In response to a popular news story about a security researcher claiming he could crash a plane remotely via smartphone, MeFi member backseatpilot explains why concerns over this may be overblown:
The airplane is designed to remain safe and functional even if the FMSs fail. Again, multiply redundant systems. Multiple MFDs can fail, multiple autopilots can fail, you could have a total electrical failure and still fly the airplane. Even the Dreamliner, the most electric airplane in the world, is designed to fly with a total electrical failure.