"On a recent A320 sim-check, we had the following scenario : In T/O just after rotation, we got 2 unreliable ADR`s, that both had the same failure of increasing airspeed, rapidly increasing to above 400 kts. That means, that even though they are faulty, they wote out the remaining good ADR."
Not a pilot, but in another life I wrote medical/control software.
You MUST build in extensive sanity checks for rational behaviour and rational trends.
When in level flight/engines running normally, if the logic is suddenly informed of the sort of deceleration/speed loss more often associated with cumulo-granite encounters, it would be wise for the logic to be sceptical about the information before passing it on all loud and flashing to the flight-deck.
Eg:- Blood pressure readings from 3 independent sources
S1 shows a blood pressure and trend within the expected range
S2 shows an instantaneous BP increase to insane levels
S3 shows an instantaneous BP increase to insane levels
For S2 and S3 (irrational) to be able to outvote and drop S1 (rational) from the BP display is neither reasonable nor sensible.
As another example it is probably sensible to reject patient ages over 220 years, burns of 150% or 50kg newborn babies....
Much better to say sweetly;"Hi guys! I've just lost all my indicators and the AP has dropped out. 2 seconds ago I knew you were at M0.82, wings level, trimmed at 3deg NU and all was well, so don't do anthing hasty."
Mac