I think things look pretty dire for anyone at night time IFR when all battery power has gone. Someone holding the torch up to illuminate what standby instrumentation is left - no airtifical horizon, no comms - no body to talk to, no nav aids - just a compass.
Think I would be asking the cabin crew to get a pax to see if they had a portable GPS on them.
I understand the APU of a 744 is not designed to run inflight.
Anyone know what happens to the windows when they lose electrical power/heating for an extended period of time (i dont know - just a question here)