No idea about Boeing, but yes for Airbus. Every “computer&quot; is actually two computers, one is the active computer (COM, command) and one is the inactive computer (MON, monitoring). Both still perform the same calculations based on the same input, however they use different software and hardware. There is a watchdog inbetween the two that verifies the results against each other, just in case there is a bug in the hardware or software. Then, you also have multiples of these computers, eg. there are two ELACs and three SECs. The ELACs and SECs are fed data from a different air data inertial reference unit (ADIRU) and use a different hydraulic line to actuate the flight controls. And lastly the results the ELACs and SECs come up with also have to agree with each other or the result is thrown out.<p>All of that redundency makes it possible to build some really robust flight envelope systems that keep the airplane within safe margins.<p>* I should note that all of this applies to the A320 family, the systems have been developed even further in recent years. For example with the A350 Airbus made some steps towards allowing the flight computers to be used in Simulators so that the same software&#x2F;hardware as on the real plane can be used.