[QUOTE=Jhieminga;11323725]There is an important caveat in that everything that adds complexity also adds ways for things to go wrong. Such a calculated figure, when continuously used to validate the air-data derived figures, in itself is based on sensor input. What if that sensor fails? Another single point failure that you were trying to avoid. What if the calculation is somehow incorrect? As mentioned, training already covers partial panel situations where one or more parameters are not available or cannot be trusted. Any pilot should be able to provide the needed error-checking based on basic inputs such as power setting, attitude and environment, although the accident record does not show a perfect score.[/QUOTE
I take your point.The pilot may well be able to identify an error - provided he has noticed it, and there is no too distracting emergency going on. However, as to failure, there are two ways for this proposed system to fail. 1) It could indicate an error where none exists- in which case no harm is done except to worry the pilot unnecessarily: or 2) It could fail to register an actual error, in which case the pilot is no worse off than he would have been without the system.
For certain multiple failures, I concede that the system might be able only to indicate a Best Guess at the unreliable subset of instruments, but the warning could indicate the uncertainty.