Indonesian aircraft missing off Jakarta

[CONSO]

..... ZZUF
For this MCAS system to work the aircraft needs to "know" when it has reached the particular flight envelope corner. I would expect that inputs such as alpha, alpha rate, bank angle, flap setting, power setting, G, IAS/CAS, possibly CG and others.
So, how did the aircraft think it was in the corner point, just waiting for an alpha signal within the trigger range? Surely not a single failure?
Anyway this is just fantasy.[/QUOTE]


FAA and BA DOES think a single AOA failure can cause MCAS ' failure'

DATE: November 7, 2018
AD #: 2018-23-51
Emergency Airworthiness Directive (AD) 2018-23-51 is sent to owners and operators of The
Boeing Company Model 737-8 and -9 airplanes.
Background
This emergency AD was prompted by analysis performed by the manufacturer showing that if
an erroneously high single angle of attack (AOA) sensor input is received by the flight control
system, there is a potential for repeated nose-down trim commands of the horizontal stabilizer. This
condition, if not addressed, could cause the flight crew to have difficulty controlling the airplane, and
lead to excessive nose-down attitude, significant altitude loss, and possible impact with terrain.