Redundancy is a well-accepted (at least in aeronautics) way of providing robustness. When designing onboard systems for aircraft, it is not unusual to have a function with a higher level of design assurance which is implemented by a set of similar devices with a lesser level using a majority vote.

See multi-version dissimilar software: https://en.wikipedia.org/wiki/N-version_programming

Furthermore most modern planes are designed to be able to fly with one engine inoperative, even those which have only two engines.