title_body: What is the point of a dual-gyro setup for a FC? When looking for a flight controller for a drone build, I have seen some FCs with dual-gyros. What is the purpose of having two gyros on a FC? (Are there any advantages or disadvantages)
upvoted_answer: A major advantage is redundancy, so that the aircraft can continue flying if one fails. It is also common to see multiple GNSS (e.g. GPS) receivers, and sometimes even a redundant flight controller.
  
  Of course, the problem with only two is that the software can't necessarily tell which of them has failed; 'at least three' is common for high resilience applications as it is much less likely for two failures at the same time (barring external factors, such as a power spike.)
  Going further, you can also use different brands and/or technologies to remove the risk of a design or manufacturing flaw causing them all to fail at the same time.
  
  The typical disadvantages apply - increased cost, weight and power consumption - but also software complexity increases as you need to have a method for handling the potentially erroneous data.