When you have 3, 5, 7, (odd number), etc. critical elements, your System is able to:
1. Compare elements trying to figure out the “truth” i.e. their correct “output”
2. “Vote” to select the best ones (the ones that are probably presenting correct results)
3. Implement a more “fault tolerant” system for a better (safer) System availability
4. Promote a “graceful degradation” in the overall system
Remarkable,
Engines have only 2 channels for control, 2 sensors for each parameter; B777 has only 2 AOA vanes fitted.
What happened with redundancy here? even more 'ridiculous' design or clever engineering?