2 ms·

A good rule would be to keep MCAS active, choosing to use the sensor that produces the less-extreme adjustment.

• darkpuma 8y ago
  Eh, that kind of makes a certain amount of sense, but I don't think that's quite right. Determining which of the two sensors is less-extreme supposes knowledge about the airframe's current state. If he aircraft is currently in a very high angle of attack low speed stall, then the sensor that says everything is A-Okay is the extreme sensor. I understand that's not what you mean, that the sensor indicating a situation closes to nominal flight should be chosen, but I think the sticky part is that MCAS isn't a system meant for normal flight conditions. MCAS is only supposed to be active when the aircraft is in an extreme scenario. So in fact if the sensor with "less-extreme adjustment" is preferred, in a way that actually means the system functions as I suggested: MCAS is disabled if the sensors disagree. But not quite. In your scheme if both the sensors are extreme but disagree, MCAS would be active to the lesser extent. But in my scheme, if both sensors are extreme but disagree, MCAS would be totally inactive (while leaving the pilot with electronic stabilizer trim control of course, allowing the pilot to manually do anything MCAS would be capable of doing.)