Originally Posted by Safety Concerns
Maybe I am missing the point here but the AOA's didn't fail.
The AoA sensors most definitely did fail. They did not provide correct information about the AoA; those that froze provided incorrect information.
The usual definitions of "failure" have something about not fulfilling the intended function.
Now, you may like to argue, given what you said, that they were not faulty. I would argue they were not faulty, for example. The reason they were not faulty is that a known requirement for correct operation was violated; they were used outside of the intended and prescribed environmental parameters. I use the word "fault" to mean the cause(s) of a failure while operating inside the requirements.
Originally Posted by Safety Concerns
You cannot pre-empt that scenario. You cannot detect that event you can only at best warn of discrepencies between the 3 signal sources.
I think you can detect it, under certain assumptions. Assuming that other sensors (pitots and static ports) are working correctly, you can detect it precisely the way that Airbus says that crew can detect it from the instrument readings. The question is whether you would want to go that route with the systems; assuming that the pitot-static systems are working correctly is not universally valid, as we have learnt from the Birgenair and Aeroperu accidents, the A320 rainstorm-contamination incidents, and the ice-particle-icing incidents with A330/A340 series aircraft.
PBL