Re:United orders 50 new Airbus long-range jets to replace Bo...
by Xixi on Wednesday December 04, 2019 @03:27PM
(#21706549)
The Qantas Flight 72 incident was quite a bit different, as all AoA sensors were working correctly. The issue was due to corruption on one of the CPU exploiting these AoA sensors value [1]. Though you are entirely correct that there was a design flaw and the incident should not have happened, since these corrupted values ended up overriding the correctly calculated ones from the other ADIRU units.
[1] "The exact nature of the corruption was that the ADIRU CPU erroneously re-labelled the altitude data word so that the binary data that represented 37,012 (the altitude at the time of the incident) would represent an angle of attack of 50.625 degrees." https://en.wikipedia.org/wiki/Qantas_Flight_72#Potential_tri...
I'm not sure this is true in a practical sense. For example, Airbus does the same unbelievable things with AoA sensors that Boeing did with MCAS: even if they have two or three of them on an aircraft, they don't compare them before allowing one sensor to drive automatic functions, so a single failed sensor can cause the airplane to do unexpected and dangerous things (for example, multiple uncommanded pitch down events on Quantas Flight 72). A true adversarial regulator would never have allowed such design flaws.