Originally Posted by
Hi_Tech
I have this sent by someone. Not sure 100% if it is authentic. Looks authentic to me as MCAS is mentioned. The two switches (Left lower corner) (STAB and B/U not mentioned here) are in series for cutting out the Stab Trim Control power. So either switch will cut the control power to the Motor. One switch (A) cuts out the Autopilot enable signal and other (B) cuts the signal from FCC disabling the manual electric, STS and MCAS. That is my inference. You can come to your own conclusion if you can read the circuit d iagram.
Hope this helps.
Thanks for the diagram. The two cutout switches are in series so they are the STAB and B/U.
The cut out funktion works over the R64 main relay. At the same time the FCC knows that it is cut out. What worries me more is, that the MCAS signal seem to be able to switch the Stab motor into fast mode as when the flaps where down via K5. My assumption is, that since the increase to 2.5 degrees MCAS stab was necessary, MCAS can move the stab faster than the pilots can in a flap up condition.