“In a situation where there is erroneous AOA information, it will not lead to activation of MCAS,” says Sinnett. He underlines that the entire speed-trim system, including the MCAS, will be inhibited for the remainder of the flight if data from the two vanes varies by more than 5.5 deg. If an AOA disagreement of more than 10 deg. occurs between the sensors for more than 10 sec., it will be flagged to the crew on the primary flight display.
Is there a reason for the different thresholds for AoA disagree and STS/MCAS inhibit?
So if an AoA vane sticks so that it's (say) 8 degrees offset from the other for a period, STS and MCAS will be disabled for the remainder of the flight, with a change to handling characteristics but no crew warning - or is there an STS/MCAS warning indication as well as AoA disagree?