Thanks to all who have responded so far. To narrow the question a little more, what if all charts were in digital format running on some sort of display device (laptop or Avionics).
How important would it be for this system to be 'full-up' available? Of course there are many different primary and secondary failure scenarios that could affect viewing charts on a 'powered device', along with the probabilities of each occurring and alternative means to acquire information(cascade failures, communications, 'benign-ness' of the region, and so on)...
The question now is how significant, or important, would the charts be in an ETOPs configuration if they were digital and the unit subscribed to ship's power - a system that has probabilities of failure?
Please forgive me of any message posting irregularities; I am a new user of this site.
Thanks again.