New information confirms that MAX is similar to the NG, that the AoA analog interface is connected to two different computers, the Stall Management Yaw Damper (SMYD) and Air Data Inertial Reference Unit ADIRU) (which supplies the Flight Control Computer (FCC)). The SMYD uses AoA for Stall Warning and is evident by activation of Stick Shaker. FCC hosts MCAS, and if AoA from ADIRU too high it can trigger MCAS. The significance is that both SMYD and FCC responded to AoA large bias on JT043/JT610, and therefore, the AoA sensor must have been producing that erroneous output. The AoA sensor is what failed.
Boeing has confirmed that AoA disagree Alert will become basic, that AoA disagree will inhibit MCAS from triggering, and that MCAS cannot issue more than one trim command without AoA recovery.
The Senate grilled FAA acting Administrator Dan Elwell over excessive delegations and allowing Boeing to sell "safety critical items". Elwell stumbled on some key points, notably describing the 737 MAX as Fly-By-Wire and that the aft column cutout switch can stop MCAS trim commands.
Both Boeing and the FAA continue to insist that MCAS "runaway" is easy to detect and simple to respond to, but neither of these claims align with observations.