normal Law, specifically pitch control and alpha protection. How does the Boeing implementation differ?
Uh, they have nothing in common. Normal Law will ensure whatever you do with the stick, the airplane will remain inside the flight envelope. MCAS just trims the nose forward every 5s regardless of any other parameters.

Perhaps the bigger issue is the core design. Airbus, being FBW by design, has triple sensors. If one fails, the other 2 overrule the broken one. Boeing relies on 2 sensors, if one breaks all hell will broke loose.

Also, on a Bus, if things go south, the HAL will say "sorry, your plane", turn into degraded/direct law and let the pilot handle it (which does not always work, e.g. AF447). Mcas will fight the pilots and try to get its way unless it's manually shut down.

In short, mcas is probably going to be known as one of the biggest f***ups in modern aviation history (yeah, I'm jumping to conclusions fas here, but time will tell).
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