Originally Posted by
Rude_mechanical
Nowadays, the readings of all the instruments are, or surely could be, made available as analogue or digital signals. It would be simple to apply these signals to a continuously-running mathematical model of the aircraft's behaviour, detect which of them is inconsistent with the state derived from the other instruments, and display the appropriate warning. Where instrument redundancy is provided (e.g. captain and co-pilot have independent ASI), this task becomes trivial. Input to the model from the functioning ASI would provide an internally self-consistent state: Input from the faulty one would not. I suggest that most single-point failures could be identified in this way, and even multiple failures (such as might result from damage or ice) could be detectable, if not identifiable.
I have no doubt that this concept could be implemented. However, the cost of development and certification of inovative designs can be huge. Airframers will continue to use tried and tested methods that already have approval until the certification requirements change.
You have already seen from replies to your post that pilots believe they have the training and experience to ignore misleading data and only use the valid data. The accident record would suggest that some flight crew were not as good at this as they may have thought they were.
Bottom line is that operators are reluctant to pay for any system enhancements that don't have a relatively short term economic advantage. Systems that increase safety but which are not required for certification don't sell well.