PPRuNe Forums - View Single Post - MCAS ALTITUDE V ATTITUDE ??
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Old 15th Mar 2019, 21:10
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FCeng84
 
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Originally Posted by Vessbot
There is no "but." The sections before and after say two unrelated things that are not in contradiction. ALTitude is one of the inputs that determines at what AOA the MCAS will make a stab input. ATTitude is what the runaway stab procedure wants you to control with the column and manual trim.
Good idea to pull aside and have a level setting. I concur with everything added to the thread so far. Let me point to one possible source for the confusion about the role of ALTitude in the activation of MCAS. I recall that in the ET accident thread at one point there were several submissions wondering if MCAS could have played a role based on the data suggesting that the airplane did not gain much ALTitude and thus speculating that the flaps would have still been extended. I believe that at least one entry suggested that on climbing out of Addis Ababa it would not be abnormal to be cleaned up to flaps up by the point where the airplane was 1000' above the runway ALTitude. This may have been seen by some as indication that MCAS has logic to prevent activation below 1000'. I am not aware of any direct use of ALTitude in the activation of MCAS. I am checking with a source and will report back once this is confirmed or denied.
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