DozyWannabe
They were, and there was a service bulletin in effect to replace the components (along with pilot information to assist recovery from the issue) - unfortunately the airframe that became AF447 had not been taken into MX for that fix yet.
"Redundancy is "powerful" when critical elements do not fail simultaneously. And UAS cases show clearly simultaneous "failing" (due product limitation) Simultaneous "failure" of critical elements should be reported immediately.
To the crew, and in Real Time.
Well, the worst-case scenario where the automatics can continue to function is, yes, because a software-driven triple-redundant quorum can only be effective if two components are working correctly (in this case giving readings within the acceptable tolerance range)
Compare the previous generation's B757 - classic triple redundancy with the flight computers linked to a single air data input at any one time - where, originally, the first warning you got was "MACH TRIM - RUDDER RATIO". This is logical in terms of the systems engineering, but to a pilot the message could be confusing. They later added an "AIRSPEED DISAGREE" warning if I recall correctly.
Now, after clarifying to you i would like to repeat the Question (yet posted earlier): Why they put this redundancy? For what reason? What benefit?
When reviewing earlier posts i found this and i am now clarifying to you what i said.