Sometimes completely different forms of powering critical instruments can be safer than
dual forms of the same kind of system! Just interested in other opinions on this subject!
I agree that it’s an interesting question. As I understand it, the logic of the new system is to make up in depth of redundancy what it gives up in variety. That is, again as I understand it:
default power is #1 Alternator;
if that fails, you turn to #2 Alternator;
if both of them fail, you go to the battery;
if that fails or gets used up, you go to the second battery.
(Is this what others understand too?)
Now, in real-life situations, if Alt1 failed, you’d start looking more carefully at Alt2 and the overall electric situation. And if Alt2 failed too, I at least would be looking for the nearest airport in a big hurry. The question is whether this four-level system would be better for getting you through a difficult situation – turbulent IMC, at a distance from any airport – than the traditional vacuum system.
So the question is: what is the fault that might simultaneously disable all four of these power systems, leaving you worse off than you would be if you had a more varied system, eg with a conventional vacuum pump. All I can think of is some catastrophic wiring failure, perhaps from a fire. And that would presumably leave you screwed in any situation…
Except for the parachute!