feng said
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.
Granted I did a poor job in my comparison/confusion between altitude and attitude. And gums rightfully explained the difference - BUT that leaves myself and perhaps a few other much more qualified to guess just what sensors are involved in MCAS.
It ** seems** to me that the so called official descriptions and documents released so far leave MUCH to ' can you spot the problem within the next few minutes or die ' complex
MY confusion comes from the **apparent** assumption *** that IF the amount of stab trim is a function of speed and altitude- that both speed and altitude should/must have some sort of inout to when AOA triggers AND hows much movement per tweak results.
IF in general the trim movement is a function of speed - then at low speeds them trim/second would logically be larger . OK
Since speed is usually lower at low altitudes - re takeoff- in the simplified world-- then a logical question is how is altitude measured ? AGL or the standard baro altitude set at airport So what happens when airport alt is say 7000 above sea level - how is this compensated for re how much trim movement per second/ tweak?
While one can assume the whiz kids who programmed this kluge did take such issues into account- the Ethopian accident makes one wonder.- especially when one knows that mach number ( actual speed ) varies with actual temperature NOT altitude per standard tables. Which suggests that somehow a local ( to airplane ) temperature or at least at takeoff must somehow be fed into MCAS to prevent errors in stab movement.
Which then drives into the REAL effects of airspeed, altitude, temperature, airport altitude, inputs to MCAS and how derived/measured.
Seems to me one could legitimately question just how/where/when the above inputs are accommodated in a reliable fashion re MCAS activation. ? Dont expect to get answers here- but hopefully the code sausage making will be fully questioned.
Of course none of the above applies to the microsquish simulator crowd- and maybe not even the real simulator inputs ???
For the above - other than raise what I believe are real questions that need real answers by the experts on MCAS- I'll consider it my .0003 worth
