[jacquesm]

You have just complicated the system considerably. If you want something to work during an emergency you're going to have to keep it as simple as possible. Also, some emergencies happen so fast that if the system has to switch on 'when an emergency has triggered' then you're too late.

Define: 'going off the flight path'...

In theory this is a simple problem to solve, just install a couple of webcams and hook them up to the in-flight wi-fi. In some cases that might even work. But if you want it to work in all the cases, especially those cases where things are going wrong then you'll need to think this through very carefully or it will be worse than useless.