Comment Re: So, pilot error? (Score 1) 353
In fact, even with two sensors how does the system know which one is the malfunctioning sensor?
It doesn't, but that's nothing unusual. There are many systems on modern aircraft which involve dual sensors. When one malfunctions, the aircraft throws up a maintenance message basically saying "there's something wrong with this system".
Here's the problem, though: if you have 2 sensors, one of which is malfunctioning, and they're giving different readings within the normal operating range, which one do you rely on and why?
The 737 MAX 8 is equipped with 2 angle-of-attack sensors. Currently only 1 of the 2 is referenced during any given flight by the MCAS (which switches with weight-on-wheels). Even if you now obtain and compare readings from both during a flight, which one do you rely on to trigger the MCAS?
If you go by the one with the higher AoA reading, you're in the same situation that you were in previously (i.e. that the aircrew were in on the fatal flight).
If you go by the one with the lower AoA reading, you risk missing a potential stall due to an undetected high angle condition.
The suggestion of a 3-sensor voting comparison at least gives you a fighting chance to determine which sensor is giving the correct reading.