To add to this, usually most of the systems in avionics or support systems on the ground are dual-hardware (when not more). There's lots of work done to ensure

To add to this, usually most of the systems in avionics or support systems on the ground are dual-hardware (when not more). There's lots of work done to ensure there's no single point of failure and hardware (and more and more, software) failures are handled safely. Regulators add every 5-10y some pressure on time-to-recovery and acceptable data of service loss (counted in milliseconds even on ground systems). Erlang didn't invent much there, and restarting/rebooting isn't always possible (try doing that in less than 10ms). Sometimes, the application itself needs to handle problems. This puts lots of 'classic IT' (interface bonding, fail overs, etc.) stuff to the bin very quick.