Reply to post: Re: Hey software, get the fuck out of the way!

Boeing 737 pilots battled confused safety system that plunged aircraft to their deaths – black box

eldakka Silver badge

Re: Hey software, get the fuck out of the way!

Look at the two lines for the Angle of Attack (AoA) sensors. One is for the left and one is for the right. Notice that the lines are separated? At any given time, the AoA sensors should never be separate. They're meant to be redundant so the readings are meant to be the same.

You can't really have an effective redundant system with only 2 lines, you need 3. If one sensor fails with 2 lines, then which one is the faulty one? You can't reliably identify a single-sensor failure if you only have 2 sensors. With 3, you can detect a single-sensor failure. Of course, 2 sensor failures are then possible, but the chances of that are orders of magnitude less than single-sensor failures, and the sort of thing that'd make 2 (or more), widely-dispersed sensors fail is likely to be fatal to the aircraft anyway.

Any critical sensor systems should be triply redundant, not dual, at least in larger (bigger than dash-8's) passenger aircraft. After all, we are talking about more than a hundred lives (more than 500 in the largest aircraft models) per aircraft in these cases.

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