Originally Posted by
Mr Optimistic
Thanks, yes per hour. I was thinking primarily of the vane mechanics. Will have to do a sum to see what that means per year. A 1 in 10 million chance it will go wrong in any given hour still seems a stretch.
G-VHOT incident report suggests around 1 in 100k hours for AOA sensor (vane + resolver) failure rate, I'm sure I've seen similar numbers elsewhere as well. You then need the probability of failure being fail-high (there are other failure modes), which I have no information on, and the probability that fail-high on one sensor will trigger MCAS, which will be somewhere around 1/2 (maybe more - left side seems more susceptible (ramp damage?) and left side is also more likely active input as always selected after power-off reset). I agree that getting to 10^-7 seems a stretch, maybe I'm missing something though.