Is an all electric instrument powered SR22 really preferable to an airplane with different modes of power for flight critical instruments such as the SR20? 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!
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!
Is an all electric instrument powered SR22 really preferable to an airplane with different modes of power for flight critical instruments such as the SR20? 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!
Well, in my 10 years of flying power I have only had one in flight failure - the vaccum pump!
I can assure you that you will not find any vaccum driven intruments in the cockpit of a new 777 or 340!
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!
I was taught that the response to an electric fire was to turn off the master switch and fly the plane since the engine would keep running and all the important instruments would continue to function.
Interesting question. Maybe they will have the electrical system set up so you can shut off everything except one battery operating the attitude indicator. There has to be someway to respond to an electrical fire without losing all means of flying the plane in IFR.
I was taught that the response to an electric fire was to turn off the master switch and fly the plane since the engine would keep running and all the important instruments would continue to function.
Interesting question. Maybe they will have the electrical system set up so you can shut off everything except one battery operating the attitude indicator. There has to be someway to respond to an electrical fire without losing all means of flying the plane in IFR.
I was taught that the response to an electric fire was to turn off the master switch and fly the plane since the engine would keep running and all the important instruments would continue to function.
The problem with a vacuum failure is that its not always easy to spot. You really have to be alert. And if you’re late in picking it up, it could be too late. (Check the NTSB report of the R.I. crash of the P32 earlier this month.)
In the extremely unlikely event that all electric fails, the compass should keep your wings level until you have time to set up your portable GPS.